Merge branch 'gve-dqo'

Bailey Forrest says:

====================
gve: Introduce DQO descriptor format

DQO is the descriptor format for our next generation virtual NIC. The existing
descriptor format will be referred to as "GQI" in the patch set.

One major change with DQO is it uses dual descriptor rings for both TX and RX
queues.

The TX path uses a TX queue to send descriptors to HW, and receives packet
completion events on a TX completion queue.

The RX path posts buffers to HW using an RX buffer queue and receives incoming
packets on an RX queue.

One important note is that DQO descriptors and doorbells are little endian. We
continue to use the existing big endian control plane infrastructure.

The general format of the patch series is:
- Refactor existing code/data structures to be shared by DQO
- Expand admin queues to support DQO device setup
- Expand data structures and device setup to support DQO
- Add logic to setup DQO queues
- Implement datapath
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/device_drivers/ethernet/google/gve.rst

@@ -47,13 +47,24 @@ The driver interacts with the device in the following ways:
  - Transmit and Receive Queues
     - See description below
 
+Descriptor Formats
+------------------
+GVE supports two descriptor formats: GQI and DQO. These two formats have
+entirely different descriptors, which will be described below.
+
 Registers
 ---------
-All registers are MMIO and big endian.
+All registers are MMIO.
 
 The registers are used for initializing and configuring the device as well as
 querying device status in response to management interrupts.
 
+Endianness
+----------
+- Admin Queue messages and registers are all Big Endian.
+- GQI descriptors and datapath registers are Big Endian.
+- DQO descriptors and datapath registers are Little Endian.
+
 Admin Queue (AQ)
 ----------------
 The Admin Queue is a PAGE_SIZE memory block, treated as an array of AQ
@@ -97,10 +108,10 @@ the queues associated with that interrupt.
 The handler for these irqs schedule the napi for that block to run
 and poll the queues.
 
-Traffic Queues
---------------
-gVNIC's queues are composed of a descriptor ring and a buffer and are
-assigned to a notification block.
+GQI Traffic Queues
+------------------
+GQI queues are composed of a descriptor ring and a buffer and are assigned to a
+notification block.
 
 The descriptor rings are power-of-two-sized ring buffers consisting of
 fixed-size descriptors. They advance their head pointer using a __be32
@@ -121,3 +132,35 @@ Receive
 The buffers for receive rings are put into a data ring that is the same
 length as the descriptor ring and the head and tail pointers advance over
 the rings together.
+
+DQO Traffic Queues
+------------------
+- Every TX and RX queue is assigned a notification block.
+
+- TX and RX buffers queues, which send descriptors to the device, use MMIO
+  doorbells to notify the device of new descriptors.
+
+- RX and TX completion queues, which receive descriptors from the device, use a
+  "generation bit" to know when a descriptor was populated by the device. The
+  driver initializes all bits with the "current generation". The device will
+  populate received descriptors with the "next generation" which is inverted
+  from the current generation. When the ring wraps, the current/next generation
+  are swapped.
+
+- It's the driver's responsibility to ensure that the RX and TX completion
+  queues are not overrun. This can be accomplished by limiting the number of
+  descriptors posted to HW.
+
+- TX packets have a 16 bit completion_tag and RX buffers have a 16 bit
+  buffer_id. These will be returned on the TX completion and RX queues
+  respectively to let the driver know which packet/buffer was completed.
+
+Transmit
+~~~~~~~~
+A packet's buffers are DMA mapped for the device to access before transmission.
+After the packet was successfully transmitted, the buffers are unmapped.
+
+Receive
+~~~~~~~
+The driver posts fixed sized buffers to HW on the RX buffer queue. The packet
+received on the associated RX queue may span multiple descriptors.

drivers/net/ethernet/google/Kconfig

@@ -17,7 +17,7 @@ if NET_VENDOR_GOOGLE
 
 config GVE
 	tristate "Google Virtual NIC (gVNIC) support"
-	depends on PCI_MSI
+	depends on (PCI_MSI && (X86 || CPU_LITTLE_ENDIAN))
 	help
 	  This driver supports Google Virtual NIC (gVNIC)"
 

drivers/net/ethernet/google/gve/Makefile

 # Makefile for the Google virtual Ethernet (gve) driver
 
 obj-$(CONFIG_GVE) += gve.o
-gve-objs := gve_main.o gve_tx.o gve_rx.o gve_ethtool.o gve_adminq.o
+gve-objs := gve_main.o gve_tx.o gve_tx_dqo.o gve_rx.o gve_rx_dqo.o gve_ethtool.o gve_adminq.o gve_utils.o

drivers/net/ethernet/google/gve/gve.h

 /* SPDX-License-Identifier: (GPL-2.0 OR MIT)
  * Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #ifndef _GVE_H_
@@ -11,7 +11,9 @@
 #include <linux/netdevice.h>
 #include <linux/pci.h>
 #include <linux/u64_stats_sync.h>
+
 #include "gve_desc.h"
+#include "gve_desc_dqo.h"
 
 #ifndef PCI_VENDOR_ID_GOOGLE
 #define PCI_VENDOR_ID_GOOGLE	0x1ae0
@@ -40,6 +42,11 @@
 
 #define GVE_DATA_SLOT_ADDR_PAGE_MASK (~(PAGE_SIZE - 1))
 
+/* PTYPEs are always 10 bits. */
+#define GVE_NUM_PTYPES	1024
+
+#define GVE_RX_BUFFER_SIZE_DQO 2048
+
 /* Each slot in the desc ring has a 1:1 mapping to a slot in the data ring */
 struct gve_rx_desc_queue {
 	struct gve_rx_desc *desc_ring; /* the descriptor ring */
@@ -51,7 +58,8 @@ struct gve_rx_desc_queue {
 struct gve_rx_slot_page_info {
 	struct page *page;
 	void *page_address;
-	u8 page_offset; /* flipped to second half? */
+	u32 page_offset; /* offset to write to in page */
+	int pagecnt_bias; /* expected pagecnt if only the driver has a ref */
 	u8 can_flip;
 };
 
@@ -76,17 +84,117 @@ struct gve_rx_data_queue {
 
 struct gve_priv;
 
-/* An RX ring that contains a power-of-two sized desc and data ring. */
+/* RX buffer queue for posting buffers to HW.
+ * Each RX (completion) queue has a corresponding buffer queue.
+ */
+struct gve_rx_buf_queue_dqo {
+	struct gve_rx_desc_dqo *desc_ring;
+	dma_addr_t bus;
+	u32 head; /* Pointer to start cleaning buffers at. */
+	u32 tail; /* Last posted buffer index + 1 */
+	u32 mask; /* Mask for indices to the size of the ring */
+};
+
+/* RX completion queue to receive packets from HW. */
+struct gve_rx_compl_queue_dqo {
+	struct gve_rx_compl_desc_dqo *desc_ring;
+	dma_addr_t bus;
+
+	/* Number of slots which did not have a buffer posted yet. We should not
+	 * post more buffers than the queue size to avoid HW overrunning the
+	 * queue.
+	 */
+	int num_free_slots;
+
+	/* HW uses a "generation bit" to notify SW of new descriptors. When a
+	 * descriptor's generation bit is different from the current generation,
+	 * that descriptor is ready to be consumed by SW.
+	 */
+	u8 cur_gen_bit;
+
+	/* Pointer into desc_ring where the next completion descriptor will be
+	 * received.
+	 */
+	u32 head;
+	u32 mask; /* Mask for indices to the size of the ring */
+};
+
+/* Stores state for tracking buffers posted to HW */
+struct gve_rx_buf_state_dqo {
+	/* The page posted to HW. */
+	struct gve_rx_slot_page_info page_info;
+
+	/* The DMA address corresponding to `page_info`. */
+	dma_addr_t addr;
+
+	/* Last offset into the page when it only had a single reference, at
+	 * which point every other offset is free to be reused.
+	 */
+	u32 last_single_ref_offset;
+
+	/* Linked list index to next element in the list, or -1 if none */
+	s16 next;
+};
+
+/* `head` and `tail` are indices into an array, or -1 if empty. */
+struct gve_index_list {
+	s16 head;
+	s16 tail;
+};
+
+/* Contains datapath state used to represent an RX queue. */
 struct gve_rx_ring {
 	struct gve_priv *gve;
+	union {
+		/* GQI fields */
+		struct {
 			struct gve_rx_desc_queue desc;
 			struct gve_rx_data_queue data;
+
+			/* threshold for posting new buffs and descs */
+			u32 db_threshold;
+		};
+
+		/* DQO fields. */
+		struct {
+			struct gve_rx_buf_queue_dqo bufq;
+			struct gve_rx_compl_queue_dqo complq;
+
+			struct gve_rx_buf_state_dqo *buf_states;
+			u16 num_buf_states;
+
+			/* Linked list of gve_rx_buf_state_dqo. Index into
+			 * buf_states, or -1 if empty.
+			 */
+			s16 free_buf_states;
+
+			/* Linked list of gve_rx_buf_state_dqo. Indexes into
+			 * buf_states, or -1 if empty.
+			 *
+			 * This list contains buf_states which are pointing to
+			 * valid buffers.
+			 *
+			 * We use a FIFO here in order to increase the
+			 * probability that buffers can be reused by increasing
+			 * the time between usages.
+			 */
+			struct gve_index_list recycled_buf_states;
+
+			/* Linked list of gve_rx_buf_state_dqo. Indexes into
+			 * buf_states, or -1 if empty.
+			 *
+			 * This list contains buf_states which have buffers
+			 * which cannot be reused yet.
+			 */
+			struct gve_index_list used_buf_states;
+		} dqo;
+	};
+
 	u64 rbytes; /* free-running bytes received */
 	u64 rpackets; /* free-running packets received */
 	u32 cnt; /* free-running total number of completed packets */
 	u32 fill_cnt; /* free-running total number of descs and buffs posted */
 	u32 mask; /* masks the cnt and fill_cnt to the size of the ring */
-	u32 db_threshold; /* threshold for posting new buffs and descs */
 	u64 rx_copybreak_pkt; /* free-running count of copybreak packets */
 	u64 rx_copied_pkt; /* free-running total number of copied packets */
 	u64 rx_skb_alloc_fail; /* free-running count of skb alloc fails */
@@ -97,6 +205,10 @@ struct gve_rx_ring {
 	struct gve_queue_resources *q_resources; /* head and tail pointer idx */
 	dma_addr_t q_resources_bus; /* dma address for the queue resources */
 	struct u64_stats_sync statss; /* sync stats for 32bit archs */
+
+	/* head and tail of skb chain for the current packet or NULL if none */
+	struct sk_buff *skb_head;
+	struct sk_buff *skb_tail;
 };
 
 /* A TX desc ring entry */
@@ -137,23 +249,161 @@ struct gve_tx_fifo {
 	struct gve_queue_page_list *qpl; /* QPL mapped into this FIFO */
 };
 
-/* A TX ring that contains a power-of-two sized desc ring and a FIFO buffer */
+/* TX descriptor for DQO format */
+union gve_tx_desc_dqo {
+	struct gve_tx_pkt_desc_dqo pkt;
+	struct gve_tx_tso_context_desc_dqo tso_ctx;
+	struct gve_tx_general_context_desc_dqo general_ctx;
+};
+
+enum gve_packet_state {
+	/* Packet is in free list, available to be allocated.
+	 * This should always be zero since state is not explicitly initialized.
+	 */
+	GVE_PACKET_STATE_UNALLOCATED,
+	/* Packet is expecting a regular data completion or miss completion */
+	GVE_PACKET_STATE_PENDING_DATA_COMPL,
+	/* Packet has received a miss completion and is expecting a
+	 * re-injection completion.
+	 */
+	GVE_PACKET_STATE_PENDING_REINJECT_COMPL,
+	/* No valid completion received within the specified timeout. */
+	GVE_PACKET_STATE_TIMED_OUT_COMPL,
+};
+
+struct gve_tx_pending_packet_dqo {
+	struct sk_buff *skb; /* skb for this packet */
+
+	/* 0th element corresponds to the linear portion of `skb`, should be
+	 * unmapped with `dma_unmap_single`.
+	 *
+	 * All others correspond to `skb`'s frags and should be unmapped with
+	 * `dma_unmap_page`.
+	 */
+	struct gve_tx_dma_buf bufs[MAX_SKB_FRAGS + 1];
+	u16 num_bufs;
+
+	/* Linked list index to next element in the list, or -1 if none */
+	s16 next;
+
+	/* Linked list index to prev element in the list, or -1 if none.
+	 * Used for tracking either outstanding miss completions or prematurely
+	 * freed packets.
+	 */
+	s16 prev;
+
+	/* Identifies the current state of the packet as defined in
+	 * `enum gve_packet_state`.
+	 */
+	u8 state;
+
+	/* If packet is an outstanding miss completion, then the packet is
+	 * freed if the corresponding re-injection completion is not received
+	 * before kernel jiffies exceeds timeout_jiffies.
+	 */
+	unsigned long timeout_jiffies;
+};
+
+/* Contains datapath state used to represent a TX queue. */
 struct gve_tx_ring {
 	/* Cacheline 0 -- Accessed & dirtied during transmit */
+	union {
+		/* GQI fields */
+		struct {
 			struct gve_tx_fifo tx_fifo;
 			u32 req; /* driver tracked head pointer */
 			u32 done; /* driver tracked tail pointer */
+		};
+
+		/* DQO fields. */
+		struct {
+			/* Linked list of gve_tx_pending_packet_dqo. Index into
+			 * pending_packets, or -1 if empty.
+			 *
+			 * This is a consumer list owned by the TX path. When it
+			 * runs out, the producer list is stolen from the
+			 * completion handling path
+			 * (dqo_compl.free_pending_packets).
+			 */
+			s16 free_pending_packets;
+
+			/* Cached value of `dqo_compl.hw_tx_head` */
+			u32 head;
+			u32 tail; /* Last posted buffer index + 1 */
+
+			/* Index of the last descriptor with "report event" bit
+			 * set.
+			 */
+			u32 last_re_idx;
+		} dqo_tx;
+	};
 
 	/* Cacheline 1 -- Accessed & dirtied during gve_clean_tx_done */
-	__be32 last_nic_done ____cacheline_aligned; /* NIC tail pointer */
+	union {
+		/* GQI fields */
+		struct {
+			/* NIC tail pointer */
+			__be32 last_nic_done;
+		};
+
+		/* DQO fields. */
+		struct {
+			u32 head; /* Last read on compl_desc */
+
+			/* Tracks the current gen bit of compl_q */
+			u8 cur_gen_bit;
+
+			/* Linked list of gve_tx_pending_packet_dqo. Index into
+			 * pending_packets, or -1 if empty.
+			 *
+			 * This is the producer list, owned by the completion
+			 * handling path. When the consumer list
+			 * (dqo_tx.free_pending_packets) is runs out, this list
+			 * will be stolen.
+			 */
+			atomic_t free_pending_packets;
+
+			/* Last TX ring index fetched by HW */
+			atomic_t hw_tx_head;
+
+			/* List to track pending packets which received a miss
+			 * completion but not a corresponding reinjection.
+			 */
+			struct gve_index_list miss_completions;
+
+			/* List to track pending packets that were completed
+			 * before receiving a valid completion because they
+			 * reached a specified timeout.
+			 */
+			struct gve_index_list timed_out_completions;
+		} dqo_compl;
+	} ____cacheline_aligned;
 	u64 pkt_done; /* free-running - total packets completed */
 	u64 bytes_done; /* free-running - total bytes completed */
 	u64 dropped_pkt; /* free-running - total packets dropped */
 	u64 dma_mapping_error; /* count of dma mapping errors */
 
 	/* Cacheline 2 -- Read-mostly fields */
-	union gve_tx_desc *desc ____cacheline_aligned;
-	struct gve_tx_buffer_state *info; /* Maps 1:1 to a desc */
+	union {
+		/* GQI fields */
+		struct {
+			union gve_tx_desc *desc;
+
+			/* Maps 1:1 to a desc */
+			struct gve_tx_buffer_state *info;
+		};
+
+		/* DQO fields. */
+		struct {
+			union gve_tx_desc_dqo *tx_ring;
+			struct gve_tx_compl_desc *compl_ring;
+
+			struct gve_tx_pending_packet_dqo *pending_packets;
+			s16 num_pending_packets;
+
+			u32 complq_mask; /* complq size is complq_mask + 1 */
+		} dqo;
+	} ____cacheline_aligned;
 	struct netdev_queue *netdev_txq;
 	struct gve_queue_resources *q_resources; /* head and tail pointer idx */
 	struct device *dev;
@@ -167,6 +417,7 @@ struct gve_tx_ring {
 	u32 ntfy_id; /* notification block index */
 	dma_addr_t bus; /* dma address of the descr ring */
 	dma_addr_t q_resources_bus; /* dma address of the queue resources */
+	dma_addr_t complq_bus_dqo; /* dma address of the dqo.compl_ring */
 	struct u64_stats_sync statss; /* sync stats for 32bit archs */
 } ____cacheline_aligned;
 
@@ -194,6 +445,31 @@ struct gve_qpl_config {
 	unsigned long *qpl_id_map; /* bitmap of used qpl ids */
 };
 
+struct gve_options_dqo_rda {
+	u16 tx_comp_ring_entries; /* number of tx_comp descriptors */
+	u16 rx_buff_ring_entries; /* number of rx_buff descriptors */
+};
+
+struct gve_ptype {
+	u8 l3_type;  /* `gve_l3_type` in gve_adminq.h */
+	u8 l4_type;  /* `gve_l4_type` in gve_adminq.h */
+};
+
+struct gve_ptype_lut {
+	struct gve_ptype ptypes[GVE_NUM_PTYPES];
+};
+
+/* GVE_QUEUE_FORMAT_UNSPECIFIED must be zero since 0 is the default value
+ * when the entire configure_device_resources command is zeroed out and the
+ * queue_format is not specified.
+ */
+enum gve_queue_format {
+	GVE_QUEUE_FORMAT_UNSPECIFIED	= 0x0,
+	GVE_GQI_RDA_FORMAT		= 0x1,
+	GVE_GQI_QPL_FORMAT		= 0x2,
+	GVE_DQO_RDA_FORMAT		= 0x3,
+};
+
 struct gve_priv {
 	struct net_device *dev;
 	struct gve_tx_ring *tx; /* array of tx_cfg.num_queues */
@@ -216,7 +492,6 @@ struct gve_priv {
 	u64 num_registered_pages; /* num pages registered with NIC */
 	u32 rx_copybreak; /* copy packets smaller than this */
 	u16 default_num_queues; /* default num queues to set up */
-	u8 raw_addressing; /* 1 if this dev supports raw addressing, 0 otherwise */
 
 	struct gve_queue_config tx_cfg;
 	struct gve_queue_config rx_cfg;
@@ -251,6 +526,7 @@ struct gve_priv {
 	u32 adminq_set_driver_parameter_cnt;
 	u32 adminq_report_stats_cnt;
 	u32 adminq_report_link_speed_cnt;
+	u32 adminq_get_ptype_map_cnt;
 
 	/* Global stats */
 	u32 interface_up_cnt; /* count of times interface turned up since last reset */
@@ -275,6 +551,14 @@ struct gve_priv {
 
 	/* Gvnic device link speed from hypervisor. */
 	u64 link_speed;
+
+	struct gve_options_dqo_rda options_dqo_rda;
+	struct gve_ptype_lut *ptype_lut_dqo;
+
+	/* Must be a power of two. */
+	int data_buffer_size_dqo;
+
+	enum gve_queue_format queue_format;
 };
 
 enum gve_service_task_flags_bit {
@@ -454,14 +738,20 @@ static inline u32 gve_rx_idx_to_ntfy(struct gve_priv *priv, u32 queue_idx)
  */
 static inline u32 gve_num_tx_qpls(struct gve_priv *priv)
 {
-	return priv->raw_addressing ? 0 : priv->tx_cfg.num_queues;
+	if (priv->queue_format != GVE_GQI_QPL_FORMAT)
+		return 0;
+
+	return priv->tx_cfg.num_queues;
 }
 
 /* Returns the number of rx queue page lists
  */
 static inline u32 gve_num_rx_qpls(struct gve_priv *priv)
 {
-	return priv->raw_addressing ? 0 : priv->rx_cfg.num_queues;
+	if (priv->queue_format != GVE_GQI_QPL_FORMAT)
+		return 0;
+
+	return priv->rx_cfg.num_queues;
 }
 
 /* Returns a pointer to the next available tx qpl in the list of qpls
@@ -515,6 +805,12 @@ static inline enum dma_data_direction gve_qpl_dma_dir(struct gve_priv *priv,
 		return DMA_FROM_DEVICE;
 }
 
+static inline bool gve_is_gqi(struct gve_priv *priv)
+{
+	return priv->queue_format == GVE_GQI_RDA_FORMAT ||
+		priv->queue_format == GVE_GQI_QPL_FORMAT;
+}
+
 /* buffers */
 int gve_alloc_page(struct gve_priv *priv, struct device *dev,
 		   struct page **page, dma_addr_t *dma,
@@ -525,14 +821,14 @@ void gve_free_page(struct device *dev, struct page *page, dma_addr_t dma,
 netdev_tx_t gve_tx(struct sk_buff *skb, struct net_device *dev);
 bool gve_tx_poll(struct gve_notify_block *block, int budget);
 int gve_tx_alloc_rings(struct gve_priv *priv);
-void gve_tx_free_rings(struct gve_priv *priv);
+void gve_tx_free_rings_gqi(struct gve_priv *priv);
 __be32 gve_tx_load_event_counter(struct gve_priv *priv,
 				 struct gve_tx_ring *tx);
 /* rx handling */
 void gve_rx_write_doorbell(struct gve_priv *priv, struct gve_rx_ring *rx);
 bool gve_rx_poll(struct gve_notify_block *block, int budget);
 int gve_rx_alloc_rings(struct gve_priv *priv);
-void gve_rx_free_rings(struct gve_priv *priv);
+void gve_rx_free_rings_gqi(struct gve_priv *priv);
 bool gve_clean_rx_done(struct gve_rx_ring *rx, int budget,
 		       netdev_features_t feat);
 /* Reset */

drivers/net/ethernet/google/gve/gve_adminq.c

 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
 /* Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #include <linux/etherdevice.h>
@@ -18,6 +18,8 @@
 "Expected: length=%d, feature_mask=%x.\n" \
 "Actual: length=%d, feature_mask=%x.\n"
 
+#define GVE_DEVICE_OPTION_TOO_BIG_FMT "Length of %s option larger than expected. Possible older version of guest driver.\n"
+
 static
 struct gve_device_option *gve_get_next_option(struct gve_device_descriptor *descriptor,
 					      struct gve_device_option *option)
@@ -33,28 +35,81 @@ struct gve_device_option *gve_get_next_option(struct gve_device_descriptor *desc
 static
 void gve_parse_device_option(struct gve_priv *priv,
 			     struct gve_device_descriptor *device_descriptor,
-			     struct gve_device_option *option)
+			     struct gve_device_option *option,
+			     struct gve_device_option_gqi_rda **dev_op_gqi_rda,
+			     struct gve_device_option_gqi_qpl **dev_op_gqi_qpl,
+			     struct gve_device_option_dqo_rda **dev_op_dqo_rda)
 {
+	u32 req_feat_mask = be32_to_cpu(option->required_features_mask);
 	u16 option_length = be16_to_cpu(option->option_length);
 	u16 option_id = be16_to_cpu(option->option_id);
 
-	switch (option_id) {
-	case GVE_DEV_OPT_ID_RAW_ADDRESSING:
-		/* If the length or feature mask doesn't match,
-		 * continue without enabling the feature.
+	/* If the length or feature mask doesn't match, continue without
+	 * enabling the feature.
 	 */
-		if (option_length != GVE_DEV_OPT_LEN_RAW_ADDRESSING ||
-		    option->feat_mask != cpu_to_be32(GVE_DEV_OPT_FEAT_MASK_RAW_ADDRESSING)) {
-			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT, "Raw Addressing",
-				 GVE_DEV_OPT_LEN_RAW_ADDRESSING,
-				 cpu_to_be32(GVE_DEV_OPT_FEAT_MASK_RAW_ADDRESSING),
-				 option_length, option->feat_mask);
-			priv->raw_addressing = 0;
-		} else {
+	switch (option_id) {
+	case GVE_DEV_OPT_ID_GQI_RAW_ADDRESSING:
+		if (option_length != GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING ||
+		    req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RAW_ADDRESSING) {
+			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+				 "Raw Addressing",
+				 GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING,
+				 GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RAW_ADDRESSING,
+				 option_length, req_feat_mask);
+			break;
+		}
+
 		dev_info(&priv->pdev->dev,
-				 "Raw addressing device option enabled.\n");
-			priv->raw_addressing = 1;
+			 "Gqi raw addressing device option enabled.\n");
+		priv->queue_format = GVE_GQI_RDA_FORMAT;
+		break;
+	case GVE_DEV_OPT_ID_GQI_RDA:
+		if (option_length < sizeof(**dev_op_gqi_rda) ||
+		    req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RDA) {
+			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+				 "GQI RDA", (int)sizeof(**dev_op_gqi_rda),
+				 GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RDA,
+				 option_length, req_feat_mask);
+			break;
+		}
+
+		if (option_length > sizeof(**dev_op_gqi_rda)) {
+			dev_warn(&priv->pdev->dev,
+				 GVE_DEVICE_OPTION_TOO_BIG_FMT, "GQI RDA");
+		}
+		*dev_op_gqi_rda = (void *)(option + 1);
+		break;
+	case GVE_DEV_OPT_ID_GQI_QPL:
+		if (option_length < sizeof(**dev_op_gqi_qpl) ||
+		    req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_GQI_QPL) {
+			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+				 "GQI QPL", (int)sizeof(**dev_op_gqi_qpl),
+				 GVE_DEV_OPT_REQ_FEAT_MASK_GQI_QPL,
+				 option_length, req_feat_mask);
+			break;
+		}
+
+		if (option_length > sizeof(**dev_op_gqi_qpl)) {
+			dev_warn(&priv->pdev->dev,
+				 GVE_DEVICE_OPTION_TOO_BIG_FMT, "GQI QPL");
 		}
+		*dev_op_gqi_qpl = (void *)(option + 1);
+		break;
+	case GVE_DEV_OPT_ID_DQO_RDA:
+		if (option_length < sizeof(**dev_op_dqo_rda) ||
+		    req_feat_mask != GVE_DEV_OPT_REQ_FEAT_MASK_DQO_RDA) {
+			dev_warn(&priv->pdev->dev, GVE_DEVICE_OPTION_ERROR_FMT,
+				 "DQO RDA", (int)sizeof(**dev_op_dqo_rda),
+				 GVE_DEV_OPT_REQ_FEAT_MASK_DQO_RDA,
+				 option_length, req_feat_mask);
+			break;
+		}
+
+		if (option_length > sizeof(**dev_op_dqo_rda)) {
+			dev_warn(&priv->pdev->dev,
+				 GVE_DEVICE_OPTION_TOO_BIG_FMT, "DQO RDA");
+		}
+		*dev_op_dqo_rda = (void *)(option + 1);
 		break;
 	default:
 		/* If we don't recognize the option just continue
@@ -65,6 +120,39 @@ void gve_parse_device_option(struct gve_priv *priv,
 	}
 }
 
+/* Process all device options for a given describe device call. */
+static int
+gve_process_device_options(struct gve_priv *priv,
+			   struct gve_device_descriptor *descriptor,
+			   struct gve_device_option_gqi_rda **dev_op_gqi_rda,
+			   struct gve_device_option_gqi_qpl **dev_op_gqi_qpl,
+			   struct gve_device_option_dqo_rda **dev_op_dqo_rda)
+{
+	const int num_options = be16_to_cpu(descriptor->num_device_options);
+	struct gve_device_option *dev_opt;
+	int i;
+
+	/* The options struct directly follows the device descriptor. */
+	dev_opt = (void *)(descriptor + 1);
+	for (i = 0; i < num_options; i++) {
+		struct gve_device_option *next_opt;
+
+		next_opt = gve_get_next_option(descriptor, dev_opt);
+		if (!next_opt) {
+			dev_err(&priv->dev->dev,
+				"options exceed device_descriptor's total length.\n");
+			return -EINVAL;
+		}
+
+		gve_parse_device_option(priv, descriptor, dev_opt,
+					dev_op_gqi_rda, dev_op_gqi_qpl,
+					dev_op_dqo_rda);
+		dev_opt = next_opt;
+	}
+
+	return 0;
+}
+
 int gve_adminq_alloc(struct device *dev, struct gve_priv *priv)
 {
 	priv->adminq = dma_alloc_coherent(dev, PAGE_SIZE,
@@ -88,6 +176,7 @@ int gve_adminq_alloc(struct device *dev, struct gve_priv *priv)
 	priv->adminq_set_driver_parameter_cnt = 0;
 	priv->adminq_report_stats_cnt = 0;
 	priv->adminq_report_link_speed_cnt = 0;
+	priv->adminq_get_ptype_map_cnt = 0;
 
 	/* Setup Admin queue with the device */
 	iowrite32be(priv->adminq_bus_addr / PAGE_SIZE,
@@ -293,6 +382,9 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv,
 	case GVE_ADMINQ_REPORT_LINK_SPEED:
 		priv->adminq_report_link_speed_cnt++;
 		break;
+	case GVE_ADMINQ_GET_PTYPE_MAP:
+		priv->adminq_get_ptype_map_cnt++;
+		break;
 	default:
 		dev_err(&priv->pdev->dev, "unknown AQ command opcode %d\n", opcode);
 	}
@@ -305,7 +397,8 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv,
  * The caller is also responsible for making sure there are no commands
  * waiting to be executed.
  */
-static int gve_adminq_execute_cmd(struct gve_priv *priv, union gve_adminq_command *cmd_orig)
+static int gve_adminq_execute_cmd(struct gve_priv *priv,
+				  union gve_adminq_command *cmd_orig)
 {
 	u32 tail, head;
 	int err;
@@ -350,6 +443,7 @@ int gve_adminq_configure_device_resources(struct gve_priv *priv,
 		.irq_db_stride = cpu_to_be32(sizeof(priv->ntfy_blocks[0])),
 		.ntfy_blk_msix_base_idx =
 					cpu_to_be32(GVE_NTFY_BLK_BASE_MSIX_IDX),
+		.queue_format = priv->queue_format,
 	};
 
 	return gve_adminq_execute_cmd(priv, &cmd);
@@ -369,27 +463,32 @@ static int gve_adminq_create_tx_queue(struct gve_priv *priv, u32 queue_index)
 {
 	struct gve_tx_ring *tx = &priv->tx[queue_index];
 	union gve_adminq_command cmd;
-	u32 qpl_id;
-	int err;
 
-	qpl_id = priv->raw_addressing ? GVE_RAW_ADDRESSING_QPL_ID : tx->tx_fifo.qpl->id;
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.opcode = cpu_to_be32(GVE_ADMINQ_CREATE_TX_QUEUE);
 	cmd.create_tx_queue = (struct gve_adminq_create_tx_queue) {
 		.queue_id = cpu_to_be32(queue_index),
-		.reserved = 0,
 		.queue_resources_addr =
 			cpu_to_be64(tx->q_resources_bus),
 		.tx_ring_addr = cpu_to_be64(tx->bus),
-		.queue_page_list_id = cpu_to_be32(qpl_id),
 		.ntfy_id = cpu_to_be32(tx->ntfy_id),
 	};
 
-	err = gve_adminq_issue_cmd(priv, &cmd);
-	if (err)
-		return err;
+	if (gve_is_gqi(priv)) {
+		u32 qpl_id = priv->queue_format == GVE_GQI_RDA_FORMAT ?
+			GVE_RAW_ADDRESSING_QPL_ID : tx->tx_fifo.qpl->id;
 
-	return 0;
+		cmd.create_tx_queue.queue_page_list_id = cpu_to_be32(qpl_id);
+	} else {
+		cmd.create_tx_queue.tx_ring_size =
+			cpu_to_be16(priv->tx_desc_cnt);
+		cmd.create_tx_queue.tx_comp_ring_addr =
+			cpu_to_be64(tx->complq_bus_dqo);
+		cmd.create_tx_queue.tx_comp_ring_size =
+			cpu_to_be16(priv->options_dqo_rda.tx_comp_ring_entries);
+	}
+
+	return gve_adminq_issue_cmd(priv, &cmd);
 }
 
 int gve_adminq_create_tx_queues(struct gve_priv *priv, u32 num_queues)
@@ -410,28 +509,41 @@ static int gve_adminq_create_rx_queue(struct gve_priv *priv, u32 queue_index)
 {
 	struct gve_rx_ring *rx = &priv->rx[queue_index];
 	union gve_adminq_command cmd;
-	u32 qpl_id;
-	int err;
 
-	qpl_id = priv->raw_addressing ? GVE_RAW_ADDRESSING_QPL_ID : rx->data.qpl->id;
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.opcode = cpu_to_be32(GVE_ADMINQ_CREATE_RX_QUEUE);
 	cmd.create_rx_queue = (struct gve_adminq_create_rx_queue) {
 		.queue_id = cpu_to_be32(queue_index),
-		.index = cpu_to_be32(queue_index),
-		.reserved = 0,
 		.ntfy_id = cpu_to_be32(rx->ntfy_id),
 		.queue_resources_addr = cpu_to_be64(rx->q_resources_bus),
-		.rx_desc_ring_addr = cpu_to_be64(rx->desc.bus),
-		.rx_data_ring_addr = cpu_to_be64(rx->data.data_bus),
-		.queue_page_list_id = cpu_to_be32(qpl_id),
 	};
 
-	err = gve_adminq_issue_cmd(priv, &cmd);
-	if (err)
-		return err;
+	if (gve_is_gqi(priv)) {
+		u32 qpl_id = priv->queue_format == GVE_GQI_RDA_FORMAT ?
+			GVE_RAW_ADDRESSING_QPL_ID : rx->data.qpl->id;
 
-	return 0;
+		cmd.create_rx_queue.rx_desc_ring_addr =
+			cpu_to_be64(rx->desc.bus),
+		cmd.create_rx_queue.rx_data_ring_addr =
+			cpu_to_be64(rx->data.data_bus),
+		cmd.create_rx_queue.index = cpu_to_be32(queue_index);
+		cmd.create_rx_queue.queue_page_list_id = cpu_to_be32(qpl_id);
+	} else {
+		cmd.create_rx_queue.rx_ring_size =
+			cpu_to_be16(priv->rx_desc_cnt);
+		cmd.create_rx_queue.rx_desc_ring_addr =
+			cpu_to_be64(rx->dqo.complq.bus);
+		cmd.create_rx_queue.rx_data_ring_addr =
+			cpu_to_be64(rx->dqo.bufq.bus);
+		cmd.create_rx_queue.packet_buffer_size =
+			cpu_to_be16(priv->data_buffer_size_dqo);
+		cmd.create_rx_queue.rx_buff_ring_size =
+			cpu_to_be16(priv->options_dqo_rda.rx_buff_ring_entries);
+		cmd.create_rx_queue.enable_rsc =
+			!!(priv->dev->features & NETIF_F_LRO);
+	}
+
+	return gve_adminq_issue_cmd(priv, &cmd);
 }
 
 int gve_adminq_create_rx_queues(struct gve_priv *priv, u32 num_queues)
@@ -512,17 +624,51 @@ int gve_adminq_destroy_rx_queues(struct gve_priv *priv, u32 num_queues)
 	return gve_adminq_kick_and_wait(priv);
 }
 
+static int gve_set_desc_cnt(struct gve_priv *priv,
+			    struct gve_device_descriptor *descriptor)
+{
+	priv->tx_desc_cnt = be16_to_cpu(descriptor->tx_queue_entries);
+	if (priv->tx_desc_cnt * sizeof(priv->tx->desc[0]) < PAGE_SIZE) {
+		dev_err(&priv->pdev->dev, "Tx desc count %d too low\n",
+			priv->tx_desc_cnt);
+		return -EINVAL;
+	}
+	priv->rx_desc_cnt = be16_to_cpu(descriptor->rx_queue_entries);
+	if (priv->rx_desc_cnt * sizeof(priv->rx->desc.desc_ring[0])
+	    < PAGE_SIZE) {
+		dev_err(&priv->pdev->dev, "Rx desc count %d too low\n",
+			priv->rx_desc_cnt);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int
+gve_set_desc_cnt_dqo(struct gve_priv *priv,
+		     const struct gve_device_descriptor *descriptor,
+		     const struct gve_device_option_dqo_rda *dev_op_dqo_rda)
+{
+	priv->tx_desc_cnt = be16_to_cpu(descriptor->tx_queue_entries);
+	priv->options_dqo_rda.tx_comp_ring_entries =
+		be16_to_cpu(dev_op_dqo_rda->tx_comp_ring_entries);
+	priv->rx_desc_cnt = be16_to_cpu(descriptor->rx_queue_entries);
+	priv->options_dqo_rda.rx_buff_ring_entries =
+		be16_to_cpu(dev_op_dqo_rda->rx_buff_ring_entries);
+
+	return 0;
+}
+
 int gve_adminq_describe_device(struct gve_priv *priv)
 {
+	struct gve_device_option_gqi_rda *dev_op_gqi_rda = NULL;
+	struct gve_device_option_gqi_qpl *dev_op_gqi_qpl = NULL;
+	struct gve_device_option_dqo_rda *dev_op_dqo_rda = NULL;
 	struct gve_device_descriptor *descriptor;
-	struct gve_device_option *dev_opt;
 	union gve_adminq_command cmd;
 	dma_addr_t descriptor_bus;
-	u16 num_options;
 	int err = 0;
 	u8 *mac;
 	u16 mtu;
-	int i;
 
 	memset(&cmd, 0, sizeof(cmd));
 	descriptor = dma_alloc_coherent(&priv->pdev->dev, PAGE_SIZE,
@@ -540,21 +686,41 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	if (err)
 		goto free_device_descriptor;
 
-	priv->tx_desc_cnt = be16_to_cpu(descriptor->tx_queue_entries);
-	if (priv->tx_desc_cnt * sizeof(priv->tx->desc[0]) < PAGE_SIZE) {
-		dev_err(&priv->pdev->dev, "Tx desc count %d too low\n", priv->tx_desc_cnt);
-		err = -EINVAL;
+	err = gve_process_device_options(priv, descriptor, &dev_op_gqi_rda,
+					 &dev_op_gqi_qpl, &dev_op_dqo_rda);
+	if (err)
 		goto free_device_descriptor;
+
+	/* If the GQI_RAW_ADDRESSING option is not enabled and the queue format
+	 * is not set to GqiRda, choose the queue format in a priority order:
+	 * DqoRda, GqiRda, GqiQpl. Use GqiQpl as default.
+	 */
+	if (priv->queue_format == GVE_GQI_RDA_FORMAT) {
+		dev_info(&priv->pdev->dev,
+			 "Driver is running with GQI RDA queue format.\n");
+	} else if (dev_op_dqo_rda) {
+		priv->queue_format = GVE_DQO_RDA_FORMAT;
+		dev_info(&priv->pdev->dev,
+			 "Driver is running with DQO RDA queue format.\n");
+	} else if (dev_op_gqi_rda) {
+		priv->queue_format = GVE_GQI_RDA_FORMAT;
+		dev_info(&priv->pdev->dev,
+			 "Driver is running with GQI RDA queue format.\n");
+	} else {
+		priv->queue_format = GVE_GQI_QPL_FORMAT;
+		dev_info(&priv->pdev->dev,
+			 "Driver is running with GQI QPL queue format.\n");
 	}
-	priv->rx_desc_cnt = be16_to_cpu(descriptor->rx_queue_entries);
-	if (priv->rx_desc_cnt * sizeof(priv->rx->desc.desc_ring[0])
-	    < PAGE_SIZE ||
-	    priv->rx_desc_cnt * sizeof(priv->rx->data.data_ring[0])
-	    < PAGE_SIZE) {
-		dev_err(&priv->pdev->dev, "Rx desc count %d too low\n", priv->rx_desc_cnt);
-		err = -EINVAL;
-		goto free_device_descriptor;
+	if (gve_is_gqi(priv)) {
+		err = gve_set_desc_cnt(priv, descriptor);
+	} else {
+		/* DQO supports LRO. */
+		priv->dev->hw_features |= NETIF_F_LRO;
+		err = gve_set_desc_cnt_dqo(priv, descriptor, dev_op_dqo_rda);
 	}
+	if (err)
+		goto free_device_descriptor;
+
 	priv->max_registered_pages =
 				be64_to_cpu(descriptor->max_registered_pages);
 	mtu = be16_to_cpu(descriptor->mtu);
@@ -570,32 +736,16 @@ int gve_adminq_describe_device(struct gve_priv *priv)
 	dev_info(&priv->pdev->dev, "MAC addr: %pM\n", mac);
 	priv->tx_pages_per_qpl = be16_to_cpu(descriptor->tx_pages_per_qpl);
 	priv->rx_data_slot_cnt = be16_to_cpu(descriptor->rx_pages_per_qpl);
-	if (priv->rx_data_slot_cnt < priv->rx_desc_cnt) {
+
+	if (gve_is_gqi(priv) && priv->rx_data_slot_cnt < priv->rx_desc_cnt) {
 		dev_err(&priv->pdev->dev, "rx_data_slot_cnt cannot be smaller than rx_desc_cnt, setting rx_desc_cnt down to %d.\n",
 			priv->rx_data_slot_cnt);
 		priv->rx_desc_cnt = priv->rx_data_slot_cnt;
 	}
 	priv->default_num_queues = be16_to_cpu(descriptor->default_num_queues);
-	dev_opt = (void *)(descriptor + 1);
-
-	num_options = be16_to_cpu(descriptor->num_device_options);
-	for (i = 0; i < num_options; i++) {
-		struct gve_device_option *next_opt;
-
-		next_opt = gve_get_next_option(descriptor, dev_opt);
-		if (!next_opt) {
-			dev_err(&priv->dev->dev,
-				"options exceed device_descriptor's total length.\n");
-			err = -EINVAL;
-			goto free_device_descriptor;
-		}
-
-		gve_parse_device_option(priv, descriptor, dev_opt);
-		dev_opt = next_opt;
-	}
 
 free_device_descriptor:
-	dma_free_coherent(&priv->pdev->dev, sizeof(*descriptor), descriptor,
+	dma_free_coherent(&priv->pdev->dev, PAGE_SIZE, descriptor,
 			  descriptor_bus);
 	return err;
 }
@@ -701,3 +851,41 @@ int gve_adminq_report_link_speed(struct gve_priv *priv)
 			  link_speed_region_bus);
 	return err;
 }
+
+int gve_adminq_get_ptype_map_dqo(struct gve_priv *priv,
+				 struct gve_ptype_lut *ptype_lut)
+{
+	struct gve_ptype_map *ptype_map;
+	union gve_adminq_command cmd;
+	dma_addr_t ptype_map_bus;
+	int err = 0;
+	int i;
+
+	memset(&cmd, 0, sizeof(cmd));
+	ptype_map = dma_alloc_coherent(&priv->pdev->dev, sizeof(*ptype_map),
+				       &ptype_map_bus, GFP_KERNEL);
+	if (!ptype_map)
+		return -ENOMEM;
+
+	cmd.opcode = cpu_to_be32(GVE_ADMINQ_GET_PTYPE_MAP);
+	cmd.get_ptype_map = (struct gve_adminq_get_ptype_map) {
+		.ptype_map_len = cpu_to_be64(sizeof(*ptype_map)),
+		.ptype_map_addr = cpu_to_be64(ptype_map_bus),
+	};
+
+	err = gve_adminq_execute_cmd(priv, &cmd);
+	if (err)
+		goto err;
+
+	/* Populate ptype_lut. */
+	for (i = 0; i < GVE_NUM_PTYPES; i++) {
+		ptype_lut->ptypes[i].l3_type =
+			ptype_map->ptypes[i].l3_type;
+		ptype_lut->ptypes[i].l4_type =
+			ptype_map->ptypes[i].l4_type;
+	}
+err:
+	dma_free_coherent(&priv->pdev->dev, sizeof(*ptype_map), ptype_map,
+			  ptype_map_bus);
+	return err;
+}

drivers/net/ethernet/google/gve/gve_adminq.h

 /* SPDX-License-Identifier: (GPL-2.0 OR MIT)
  * Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #ifndef _GVE_ADMINQ_H
@@ -22,7 +22,8 @@ enum gve_adminq_opcodes {
 	GVE_ADMINQ_DECONFIGURE_DEVICE_RESOURCES	= 0x9,
 	GVE_ADMINQ_SET_DRIVER_PARAMETER		= 0xB,
 	GVE_ADMINQ_REPORT_STATS			= 0xC,
-	GVE_ADMINQ_REPORT_LINK_SPEED	= 0xD
+	GVE_ADMINQ_REPORT_LINK_SPEED		= 0xD,
+	GVE_ADMINQ_GET_PTYPE_MAP		= 0xE,
 };
 
 /* Admin queue status codes */
@@ -82,14 +83,54 @@ static_assert(sizeof(struct gve_device_descriptor) == 40);
 struct gve_device_option {
 	__be16 option_id;
 	__be16 option_length;
-	__be32 feat_mask;
+	__be32 required_features_mask;
 };
 
 static_assert(sizeof(struct gve_device_option) == 8);
 
-#define GVE_DEV_OPT_ID_RAW_ADDRESSING 0x1
-#define GVE_DEV_OPT_LEN_RAW_ADDRESSING 0x0
-#define GVE_DEV_OPT_FEAT_MASK_RAW_ADDRESSING 0x0
+struct gve_device_option_gqi_rda {
+	__be32 supported_features_mask;
+};
+
+static_assert(sizeof(struct gve_device_option_gqi_rda) == 4);
+
+struct gve_device_option_gqi_qpl {
+	__be32 supported_features_mask;
+};
+
+static_assert(sizeof(struct gve_device_option_gqi_qpl) == 4);
+
+struct gve_device_option_dqo_rda {
+	__be32 supported_features_mask;
+	__be16 tx_comp_ring_entries;
+	__be16 rx_buff_ring_entries;
+};
+
+static_assert(sizeof(struct gve_device_option_dqo_rda) == 8);
+
+/* Terminology:
+ *
+ * RDA - Raw DMA Addressing - Buffers associated with SKBs are directly DMA
+ *       mapped and read/updated by the device.
+ *
+ * QPL - Queue Page Lists - Driver uses bounce buffers which are DMA mapped with
+ *       the device for read/write and data is copied from/to SKBs.
+ */
+enum gve_dev_opt_id {
+	GVE_DEV_OPT_ID_GQI_RAW_ADDRESSING = 0x1,
+	GVE_DEV_OPT_ID_GQI_RDA = 0x2,
+	GVE_DEV_OPT_ID_GQI_QPL = 0x3,
+	GVE_DEV_OPT_ID_DQO_RDA = 0x4,
+};
+
+enum gve_dev_opt_req_feat_mask {
+	GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RAW_ADDRESSING = 0x0,
+	GVE_DEV_OPT_REQ_FEAT_MASK_GQI_RDA = 0x0,
+	GVE_DEV_OPT_REQ_FEAT_MASK_GQI_QPL = 0x0,
+	GVE_DEV_OPT_REQ_FEAT_MASK_DQO_RDA = 0x0,
+};
+
+#define GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING 0x0
 
 struct gve_adminq_configure_device_resources {
 	__be64 counter_array;
@@ -98,9 +139,11 @@ struct gve_adminq_configure_device_resources {
 	__be32 num_irq_dbs;
 	__be32 irq_db_stride;
 	__be32 ntfy_blk_msix_base_idx;
+	u8 queue_format;
+	u8 padding[7];
 };
 
-static_assert(sizeof(struct gve_adminq_configure_device_resources) == 32);
+static_assert(sizeof(struct gve_adminq_configure_device_resources) == 40);
 
 struct gve_adminq_register_page_list {
 	__be32 page_list_id;
@@ -125,9 +168,13 @@ struct gve_adminq_create_tx_queue {
 	__be64 tx_ring_addr;
 	__be32 queue_page_list_id;
 	__be32 ntfy_id;
+	__be64 tx_comp_ring_addr;
+	__be16 tx_ring_size;
+	__be16 tx_comp_ring_size;
+	u8 padding[4];
 };
 
-static_assert(sizeof(struct gve_adminq_create_tx_queue) == 32);
+static_assert(sizeof(struct gve_adminq_create_tx_queue) == 48);
 
 struct gve_adminq_create_rx_queue {
 	__be32 queue_id;
@@ -138,10 +185,14 @@ struct gve_adminq_create_rx_queue {
 	__be64 rx_desc_ring_addr;
 	__be64 rx_data_ring_addr;
 	__be32 queue_page_list_id;
-	u8 padding[4];
+	__be16 rx_ring_size;
+	__be16 packet_buffer_size;
+	__be16 rx_buff_ring_size;
+	u8 enable_rsc;
+	u8 padding[5];
 };
 
-static_assert(sizeof(struct gve_adminq_create_rx_queue) == 48);
+static_assert(sizeof(struct gve_adminq_create_rx_queue) == 56);
 
 /* Queue resources that are shared with the device */
 struct gve_queue_resources {
@@ -226,6 +277,41 @@ enum gve_stat_names {
 	RX_DROPS_INVALID_CHECKSUM	= 68,
 };
 
+enum gve_l3_type {
+	/* Must be zero so zero initialized LUT is unknown. */
+	GVE_L3_TYPE_UNKNOWN = 0,
+	GVE_L3_TYPE_OTHER,
+	GVE_L3_TYPE_IPV4,
+	GVE_L3_TYPE_IPV6,
+};
+
+enum gve_l4_type {
+	/* Must be zero so zero initialized LUT is unknown. */
+	GVE_L4_TYPE_UNKNOWN = 0,
+	GVE_L4_TYPE_OTHER,
+	GVE_L4_TYPE_TCP,
+	GVE_L4_TYPE_UDP,
+	GVE_L4_TYPE_ICMP,
+	GVE_L4_TYPE_SCTP,
+};
+
+/* These are control path types for PTYPE which are the same as the data path
+ * types.
+ */
+struct gve_ptype_entry {
+	u8 l3_type;
+	u8 l4_type;
+};
+
+struct gve_ptype_map {
+	struct gve_ptype_entry ptypes[1 << 10]; /* PTYPES are always 10 bits. */
+};
+
+struct gve_adminq_get_ptype_map {
+	__be64 ptype_map_len;
+	__be64 ptype_map_addr;
+};
+
 union gve_adminq_command {
 	struct {
 		__be32 opcode;
@@ -243,6 +329,7 @@ union gve_adminq_command {
 			struct gve_adminq_set_driver_parameter set_driver_param;
 			struct gve_adminq_report_stats report_stats;
 			struct gve_adminq_report_link_speed report_link_speed;
+			struct gve_adminq_get_ptype_map get_ptype_map;
 		};
 	};
 	u8 reserved[64];
@@ -271,4 +358,9 @@ int gve_adminq_set_mtu(struct gve_priv *priv, u64 mtu);
 int gve_adminq_report_stats(struct gve_priv *priv, u64 stats_report_len,
 			    dma_addr_t stats_report_addr, u64 interval);
 int gve_adminq_report_link_speed(struct gve_priv *priv);
+
+struct gve_ptype_lut;
+int gve_adminq_get_ptype_map_dqo(struct gve_priv *priv,
+				 struct gve_ptype_lut *ptype_lut);
+
 #endif /* _GVE_ADMINQ_H */

drivers/net/ethernet/google/gve/gve_desc_dqo.h

+/* SPDX-License-Identifier: (GPL-2.0 OR MIT)
+ * Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+/* GVE DQO Descriptor formats */
+
+#ifndef _GVE_DESC_DQO_H_
+#define _GVE_DESC_DQO_H_
+
+#include <linux/build_bug.h>
+
+#define GVE_TX_MAX_HDR_SIZE_DQO 255
+#define GVE_TX_MIN_TSO_MSS_DQO 88
+
+#ifndef __LITTLE_ENDIAN_BITFIELD
+#error "Only little endian supported"
+#endif
+
+/* Basic TX descriptor (DTYPE 0x0C) */
+struct gve_tx_pkt_desc_dqo {
+	__le64 buf_addr;
+
+	/* Must be GVE_TX_PKT_DESC_DTYPE_DQO (0xc) */
+	u8 dtype: 5;
+
+	/* Denotes the last descriptor of a packet. */
+	u8 end_of_packet: 1;
+	u8 checksum_offload_enable: 1;
+
+	/* If set, will generate a descriptor completion for this descriptor. */
+	u8 report_event: 1;
+	u8 reserved0;
+	__le16 reserved1;
+
+	/* The TX completion associated with this packet will contain this tag.
+	 */
+	__le16 compl_tag;
+	u16 buf_size: 14;
+	u16 reserved2: 2;
+} __packed;
+static_assert(sizeof(struct gve_tx_pkt_desc_dqo) == 16);
+
+#define GVE_TX_PKT_DESC_DTYPE_DQO 0xc
+#define GVE_TX_MAX_BUF_SIZE_DQO ((16 * 1024) - 1)
+
+/* Maximum number of data descriptors allowed per packet, or per-TSO segment. */
+#define GVE_TX_MAX_DATA_DESCS 10
+
+/* Min gap between tail and head to avoid cacheline overlap */
+#define GVE_TX_MIN_DESC_PREVENT_CACHE_OVERLAP 4
+
+/* "report_event" on TX packet descriptors may only be reported on the last
+ * descriptor of a TX packet, and they must be spaced apart with at least this
+ * value.
+ */
+#define GVE_TX_MIN_RE_INTERVAL 32
+
+struct gve_tx_context_cmd_dtype {
+	u8 dtype: 5;
+	u8 tso: 1;
+	u8 reserved1: 2;
+
+	u8 reserved2;
+};
+
+static_assert(sizeof(struct gve_tx_context_cmd_dtype) == 2);
+
+/* TX Native TSO Context DTYPE (0x05)
+ *
+ * "flex" fields allow the driver to send additional packet context to HW.
+ */
+struct gve_tx_tso_context_desc_dqo {
+	/* The L4 payload bytes that should be segmented. */
+	u32 tso_total_len: 24;
+	u32 flex10: 8;
+
+	/* Max segment size in TSO excluding headers. */
+	u16 mss: 14;
+	u16 reserved: 2;
+
+	u8 header_len; /* Header length to use for TSO offload */
+	u8 flex11;
+	struct gve_tx_context_cmd_dtype cmd_dtype;
+	u8 flex0;
+	u8 flex5;
+	u8 flex6;
+	u8 flex7;
+	u8 flex8;
+	u8 flex9;
+} __packed;
+static_assert(sizeof(struct gve_tx_tso_context_desc_dqo) == 16);
+
+#define GVE_TX_TSO_CTX_DESC_DTYPE_DQO 0x5
+
+/* General context descriptor for sending metadata. */
+struct gve_tx_general_context_desc_dqo {
+	u8 flex4;
+	u8 flex5;
+	u8 flex6;
+	u8 flex7;
+	u8 flex8;
+	u8 flex9;
+	u8 flex10;
+	u8 flex11;
+	struct gve_tx_context_cmd_dtype cmd_dtype;
+	u16 reserved;
+	u8 flex0;
+	u8 flex1;
+	u8 flex2;
+	u8 flex3;
+} __packed;
+static_assert(sizeof(struct gve_tx_general_context_desc_dqo) == 16);
+
+#define GVE_TX_GENERAL_CTX_DESC_DTYPE_DQO 0x4
+
+/* Logical structure of metadata which is packed into context descriptor flex
+ * fields.
+ */
+struct gve_tx_metadata_dqo {
+	union {
+		struct {
+			u8 version;
+
+			/* If `skb->l4_hash` is set, this value should be
+			 * derived from `skb->hash`.
+			 *
+			 * A zero value means no l4_hash was associated with the
+			 * skb.
+			 */
+			u16 path_hash: 15;
+
+			/* Should be set to 1 if the flow associated with the
+			 * skb had a rehash from the TCP stack.
+			 */
+			u16 rehash_event: 1;
+		}  __packed;
+		u8 bytes[12];
+	};
+}  __packed;
+static_assert(sizeof(struct gve_tx_metadata_dqo) == 12);
+
+#define GVE_TX_METADATA_VERSION_DQO 0
+
+/* TX completion descriptor */
+struct gve_tx_compl_desc {
+	/* For types 0-4 this is the TX queue ID associated with this
+	 * completion.
+	 */
+	u16 id: 11;
+
+	/* See: GVE_COMPL_TYPE_DQO* */
+	u16 type: 3;
+	u16 reserved0: 1;
+
+	/* Flipped by HW to notify the descriptor is populated. */
+	u16 generation: 1;
+	union {
+		/* For descriptor completions, this is the last index fetched
+		 * by HW + 1.
+		 */
+		__le16 tx_head;
+
+		/* For packet completions, this is the completion tag set on the
+		 * TX packet descriptors.
+		 */
+		__le16 completion_tag;
+	};
+	__le32 reserved1;
+} __packed;
+static_assert(sizeof(struct gve_tx_compl_desc) == 8);
+
+#define GVE_COMPL_TYPE_DQO_PKT 0x2 /* Packet completion */
+#define GVE_COMPL_TYPE_DQO_DESC 0x4 /* Descriptor completion */
+#define GVE_COMPL_TYPE_DQO_MISS 0x1 /* Miss path completion */
+#define GVE_COMPL_TYPE_DQO_REINJECTION 0x3 /* Re-injection completion */
+
+/* Descriptor to post buffers to HW on buffer queue. */
+struct gve_rx_desc_dqo {
+	__le16 buf_id; /* ID returned in Rx completion descriptor */
+	__le16 reserved0;
+	__le32 reserved1;
+	__le64 buf_addr; /* DMA address of the buffer */
+	__le64 header_buf_addr;
+	__le64 reserved2;
+} __packed;
+static_assert(sizeof(struct gve_rx_desc_dqo) == 32);
+
+/* Descriptor for HW to notify SW of new packets received on RX queue. */
+struct gve_rx_compl_desc_dqo {
+	/* Must be 1 */
+	u8 rxdid: 4;
+	u8 reserved0: 4;
+
+	/* Packet originated from this system rather than the network. */
+	u8 loopback: 1;
+	/* Set when IPv6 packet contains a destination options header or routing
+	 * header.
+	 */
+	u8 ipv6_ex_add: 1;
+	/* Invalid packet was received. */
+	u8 rx_error: 1;
+	u8 reserved1: 5;
+
+	u16 packet_type: 10;
+	u16 ip_hdr_err: 1;
+	u16 udp_len_err: 1;
+	u16 raw_cs_invalid: 1;
+	u16 reserved2: 3;
+
+	u16 packet_len: 14;
+	/* Flipped by HW to notify the descriptor is populated. */
+	u16 generation: 1;
+	/* Should be zero. */
+	u16 buffer_queue_id: 1;
+
+	u16 header_len: 10;
+	u16 rsc: 1;
+	u16 split_header: 1;
+	u16 reserved3: 4;
+
+	u8 descriptor_done: 1;
+	u8 end_of_packet: 1;
+	u8 header_buffer_overflow: 1;
+	u8 l3_l4_processed: 1;
+	u8 csum_ip_err: 1;
+	u8 csum_l4_err: 1;
+	u8 csum_external_ip_err: 1;
+	u8 csum_external_udp_err: 1;
+
+	u8 status_error1;
+
+	__le16 reserved5;
+	__le16 buf_id; /* Buffer ID which was sent on the buffer queue. */
+
+	union {
+		/* Packet checksum. */
+		__le16 raw_cs;
+		/* Segment length for RSC packets. */
+		__le16 rsc_seg_len;
+	};
+	__le32 hash;
+	__le32 reserved6;
+	__le64 reserved7;
+} __packed;
+
+static_assert(sizeof(struct gve_rx_compl_desc_dqo) == 32);
+
+/* Ringing the doorbell too often can hurt performance.
+ *
+ * HW requires this value to be at least 8.
+ */
+#define GVE_RX_BUF_THRESH_DQO 32
+
+#endif /* _GVE_DESC_DQO_H_ */

drivers/net/ethernet/google/gve/gve_dqo.h

+/* SPDX-License-Identifier: (GPL-2.0 OR MIT)
+ * Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+#ifndef _GVE_DQO_H_
+#define _GVE_DQO_H_
+
+#include "gve_adminq.h"
+
+#define GVE_ITR_ENABLE_BIT_DQO BIT(0)
+#define GVE_ITR_CLEAR_PBA_BIT_DQO BIT(1)
+#define GVE_ITR_NO_UPDATE_DQO (3 << 3)
+
+#define GVE_ITR_INTERVAL_DQO_SHIFT 5
+#define GVE_ITR_INTERVAL_DQO_MASK ((1 << 12) - 1)
+
+#define GVE_TX_IRQ_RATELIMIT_US_DQO 50
+#define GVE_RX_IRQ_RATELIMIT_US_DQO 20
+
+/* Timeout in seconds to wait for a reinjection completion after receiving
+ * its corresponding miss completion.
+ */
+#define GVE_REINJECT_COMPL_TIMEOUT 1
+
+/* Timeout in seconds to deallocate the completion tag for a packet that was
+ * prematurely freed for not receiving a valid completion. This should be large
+ * enough to rule out the possibility of receiving the corresponding valid
+ * completion after this interval.
+ */
+#define GVE_DEALLOCATE_COMPL_TIMEOUT 60
+
+netdev_tx_t gve_tx_dqo(struct sk_buff *skb, struct net_device *dev);
+bool gve_tx_poll_dqo(struct gve_notify_block *block, bool do_clean);
+int gve_rx_poll_dqo(struct gve_notify_block *block, int budget);
+int gve_tx_alloc_rings_dqo(struct gve_priv *priv);
+void gve_tx_free_rings_dqo(struct gve_priv *priv);
+int gve_rx_alloc_rings_dqo(struct gve_priv *priv);
+void gve_rx_free_rings_dqo(struct gve_priv *priv);
+int gve_clean_tx_done_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
+			  struct napi_struct *napi);
+void gve_rx_post_buffers_dqo(struct gve_rx_ring *rx);
+void gve_rx_write_doorbell_dqo(const struct gve_priv *priv, int queue_idx);
+
+static inline void
+gve_tx_put_doorbell_dqo(const struct gve_priv *priv,
+			const struct gve_queue_resources *q_resources, u32 val)
+{
+	u64 index;
+
+	index = be32_to_cpu(q_resources->db_index);
+	iowrite32(val, &priv->db_bar2[index]);
+}
+
+/* Builds register value to write to DQO IRQ doorbell to enable with specified
+ * ratelimit.
+ */
+static inline u32 gve_set_itr_ratelimit_dqo(u32 ratelimit_us)
+{
+	u32 result = GVE_ITR_ENABLE_BIT_DQO;
+
+	/* Interval has 2us granularity. */
+	ratelimit_us >>= 1;
+
+	ratelimit_us &= GVE_ITR_INTERVAL_DQO_MASK;
+	result |= (ratelimit_us << GVE_ITR_INTERVAL_DQO_SHIFT);
+
+	return result;
+}
+
+static inline void
+gve_write_irq_doorbell_dqo(const struct gve_priv *priv,
+			   const struct gve_notify_block *block, u32 val)
+{
+	u32 index = be32_to_cpu(block->irq_db_index);
+
+	iowrite32(val, &priv->db_bar2[index]);
+}
+
+#endif /* _GVE_DQO_H_ */

drivers/net/ethernet/google/gve/gve_ethtool.c

 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
 /* Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #include <linux/ethtool.h>
@@ -311,8 +311,16 @@ gve_get_ethtool_stats(struct net_device *netdev,
 		for (ring = 0; ring < priv->tx_cfg.num_queues; ring++) {
 			struct gve_tx_ring *tx = &priv->tx[ring];
 
+			if (gve_is_gqi(priv)) {
 				data[i++] = tx->req;
 				data[i++] = tx->done;
+			} else {
+				/* DQO doesn't currently support
+				 * posted/completed descriptor counts;
+				 */
+				data[i++] = 0;
+				data[i++] = 0;
+			}
 			do {
 				start =
 				  u64_stats_fetch_begin(&priv->tx[ring].statss);
@@ -453,11 +461,16 @@ static int gve_set_tunable(struct net_device *netdev,
 
 	switch (etuna->id) {
 	case ETHTOOL_RX_COPYBREAK:
+	{
+		u32 max_copybreak = gve_is_gqi(priv) ?
+			(PAGE_SIZE / 2) : priv->data_buffer_size_dqo;
+
 		len = *(u32 *)value;
-		if (len > PAGE_SIZE / 2)
+		if (len > max_copybreak)
 			return -EINVAL;
 		priv->rx_copybreak = len;
 		return 0;
+	}
 	default:
 		return -EOPNOTSUPP;
 	}

drivers/net/ethernet/google/gve/gve_main.c

 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
 /* Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #include <linux/cpumask.h>
@@ -14,6 +14,7 @@
 #include <linux/workqueue.h>
 #include <net/sch_generic.h>
 #include "gve.h"
+#include "gve_dqo.h"
 #include "gve_adminq.h"
 #include "gve_register.h"
 
@@ -26,6 +27,16 @@
 const char gve_version_str[] = GVE_VERSION;
 static const char gve_version_prefix[] = GVE_VERSION_PREFIX;
 
+static netdev_tx_t gve_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct gve_priv *priv = netdev_priv(dev);
+
+	if (gve_is_gqi(priv))
+		return gve_tx(skb, dev);
+	else
+		return gve_tx_dqo(skb, dev);
+}
+
 static void gve_get_stats(struct net_device *dev, struct rtnl_link_stats64 *s)
 {
 	struct gve_priv *priv = netdev_priv(dev);
@@ -155,6 +166,15 @@ static irqreturn_t gve_intr(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t gve_intr_dqo(int irq, void *arg)
+{
+	struct gve_notify_block *block = arg;
+
+	/* Interrupts are automatically masked */
+	napi_schedule_irqoff(&block->napi);
+	return IRQ_HANDLED;
+}
+
 static int gve_napi_poll(struct napi_struct *napi, int budget)
 {
 	struct gve_notify_block *block;
@@ -191,6 +211,54 @@ static int gve_napi_poll(struct napi_struct *napi, int budget)
 	return 0;
 }
 
+static int gve_napi_poll_dqo(struct napi_struct *napi, int budget)
+{
+	struct gve_notify_block *block =
+		container_of(napi, struct gve_notify_block, napi);
+	struct gve_priv *priv = block->priv;
+	bool reschedule = false;
+	int work_done = 0;
+
+	/* Clear PCI MSI-X Pending Bit Array (PBA)
+	 *
+	 * This bit is set if an interrupt event occurs while the vector is
+	 * masked. If this bit is set and we reenable the interrupt, it will
+	 * fire again. Since we're just about to poll the queue state, we don't
+	 * need it to fire again.
+	 *
+	 * Under high softirq load, it's possible that the interrupt condition
+	 * is triggered twice before we got the chance to process it.
+	 */
+	gve_write_irq_doorbell_dqo(priv, block,
+				   GVE_ITR_NO_UPDATE_DQO | GVE_ITR_CLEAR_PBA_BIT_DQO);
+
+	if (block->tx)
+		reschedule |= gve_tx_poll_dqo(block, /*do_clean=*/true);
+
+	if (block->rx) {
+		work_done = gve_rx_poll_dqo(block, budget);
+		reschedule |= work_done == budget;
+	}
+
+	if (reschedule)
+		return budget;
+
+	if (likely(napi_complete_done(napi, work_done))) {
+		/* Enable interrupts again.
+		 *
+		 * We don't need to repoll afterwards because HW supports the
+		 * PCI MSI-X PBA feature.
+		 *
+		 * Another interrupt would be triggered if a new event came in
+		 * since the last one.
+		 */
+		gve_write_irq_doorbell_dqo(priv, block,
+					   GVE_ITR_NO_UPDATE_DQO | GVE_ITR_ENABLE_BIT_DQO);
+	}
+
+	return work_done;
+}
+
 static int gve_alloc_notify_blocks(struct gve_priv *priv)
 {
 	int num_vecs_requested = priv->num_ntfy_blks + 1;
@@ -264,7 +332,8 @@ static int gve_alloc_notify_blocks(struct gve_priv *priv)
 			 name, i);
 		block->priv = priv;
 		err = request_irq(priv->msix_vectors[msix_idx].vector,
-				  gve_intr, 0, block->name, block);
+				  gve_is_gqi(priv) ? gve_intr : gve_intr_dqo,
+				  0, block->name, block);
 		if (err) {
 			dev_err(&priv->pdev->dev,
 				"Failed to receive msix vector %d\n", i);
@@ -346,6 +415,22 @@ static int gve_setup_device_resources(struct gve_priv *priv)
 		err = -ENXIO;
 		goto abort_with_stats_report;
 	}
+
+	if (priv->queue_format == GVE_DQO_RDA_FORMAT) {
+		priv->ptype_lut_dqo = kvzalloc(sizeof(*priv->ptype_lut_dqo),
+					       GFP_KERNEL);
+		if (!priv->ptype_lut_dqo) {
+			err = -ENOMEM;
+			goto abort_with_stats_report;
+		}
+		err = gve_adminq_get_ptype_map_dqo(priv, priv->ptype_lut_dqo);
+		if (err) {
+			dev_err(&priv->pdev->dev,
+				"Failed to get ptype map: err=%d\n", err);
+			goto abort_with_ptype_lut;
+		}
+	}
+
 	err = gve_adminq_report_stats(priv, priv->stats_report_len,
 				      priv->stats_report_bus,
 				      GVE_STATS_REPORT_TIMER_PERIOD);
@@ -354,12 +439,17 @@ static int gve_setup_device_resources(struct gve_priv *priv)
 			"Failed to report stats: err=%d\n", err);
 	gve_set_device_resources_ok(priv);
 	return 0;
+
+abort_with_ptype_lut:
+	kvfree(priv->ptype_lut_dqo);
+	priv->ptype_lut_dqo = NULL;
 abort_with_stats_report:
 	gve_free_stats_report(priv);
 abort_with_ntfy_blocks:
 	gve_free_notify_blocks(priv);
 abort_with_counter:
 	gve_free_counter_array(priv);
+
 	return err;
 }
 
@@ -386,17 +476,22 @@ static void gve_teardown_device_resources(struct gve_priv *priv)
 			gve_trigger_reset(priv);
 		}
 	}
+
+	kvfree(priv->ptype_lut_dqo);
+	priv->ptype_lut_dqo = NULL;
+
 	gve_free_counter_array(priv);
 	gve_free_notify_blocks(priv);
 	gve_free_stats_report(priv);
 	gve_clear_device_resources_ok(priv);
 }
 
-static void gve_add_napi(struct gve_priv *priv, int ntfy_idx)
+static void gve_add_napi(struct gve_priv *priv, int ntfy_idx,
+			 int (*gve_poll)(struct napi_struct *, int))
 {
 	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
 
-	netif_napi_add(priv->dev, &block->napi, gve_napi_poll,
+	netif_napi_add(priv->dev, &block->napi, gve_poll,
 		       NAPI_POLL_WEIGHT);
 }
 
@@ -476,31 +571,75 @@ static int gve_create_rings(struct gve_priv *priv)
 	netif_dbg(priv, drv, priv->dev, "created %d rx queues\n",
 		  priv->rx_cfg.num_queues);
 
+	if (gve_is_gqi(priv)) {
 		/* Rx data ring has been prefilled with packet buffers at queue
 		 * allocation time.
-	 * Write the doorbell to provide descriptor slots and packet buffers
-	 * to the NIC.
+		 *
+		 * Write the doorbell to provide descriptor slots and packet
+		 * buffers to the NIC.
 		 */
 		for (i = 0; i < priv->rx_cfg.num_queues; i++)
 			gve_rx_write_doorbell(priv, &priv->rx[i]);
+	} else {
+		for (i = 0; i < priv->rx_cfg.num_queues; i++) {
+			/* Post buffers and ring doorbell. */
+			gve_rx_post_buffers_dqo(&priv->rx[i]);
+		}
+	}
 
 	return 0;
 }
 
+static void add_napi_init_sync_stats(struct gve_priv *priv,
+				     int (*napi_poll)(struct napi_struct *napi,
+						      int budget))
+{
+	int i;
+
+	/* Add tx napi & init sync stats*/
+	for (i = 0; i < priv->tx_cfg.num_queues; i++) {
+		int ntfy_idx = gve_tx_idx_to_ntfy(priv, i);
+
+		u64_stats_init(&priv->tx[i].statss);
+		priv->tx[i].ntfy_id = ntfy_idx;
+		gve_add_napi(priv, ntfy_idx, napi_poll);
+	}
+	/* Add rx napi  & init sync stats*/
+	for (i = 0; i < priv->rx_cfg.num_queues; i++) {
+		int ntfy_idx = gve_rx_idx_to_ntfy(priv, i);
+
+		u64_stats_init(&priv->rx[i].statss);
+		priv->rx[i].ntfy_id = ntfy_idx;
+		gve_add_napi(priv, ntfy_idx, napi_poll);
+	}
+}
+
+static void gve_tx_free_rings(struct gve_priv *priv)
+{
+	if (gve_is_gqi(priv)) {
+		gve_tx_free_rings_gqi(priv);
+	} else {
+		gve_tx_free_rings_dqo(priv);
+	}
+}
+
 static int gve_alloc_rings(struct gve_priv *priv)
 {
-	int ntfy_idx;
 	int err;
-	int i;
 
 	/* Setup tx rings */
 	priv->tx = kvzalloc(priv->tx_cfg.num_queues * sizeof(*priv->tx),
 			    GFP_KERNEL);
 	if (!priv->tx)
 		return -ENOMEM;
+
+	if (gve_is_gqi(priv))
 		err = gve_tx_alloc_rings(priv);
+	else
+		err = gve_tx_alloc_rings_dqo(priv);
 	if (err)
 		goto free_tx;
+
 	/* Setup rx rings */
 	priv->rx = kvzalloc(priv->rx_cfg.num_queues * sizeof(*priv->rx),
 			    GFP_KERNEL);
@@ -508,21 +647,18 @@ static int gve_alloc_rings(struct gve_priv *priv)
 		err = -ENOMEM;
 		goto free_tx_queue;
 	}
+
+	if (gve_is_gqi(priv))
 		err = gve_rx_alloc_rings(priv);
+	else
+		err = gve_rx_alloc_rings_dqo(priv);
 	if (err)
 		goto free_rx;
-	/* Add tx napi & init sync stats*/
-	for (i = 0; i < priv->tx_cfg.num_queues; i++) {
-		u64_stats_init(&priv->tx[i].statss);
-		ntfy_idx = gve_tx_idx_to_ntfy(priv, i);
-		gve_add_napi(priv, ntfy_idx);
-	}
-	/* Add rx napi  & init sync stats*/
-	for (i = 0; i < priv->rx_cfg.num_queues; i++) {
-		u64_stats_init(&priv->rx[i].statss);
-		ntfy_idx = gve_rx_idx_to_ntfy(priv, i);
-		gve_add_napi(priv, ntfy_idx);
-	}
+
+	if (gve_is_gqi(priv))
+		add_napi_init_sync_stats(priv, gve_napi_poll);
+	else
+		add_napi_init_sync_stats(priv, gve_napi_poll_dqo);
 
 	return 0;
 
@@ -560,6 +696,14 @@ static int gve_destroy_rings(struct gve_priv *priv)
 	return 0;
 }
 
+static inline void gve_rx_free_rings(struct gve_priv *priv)
+{
+	if (gve_is_gqi(priv))
+		gve_rx_free_rings_gqi(priv);
+	else
+		gve_rx_free_rings_dqo(priv);
+}
+
 static void gve_free_rings(struct gve_priv *priv)
 {
 	int ntfy_idx;
@@ -681,7 +825,7 @@ static int gve_alloc_qpls(struct gve_priv *priv)
 	int err;
 
 	/* Raw addressing means no QPLs */
-	if (priv->raw_addressing)
+	if (priv->queue_format == GVE_GQI_RDA_FORMAT)
 		return 0;
 
 	priv->qpls = kvzalloc(num_qpls * sizeof(*priv->qpls), GFP_KERNEL);
@@ -725,7 +869,7 @@ static void gve_free_qpls(struct gve_priv *priv)
 	int i;
 
 	/* Raw addressing means no QPLs */
-	if (priv->raw_addressing)
+	if (priv->queue_format == GVE_GQI_RDA_FORMAT)
 		return;
 
 	kvfree(priv->qpl_cfg.qpl_id_map);
@@ -759,6 +903,7 @@ static int gve_open(struct net_device *dev)
 	err = gve_alloc_qpls(priv);
 	if (err)
 		return err;
+
 	err = gve_alloc_rings(priv);
 	if (err)
 		goto free_qpls;
@@ -773,9 +918,17 @@ static int gve_open(struct net_device *dev)
 	err = gve_register_qpls(priv);
 	if (err)
 		goto reset;
+
+	if (!gve_is_gqi(priv)) {
+		/* Hard code this for now. This may be tuned in the future for
+		 * performance.
+		 */
+		priv->data_buffer_size_dqo = GVE_RX_BUFFER_SIZE_DQO;
+	}
 	err = gve_create_rings(priv);
 	if (err)
 		goto reset;
+
 	gve_set_device_rings_ok(priv);
 
 	if (gve_get_report_stats(priv))
@@ -924,14 +1077,26 @@ static void gve_turnup(struct gve_priv *priv)
 		struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
 
 		napi_enable(&block->napi);
+		if (gve_is_gqi(priv)) {
 			iowrite32be(0, gve_irq_doorbell(priv, block));
+		} else {
+			u32 val = gve_set_itr_ratelimit_dqo(GVE_TX_IRQ_RATELIMIT_US_DQO);
+
+			gve_write_irq_doorbell_dqo(priv, block, val);
+		}
 	}
 	for (idx = 0; idx < priv->rx_cfg.num_queues; idx++) {
 		int ntfy_idx = gve_rx_idx_to_ntfy(priv, idx);
 		struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
 
 		napi_enable(&block->napi);
+		if (gve_is_gqi(priv)) {
 			iowrite32be(0, gve_irq_doorbell(priv, block));
+		} else {
+			u32 val = gve_set_itr_ratelimit_dqo(GVE_RX_IRQ_RATELIMIT_US_DQO);
+
+			gve_write_irq_doorbell_dqo(priv, block, val);
+		}
 	}
 
 	gve_set_napi_enabled(priv);
@@ -945,12 +1110,49 @@ static void gve_tx_timeout(struct net_device *dev, unsigned int txqueue)
 	priv->tx_timeo_cnt++;
 }
 
+static int gve_set_features(struct net_device *netdev,
+			    netdev_features_t features)
+{
+	const netdev_features_t orig_features = netdev->features;
+	struct gve_priv *priv = netdev_priv(netdev);
+	int err;
+
+	if ((netdev->features & NETIF_F_LRO) != (features & NETIF_F_LRO)) {
+		netdev->features ^= NETIF_F_LRO;
+		if (netif_carrier_ok(netdev)) {
+			/* To make this process as simple as possible we
+			 * teardown the device, set the new configuration,
+			 * and then bring the device up again.
+			 */
+			err = gve_close(netdev);
+			/* We have already tried to reset in close, just fail
+			 * at this point.
+			 */
+			if (err)
+				goto err;
+
+			err = gve_open(netdev);
+			if (err)
+				goto err;
+		}
+	}
+
+	return 0;
+err:
+	/* Reverts the change on error. */
+	netdev->features = orig_features;
+	netif_err(priv, drv, netdev,
+		  "Set features failed! !!! DISABLING ALL QUEUES !!!\n");
+	return err;
+}
+
 static const struct net_device_ops gve_netdev_ops = {
-	.ndo_start_xmit		=	gve_tx,
+	.ndo_start_xmit		=	gve_start_xmit,
 	.ndo_open		=	gve_open,
 	.ndo_stop		=	gve_close,
 	.ndo_get_stats64	=	gve_get_stats,
 	.ndo_tx_timeout         =       gve_tx_timeout,
+	.ndo_set_features	=	gve_set_features,
 };
 
 static void gve_handle_status(struct gve_priv *priv, u32 status)
@@ -994,6 +1196,15 @@ void gve_handle_report_stats(struct gve_priv *priv)
 	/* tx stats */
 	if (priv->tx) {
 		for (idx = 0; idx < priv->tx_cfg.num_queues; idx++) {
+			u32 last_completion = 0;
+			u32 tx_frames = 0;
+
+			/* DQO doesn't currently support these metrics. */
+			if (gve_is_gqi(priv)) {
+				last_completion = priv->tx[idx].done;
+				tx_frames = priv->tx[idx].req;
+			}
+
 			do {
 				start = u64_stats_fetch_begin(&priv->tx[idx].statss);
 				tx_bytes = priv->tx[idx].bytes_done;
@@ -1010,7 +1221,7 @@ void gve_handle_report_stats(struct gve_priv *priv)
 			};
 			stats[stats_idx++] = (struct stats) {
 				.stat_name = cpu_to_be32(TX_FRAMES_SENT),
-				.value = cpu_to_be64(priv->tx[idx].req),
+				.value = cpu_to_be64(tx_frames),
 				.queue_id = cpu_to_be32(idx),
 			};
 			stats[stats_idx++] = (struct stats) {
@@ -1020,7 +1231,7 @@ void gve_handle_report_stats(struct gve_priv *priv)
 			};
 			stats[stats_idx++] = (struct stats) {
 				.stat_name = cpu_to_be32(TX_LAST_COMPLETION_PROCESSED),
-				.value = cpu_to_be64(priv->tx[idx].done),
+				.value = cpu_to_be64(last_completion),
 				.queue_id = cpu_to_be32(idx),
 			};
 		}
@@ -1088,7 +1299,7 @@ static int gve_init_priv(struct gve_priv *priv, bool skip_describe_device)
 	if (skip_describe_device)
 		goto setup_device;
 
-	priv->raw_addressing = false;
+	priv->queue_format = GVE_QUEUE_FORMAT_UNSPECIFIED;
 	/* Get the initial information we need from the device */
 	err = gve_adminq_describe_device(priv);
 	if (err) {
@@ -1096,7 +1307,7 @@ static int gve_init_priv(struct gve_priv *priv, bool skip_describe_device)
 			"Could not get device information: err=%d\n", err);
 		goto err;
 	}
-	if (priv->dev->max_mtu > PAGE_SIZE) {
+	if (gve_is_gqi(priv) && priv->dev->max_mtu > PAGE_SIZE) {
 		priv->dev->max_mtu = PAGE_SIZE;
 		err = gve_adminq_set_mtu(priv, priv->dev->mtu);
 		if (err) {
@@ -1307,7 +1518,12 @@ static int gve_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	pci_set_drvdata(pdev, dev);
 	dev->ethtool_ops = &gve_ethtool_ops;
 	dev->netdev_ops = &gve_netdev_ops;
-	/* advertise features */
+
+	/* Set default and supported features.
+	 *
+	 * Features might be set in other locations as well (such as
+	 * `gve_adminq_describe_device`).
+	 */
 	dev->hw_features = NETIF_F_HIGHDMA;
 	dev->hw_features |= NETIF_F_SG;
 	dev->hw_features |= NETIF_F_HW_CSUM;
@@ -1352,6 +1568,7 @@ static int gve_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto abort_with_wq;
 
 	dev_info(&pdev->dev, "GVE version %s\n", gve_version_str);
+	dev_info(&pdev->dev, "GVE queue format %d\n", (int)priv->queue_format);
 	gve_clear_probe_in_progress(priv);
 	queue_work(priv->gve_wq, &priv->service_task);
 	return 0;

drivers/net/ethernet/google/gve/gve_rx.c

 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
 /* Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #include "gve.h"
 #include "gve_adminq.h"
+#include "gve_utils.h"
 #include <linux/etherdevice.h>
 
-static void gve_rx_remove_from_block(struct gve_priv *priv, int queue_idx)
-{
-	struct gve_notify_block *block =
-			&priv->ntfy_blocks[gve_rx_idx_to_ntfy(priv, queue_idx)];
-
-	block->rx = NULL;
-}
-
 static void gve_rx_free_buffer(struct device *dev,
 			       struct gve_rx_slot_page_info *page_info,
 			       union gve_rx_data_slot *data_slot)
@@ -137,16 +130,6 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
 	return err;
 }
 
-static void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx)
-{
-	u32 ntfy_idx = gve_rx_idx_to_ntfy(priv, queue_idx);
-	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
-	struct gve_rx_ring *rx = &priv->rx[queue_idx];
-
-	block->rx = rx;
-	rx->ntfy_id = ntfy_idx;
-}
-
 static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
 {
 	struct gve_rx_ring *rx = &priv->rx[idx];
@@ -165,7 +148,7 @@ static int gve_rx_alloc_ring(struct gve_priv *priv, int idx)
 
 	slots = priv->rx_data_slot_cnt;
 	rx->mask = slots - 1;
-	rx->data.raw_addressing = priv->raw_addressing;
+	rx->data.raw_addressing = priv->queue_format == GVE_GQI_RDA_FORMAT;
 
 	/* alloc rx data ring */
 	bytes = sizeof(*rx->data.data_ring) * slots;
@@ -255,7 +238,7 @@ int gve_rx_alloc_rings(struct gve_priv *priv)
 	return err;
 }
 
-void gve_rx_free_rings(struct gve_priv *priv)
+void gve_rx_free_rings_gqi(struct gve_priv *priv)
 {
 	int i;
 
@@ -279,27 +262,6 @@ static enum pkt_hash_types gve_rss_type(__be16 pkt_flags)
 	return PKT_HASH_TYPE_L2;
 }
 
-static struct sk_buff *gve_rx_copy(struct net_device *dev,
-				   struct napi_struct *napi,
-				   struct gve_rx_slot_page_info *page_info,
-				   u16 len)
-{
-	struct sk_buff *skb = napi_alloc_skb(napi, len);
-	void *va = page_info->page_address + GVE_RX_PAD +
-		   (page_info->page_offset ? PAGE_SIZE / 2 : 0);
-
-	if (unlikely(!skb))
-		return NULL;
-
-	__skb_put(skb, len);
-
-	skb_copy_to_linear_data(skb, va, len);
-
-	skb->protocol = eth_type_trans(skb, dev);
-
-	return skb;
-}
-
 static struct sk_buff *gve_rx_add_frags(struct napi_struct *napi,
 					struct gve_rx_slot_page_info *page_info,
 					u16 len)
@@ -310,7 +272,7 @@ static struct sk_buff *gve_rx_add_frags(struct napi_struct *napi,
 		return NULL;
 
 	skb_add_rx_frag(skb, 0, page_info->page,
-			(page_info->page_offset ? PAGE_SIZE / 2 : 0) +
+			page_info->page_offset +
 			GVE_RX_PAD, len, PAGE_SIZE / 2);
 
 	return skb;
@@ -321,7 +283,7 @@ static void gve_rx_flip_buff(struct gve_rx_slot_page_info *page_info, __be64 *sl
 	const __be64 offset = cpu_to_be64(PAGE_SIZE / 2);
 
 	/* "flip" to other packet buffer on this page */
-	page_info->page_offset ^= 0x1;
+	page_info->page_offset ^= PAGE_SIZE / 2;
 	*(slot_addr) ^= offset;
 }
 
@@ -388,7 +350,7 @@ gve_rx_qpl(struct device *dev, struct net_device *netdev,
 			gve_rx_flip_buff(page_info, &data_slot->qpl_offset);
 		}
 	} else {
-		skb = gve_rx_copy(netdev, napi, page_info, len);
+		skb = gve_rx_copy(netdev, napi, page_info, len, GVE_RX_PAD);
 		if (skb) {
 			u64_stats_update_begin(&rx->statss);
 			rx->rx_copied_pkt++;
@@ -430,7 +392,7 @@ static bool gve_rx(struct gve_rx_ring *rx, struct gve_rx_desc *rx_desc,
 
 	if (len <= priv->rx_copybreak) {
 		/* Just copy small packets */
-		skb = gve_rx_copy(dev, napi, page_info, len);
+		skb = gve_rx_copy(dev, napi, page_info, len, GVE_RX_PAD);
 		u64_stats_update_begin(&rx->statss);
 		rx->rx_copied_pkt++;
 		rx->rx_copybreak_pkt++;

drivers/net/ethernet/google/gve/gve_rx_dqo.c

+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+#include "gve.h"
+#include "gve_dqo.h"
+#include "gve_adminq.h"
+#include "gve_utils.h"
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/ip6_checksum.h>
+#include <net/ipv6.h>
+#include <net/tcp.h>
+
+static int gve_buf_ref_cnt(struct gve_rx_buf_state_dqo *bs)
+{
+	return page_count(bs->page_info.page) - bs->page_info.pagecnt_bias;
+}
+
+static void gve_free_page_dqo(struct gve_priv *priv,
+			      struct gve_rx_buf_state_dqo *bs)
+{
+	page_ref_sub(bs->page_info.page, bs->page_info.pagecnt_bias - 1);
+	gve_free_page(&priv->pdev->dev, bs->page_info.page, bs->addr,
+		      DMA_FROM_DEVICE);
+	bs->page_info.page = NULL;
+}
+
+static struct gve_rx_buf_state_dqo *gve_alloc_buf_state(struct gve_rx_ring *rx)
+{
+	struct gve_rx_buf_state_dqo *buf_state;
+	s16 buffer_id;
+
+	buffer_id = rx->dqo.free_buf_states;
+	if (unlikely(buffer_id == -1))
+		return NULL;
+
+	buf_state = &rx->dqo.buf_states[buffer_id];
+
+	/* Remove buf_state from free list */
+	rx->dqo.free_buf_states = buf_state->next;
+
+	/* Point buf_state to itself to mark it as allocated */
+	buf_state->next = buffer_id;
+
+	return buf_state;
+}
+
+static bool gve_buf_state_is_allocated(struct gve_rx_ring *rx,
+				       struct gve_rx_buf_state_dqo *buf_state)
+{
+	s16 buffer_id = buf_state - rx->dqo.buf_states;
+
+	return buf_state->next == buffer_id;
+}
+
+static void gve_free_buf_state(struct gve_rx_ring *rx,
+			       struct gve_rx_buf_state_dqo *buf_state)
+{
+	s16 buffer_id = buf_state - rx->dqo.buf_states;
+
+	buf_state->next = rx->dqo.free_buf_states;
+	rx->dqo.free_buf_states = buffer_id;
+}
+
+static struct gve_rx_buf_state_dqo *
+gve_dequeue_buf_state(struct gve_rx_ring *rx, struct gve_index_list *list)
+{
+	struct gve_rx_buf_state_dqo *buf_state;
+	s16 buffer_id;
+
+	buffer_id = list->head;
+	if (unlikely(buffer_id == -1))
+		return NULL;
+
+	buf_state = &rx->dqo.buf_states[buffer_id];
+
+	/* Remove buf_state from list */
+	list->head = buf_state->next;
+	if (buf_state->next == -1)
+		list->tail = -1;
+
+	/* Point buf_state to itself to mark it as allocated */
+	buf_state->next = buffer_id;
+
+	return buf_state;
+}
+
+static void gve_enqueue_buf_state(struct gve_rx_ring *rx,
+				  struct gve_index_list *list,
+				  struct gve_rx_buf_state_dqo *buf_state)
+{
+	s16 buffer_id = buf_state - rx->dqo.buf_states;
+
+	buf_state->next = -1;
+
+	if (list->head == -1) {
+		list->head = buffer_id;
+		list->tail = buffer_id;
+	} else {
+		int tail = list->tail;
+
+		rx->dqo.buf_states[tail].next = buffer_id;
+		list->tail = buffer_id;
+	}
+}
+
+static struct gve_rx_buf_state_dqo *
+gve_get_recycled_buf_state(struct gve_rx_ring *rx)
+{
+	struct gve_rx_buf_state_dqo *buf_state;
+	int i;
+
+	/* Recycled buf states are immediately usable. */
+	buf_state = gve_dequeue_buf_state(rx, &rx->dqo.recycled_buf_states);
+	if (likely(buf_state))
+		return buf_state;
+
+	if (unlikely(rx->dqo.used_buf_states.head == -1))
+		return NULL;
+
+	/* Used buf states are only usable when ref count reaches 0, which means
+	 * no SKBs refer to them.
+	 *
+	 * Search a limited number before giving up.
+	 */
+	for (i = 0; i < 5; i++) {
+		buf_state = gve_dequeue_buf_state(rx, &rx->dqo.used_buf_states);
+		if (gve_buf_ref_cnt(buf_state) == 0)
+			return buf_state;
+
+		gve_enqueue_buf_state(rx, &rx->dqo.used_buf_states, buf_state);
+	}
+
+	/* If there are no free buf states discard an entry from
+	 * `used_buf_states` so it can be used.
+	 */
+	if (unlikely(rx->dqo.free_buf_states == -1)) {
+		buf_state = gve_dequeue_buf_state(rx, &rx->dqo.used_buf_states);
+		if (gve_buf_ref_cnt(buf_state) == 0)
+			return buf_state;
+
+		gve_free_page_dqo(rx->gve, buf_state);
+		gve_free_buf_state(rx, buf_state);
+	}
+
+	return NULL;
+}
+
+static int gve_alloc_page_dqo(struct gve_priv *priv,
+			      struct gve_rx_buf_state_dqo *buf_state)
+{
+	int err;
+
+	err = gve_alloc_page(priv, &priv->pdev->dev, &buf_state->page_info.page,
+			     &buf_state->addr, DMA_FROM_DEVICE);
+	if (err)
+		return err;
+
+	buf_state->page_info.page_offset = 0;
+	buf_state->page_info.page_address =
+		page_address(buf_state->page_info.page);
+	buf_state->last_single_ref_offset = 0;
+
+	/* The page already has 1 ref. */
+	page_ref_add(buf_state->page_info.page, INT_MAX - 1);
+	buf_state->page_info.pagecnt_bias = INT_MAX;
+
+	return 0;
+}
+
+static void gve_rx_free_ring_dqo(struct gve_priv *priv, int idx)
+{
+	struct gve_rx_ring *rx = &priv->rx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	size_t completion_queue_slots;
+	size_t buffer_queue_slots;
+	size_t size;
+	int i;
+
+	completion_queue_slots = rx->dqo.complq.mask + 1;
+	buffer_queue_slots = rx->dqo.bufq.mask + 1;
+
+	gve_rx_remove_from_block(priv, idx);
+
+	if (rx->q_resources) {
+		dma_free_coherent(hdev, sizeof(*rx->q_resources),
+				  rx->q_resources, rx->q_resources_bus);
+		rx->q_resources = NULL;
+	}
+
+	for (i = 0; i < rx->dqo.num_buf_states; i++) {
+		struct gve_rx_buf_state_dqo *bs = &rx->dqo.buf_states[i];
+
+		if (bs->page_info.page)
+			gve_free_page_dqo(priv, bs);
+	}
+
+	if (rx->dqo.bufq.desc_ring) {
+		size = sizeof(rx->dqo.bufq.desc_ring[0]) * buffer_queue_slots;
+		dma_free_coherent(hdev, size, rx->dqo.bufq.desc_ring,
+				  rx->dqo.bufq.bus);
+		rx->dqo.bufq.desc_ring = NULL;
+	}
+
+	if (rx->dqo.complq.desc_ring) {
+		size = sizeof(rx->dqo.complq.desc_ring[0]) *
+			completion_queue_slots;
+		dma_free_coherent(hdev, size, rx->dqo.complq.desc_ring,
+				  rx->dqo.complq.bus);
+		rx->dqo.complq.desc_ring = NULL;
+	}
+
+	kvfree(rx->dqo.buf_states);
+	rx->dqo.buf_states = NULL;
+
+	netif_dbg(priv, drv, priv->dev, "freed rx ring %d\n", idx);
+}
+
+static int gve_rx_alloc_ring_dqo(struct gve_priv *priv, int idx)
+{
+	struct gve_rx_ring *rx = &priv->rx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	size_t size;
+	int i;
+
+	const u32 buffer_queue_slots =
+		priv->options_dqo_rda.rx_buff_ring_entries;
+	const u32 completion_queue_slots = priv->rx_desc_cnt;
+
+	netif_dbg(priv, drv, priv->dev, "allocating rx ring DQO\n");
+
+	memset(rx, 0, sizeof(*rx));
+	rx->gve = priv;
+	rx->q_num = idx;
+	rx->dqo.bufq.mask = buffer_queue_slots - 1;
+	rx->dqo.complq.num_free_slots = completion_queue_slots;
+	rx->dqo.complq.mask = completion_queue_slots - 1;
+	rx->skb_head = NULL;
+	rx->skb_tail = NULL;
+
+	rx->dqo.num_buf_states = min_t(s16, S16_MAX, buffer_queue_slots * 4);
+	rx->dqo.buf_states = kvcalloc(rx->dqo.num_buf_states,
+				      sizeof(rx->dqo.buf_states[0]),
+				      GFP_KERNEL);
+	if (!rx->dqo.buf_states)
+		return -ENOMEM;
+
+	/* Set up linked list of buffer IDs */
+	for (i = 0; i < rx->dqo.num_buf_states - 1; i++)
+		rx->dqo.buf_states[i].next = i + 1;
+
+	rx->dqo.buf_states[rx->dqo.num_buf_states - 1].next = -1;
+	rx->dqo.recycled_buf_states.head = -1;
+	rx->dqo.recycled_buf_states.tail = -1;
+	rx->dqo.used_buf_states.head = -1;
+	rx->dqo.used_buf_states.tail = -1;
+
+	/* Allocate RX completion queue */
+	size = sizeof(rx->dqo.complq.desc_ring[0]) *
+		completion_queue_slots;
+	rx->dqo.complq.desc_ring =
+		dma_alloc_coherent(hdev, size, &rx->dqo.complq.bus, GFP_KERNEL);
+	if (!rx->dqo.complq.desc_ring)
+		goto err;
+
+	/* Allocate RX buffer queue */
+	size = sizeof(rx->dqo.bufq.desc_ring[0]) * buffer_queue_slots;
+	rx->dqo.bufq.desc_ring =
+		dma_alloc_coherent(hdev, size, &rx->dqo.bufq.bus, GFP_KERNEL);
+	if (!rx->dqo.bufq.desc_ring)
+		goto err;
+
+	rx->q_resources = dma_alloc_coherent(hdev, sizeof(*rx->q_resources),
+					     &rx->q_resources_bus, GFP_KERNEL);
+	if (!rx->q_resources)
+		goto err;
+
+	gve_rx_add_to_block(priv, idx);
+
+	return 0;
+
+err:
+	gve_rx_free_ring_dqo(priv, idx);
+	return -ENOMEM;
+}
+
+void gve_rx_write_doorbell_dqo(const struct gve_priv *priv, int queue_idx)
+{
+	const struct gve_rx_ring *rx = &priv->rx[queue_idx];
+	u64 index = be32_to_cpu(rx->q_resources->db_index);
+
+	iowrite32(rx->dqo.bufq.tail, &priv->db_bar2[index]);
+}
+
+int gve_rx_alloc_rings_dqo(struct gve_priv *priv)
+{
+	int err = 0;
+	int i;
+
+	for (i = 0; i < priv->rx_cfg.num_queues; i++) {
+		err = gve_rx_alloc_ring_dqo(priv, i);
+		if (err) {
+			netif_err(priv, drv, priv->dev,
+				  "Failed to alloc rx ring=%d: err=%d\n",
+				  i, err);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	for (i--; i >= 0; i--)
+		gve_rx_free_ring_dqo(priv, i);
+
+	return err;
+}
+
+void gve_rx_free_rings_dqo(struct gve_priv *priv)
+{
+	int i;
+
+	for (i = 0; i < priv->rx_cfg.num_queues; i++)
+		gve_rx_free_ring_dqo(priv, i);
+}
+
+void gve_rx_post_buffers_dqo(struct gve_rx_ring *rx)
+{
+	struct gve_rx_compl_queue_dqo *complq = &rx->dqo.complq;
+	struct gve_rx_buf_queue_dqo *bufq = &rx->dqo.bufq;
+	struct gve_priv *priv = rx->gve;
+	u32 num_avail_slots;
+	u32 num_full_slots;
+	u32 num_posted = 0;
+
+	num_full_slots = (bufq->tail - bufq->head) & bufq->mask;
+	num_avail_slots = bufq->mask - num_full_slots;
+
+	num_avail_slots = min_t(u32, num_avail_slots, complq->num_free_slots);
+	while (num_posted < num_avail_slots) {
+		struct gve_rx_desc_dqo *desc = &bufq->desc_ring[bufq->tail];
+		struct gve_rx_buf_state_dqo *buf_state;
+
+		buf_state = gve_get_recycled_buf_state(rx);
+		if (unlikely(!buf_state)) {
+			buf_state = gve_alloc_buf_state(rx);
+			if (unlikely(!buf_state))
+				break;
+
+			if (unlikely(gve_alloc_page_dqo(priv, buf_state))) {
+				u64_stats_update_begin(&rx->statss);
+				rx->rx_buf_alloc_fail++;
+				u64_stats_update_end(&rx->statss);
+				gve_free_buf_state(rx, buf_state);
+				break;
+			}
+		}
+
+		desc->buf_id = cpu_to_le16(buf_state - rx->dqo.buf_states);
+		desc->buf_addr = cpu_to_le64(buf_state->addr +
+					     buf_state->page_info.page_offset);
+
+		bufq->tail = (bufq->tail + 1) & bufq->mask;
+		complq->num_free_slots--;
+		num_posted++;
+
+		if ((bufq->tail & (GVE_RX_BUF_THRESH_DQO - 1)) == 0)
+			gve_rx_write_doorbell_dqo(priv, rx->q_num);
+	}
+
+	rx->fill_cnt += num_posted;
+}
+
+static void gve_try_recycle_buf(struct gve_priv *priv, struct gve_rx_ring *rx,
+				struct gve_rx_buf_state_dqo *buf_state)
+{
+	const int data_buffer_size = priv->data_buffer_size_dqo;
+	int pagecount;
+
+	/* Can't reuse if we only fit one buffer per page */
+	if (data_buffer_size * 2 > PAGE_SIZE)
+		goto mark_used;
+
+	pagecount = gve_buf_ref_cnt(buf_state);
+
+	/* Record the offset when we have a single remaining reference.
+	 *
+	 * When this happens, we know all of the other offsets of the page are
+	 * usable.
+	 */
+	if (pagecount == 1) {
+		buf_state->last_single_ref_offset =
+			buf_state->page_info.page_offset;
+	}
+
+	/* Use the next buffer sized chunk in the page. */
+	buf_state->page_info.page_offset += data_buffer_size;
+	buf_state->page_info.page_offset &= (PAGE_SIZE - 1);
+
+	/* If we wrap around to the same offset without ever dropping to 1
+	 * reference, then we don't know if this offset was ever freed.
+	 */
+	if (buf_state->page_info.page_offset ==
+	    buf_state->last_single_ref_offset) {
+		goto mark_used;
+	}
+
+	gve_enqueue_buf_state(rx, &rx->dqo.recycled_buf_states, buf_state);
+	return;
+
+mark_used:
+	gve_enqueue_buf_state(rx, &rx->dqo.used_buf_states, buf_state);
+}
+
+static void gve_rx_skb_csum(struct sk_buff *skb,
+			    const struct gve_rx_compl_desc_dqo *desc,
+			    struct gve_ptype ptype)
+{
+	skb->ip_summed = CHECKSUM_NONE;
+
+	/* HW did not identify and process L3 and L4 headers. */
+	if (unlikely(!desc->l3_l4_processed))
+		return;
+
+	if (ptype.l3_type == GVE_L3_TYPE_IPV4) {
+		if (unlikely(desc->csum_ip_err || desc->csum_external_ip_err))
+			return;
+	} else if (ptype.l3_type == GVE_L3_TYPE_IPV6) {
+		/* Checksum should be skipped if this flag is set. */
+		if (unlikely(desc->ipv6_ex_add))
+			return;
+	}
+
+	if (unlikely(desc->csum_l4_err))
+		return;
+
+	switch (ptype.l4_type) {
+	case GVE_L4_TYPE_TCP:
+	case GVE_L4_TYPE_UDP:
+	case GVE_L4_TYPE_ICMP:
+	case GVE_L4_TYPE_SCTP:
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+		break;
+	default:
+		break;
+	}
+}
+
+static void gve_rx_skb_hash(struct sk_buff *skb,
+			    const struct gve_rx_compl_desc_dqo *compl_desc,
+			    struct gve_ptype ptype)
+{
+	enum pkt_hash_types hash_type = PKT_HASH_TYPE_L2;
+
+	if (ptype.l4_type != GVE_L4_TYPE_UNKNOWN)
+		hash_type = PKT_HASH_TYPE_L4;
+	else if (ptype.l3_type != GVE_L3_TYPE_UNKNOWN)
+		hash_type = PKT_HASH_TYPE_L3;
+
+	skb_set_hash(skb, le32_to_cpu(compl_desc->hash), hash_type);
+}
+
+static void gve_rx_free_skb(struct gve_rx_ring *rx)
+{
+	if (!rx->skb_head)
+		return;
+
+	dev_kfree_skb_any(rx->skb_head);
+	rx->skb_head = NULL;
+	rx->skb_tail = NULL;
+}
+
+/* Chains multi skbs for single rx packet.
+ * Returns 0 if buffer is appended, -1 otherwise.
+ */
+static int gve_rx_append_frags(struct napi_struct *napi,
+			       struct gve_rx_buf_state_dqo *buf_state,
+			       u16 buf_len, struct gve_rx_ring *rx,
+			       struct gve_priv *priv)
+{
+	int num_frags = skb_shinfo(rx->skb_tail)->nr_frags;
+
+	if (unlikely(num_frags == MAX_SKB_FRAGS)) {
+		struct sk_buff *skb;
+
+		skb = napi_alloc_skb(napi, 0);
+		if (!skb)
+			return -1;
+
+		skb_shinfo(rx->skb_tail)->frag_list = skb;
+		rx->skb_tail = skb;
+		num_frags = 0;
+	}
+	if (rx->skb_tail != rx->skb_head) {
+		rx->skb_head->len += buf_len;
+		rx->skb_head->data_len += buf_len;
+		rx->skb_head->truesize += priv->data_buffer_size_dqo;
+	}
+
+	skb_add_rx_frag(rx->skb_tail, num_frags,
+			buf_state->page_info.page,
+			buf_state->page_info.page_offset,
+			buf_len, priv->data_buffer_size_dqo);
+	gve_dec_pagecnt_bias(&buf_state->page_info);
+
+	return 0;
+}
+
+/* Returns 0 if descriptor is completed successfully.
+ * Returns -EINVAL if descriptor is invalid.
+ * Returns -ENOMEM if data cannot be copied to skb.
+ */
+static int gve_rx_dqo(struct napi_struct *napi, struct gve_rx_ring *rx,
+		      const struct gve_rx_compl_desc_dqo *compl_desc,
+		      int queue_idx)
+{
+	const u16 buffer_id = le16_to_cpu(compl_desc->buf_id);
+	const bool eop = compl_desc->end_of_packet != 0;
+	struct gve_rx_buf_state_dqo *buf_state;
+	struct gve_priv *priv = rx->gve;
+	u16 buf_len;
+
+	if (unlikely(buffer_id > rx->dqo.num_buf_states)) {
+		net_err_ratelimited("%s: Invalid RX buffer_id=%u\n",
+				    priv->dev->name, buffer_id);
+		return -EINVAL;
+	}
+	buf_state = &rx->dqo.buf_states[buffer_id];
+	if (unlikely(!gve_buf_state_is_allocated(rx, buf_state))) {
+		net_err_ratelimited("%s: RX buffer_id is not allocated: %u\n",
+				    priv->dev->name, buffer_id);
+		return -EINVAL;
+	}
+
+	if (unlikely(compl_desc->rx_error)) {
+		gve_enqueue_buf_state(rx, &rx->dqo.recycled_buf_states,
+				      buf_state);
+		return -EINVAL;
+	}
+
+	buf_len = compl_desc->packet_len;
+
+	/* Page might have not been used for awhile and was likely last written
+	 * by a different thread.
+	 */
+	prefetch(buf_state->page_info.page);
+
+	/* Sync the portion of dma buffer for CPU to read. */
+	dma_sync_single_range_for_cpu(&priv->pdev->dev, buf_state->addr,
+				      buf_state->page_info.page_offset,
+				      buf_len, DMA_FROM_DEVICE);
+
+	/* Append to current skb if one exists. */
+	if (rx->skb_head) {
+		if (unlikely(gve_rx_append_frags(napi, buf_state, buf_len, rx,
+						 priv)) != 0) {
+			goto error;
+		}
+
+		gve_try_recycle_buf(priv, rx, buf_state);
+		return 0;
+	}
+
+	/* Prefetch the payload header. */
+	prefetch((char *)buf_state->addr + buf_state->page_info.page_offset);
+#if L1_CACHE_BYTES < 128
+	prefetch((char *)buf_state->addr + buf_state->page_info.page_offset +
+		 L1_CACHE_BYTES);
+#endif
+
+	if (eop && buf_len <= priv->rx_copybreak) {
+		rx->skb_head = gve_rx_copy(priv->dev, napi,
+					   &buf_state->page_info, buf_len, 0);
+		if (unlikely(!rx->skb_head))
+			goto error;
+		rx->skb_tail = rx->skb_head;
+
+		u64_stats_update_begin(&rx->statss);
+		rx->rx_copied_pkt++;
+		rx->rx_copybreak_pkt++;
+		u64_stats_update_end(&rx->statss);
+
+		gve_enqueue_buf_state(rx, &rx->dqo.recycled_buf_states,
+				      buf_state);
+		return 0;
+	}
+
+	rx->skb_head = napi_get_frags(napi);
+	if (unlikely(!rx->skb_head))
+		goto error;
+	rx->skb_tail = rx->skb_head;
+
+	skb_add_rx_frag(rx->skb_head, 0, buf_state->page_info.page,
+			buf_state->page_info.page_offset, buf_len,
+			priv->data_buffer_size_dqo);
+	gve_dec_pagecnt_bias(&buf_state->page_info);
+
+	gve_try_recycle_buf(priv, rx, buf_state);
+	return 0;
+
+error:
+	gve_enqueue_buf_state(rx, &rx->dqo.recycled_buf_states, buf_state);
+	return -ENOMEM;
+}
+
+static int gve_rx_complete_rsc(struct sk_buff *skb,
+			       const struct gve_rx_compl_desc_dqo *desc,
+			       struct gve_ptype ptype)
+{
+	struct skb_shared_info *shinfo = skb_shinfo(skb);
+
+	/* Only TCP is supported right now. */
+	if (ptype.l4_type != GVE_L4_TYPE_TCP)
+		return -EINVAL;
+
+	switch (ptype.l3_type) {
+	case GVE_L3_TYPE_IPV4:
+		shinfo->gso_type = SKB_GSO_TCPV4;
+		break;
+	case GVE_L3_TYPE_IPV6:
+		shinfo->gso_type = SKB_GSO_TCPV6;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	shinfo->gso_size = le16_to_cpu(desc->rsc_seg_len);
+	return 0;
+}
+
+/* Returns 0 if skb is completed successfully, -1 otherwise. */
+static int gve_rx_complete_skb(struct gve_rx_ring *rx, struct napi_struct *napi,
+			       const struct gve_rx_compl_desc_dqo *desc,
+			       netdev_features_t feat)
+{
+	struct gve_ptype ptype =
+		rx->gve->ptype_lut_dqo->ptypes[desc->packet_type];
+	int err;
+
+	skb_record_rx_queue(rx->skb_head, rx->q_num);
+
+	if (feat & NETIF_F_RXHASH)
+		gve_rx_skb_hash(rx->skb_head, desc, ptype);
+
+	if (feat & NETIF_F_RXCSUM)
+		gve_rx_skb_csum(rx->skb_head, desc, ptype);
+
+	/* RSC packets must set gso_size otherwise the TCP stack will complain
+	 * that packets are larger than MTU.
+	 */
+	if (desc->rsc) {
+		err = gve_rx_complete_rsc(rx->skb_head, desc, ptype);
+		if (err < 0)
+			return err;
+	}
+
+	if (skb_headlen(rx->skb_head) == 0)
+		napi_gro_frags(napi);
+	else
+		napi_gro_receive(napi, rx->skb_head);
+
+	return 0;
+}
+
+int gve_rx_poll_dqo(struct gve_notify_block *block, int budget)
+{
+	struct napi_struct *napi = &block->napi;
+	netdev_features_t feat = napi->dev->features;
+
+	struct gve_rx_ring *rx = block->rx;
+	struct gve_rx_compl_queue_dqo *complq = &rx->dqo.complq;
+
+	u32 work_done = 0;
+	u64 bytes = 0;
+	int err;
+
+	while (work_done < budget) {
+		struct gve_rx_compl_desc_dqo *compl_desc =
+			&complq->desc_ring[complq->head];
+		u32 pkt_bytes;
+
+		/* No more new packets */
+		if (compl_desc->generation == complq->cur_gen_bit)
+			break;
+
+		/* Prefetch the next two descriptors. */
+		prefetch(&complq->desc_ring[(complq->head + 1) & complq->mask]);
+		prefetch(&complq->desc_ring[(complq->head + 2) & complq->mask]);
+
+		/* Do not read data until we own the descriptor */
+		dma_rmb();
+
+		err = gve_rx_dqo(napi, rx, compl_desc, rx->q_num);
+		if (err < 0) {
+			gve_rx_free_skb(rx);
+			u64_stats_update_begin(&rx->statss);
+			if (err == -ENOMEM)
+				rx->rx_skb_alloc_fail++;
+			else if (err == -EINVAL)
+				rx->rx_desc_err_dropped_pkt++;
+			u64_stats_update_end(&rx->statss);
+		}
+
+		complq->head = (complq->head + 1) & complq->mask;
+		complq->num_free_slots++;
+
+		/* When the ring wraps, the generation bit is flipped. */
+		complq->cur_gen_bit ^= (complq->head == 0);
+
+		/* Receiving a completion means we have space to post another
+		 * buffer on the buffer queue.
+		 */
+		{
+			struct gve_rx_buf_queue_dqo *bufq = &rx->dqo.bufq;
+
+			bufq->head = (bufq->head + 1) & bufq->mask;
+		}
+
+		/* Free running counter of completed descriptors */
+		rx->cnt++;
+
+		if (!rx->skb_head)
+			continue;
+
+		if (!compl_desc->end_of_packet)
+			continue;
+
+		work_done++;
+		pkt_bytes = rx->skb_head->len;
+		/* The ethernet header (first ETH_HLEN bytes) is snipped off
+		 * by eth_type_trans.
+		 */
+		if (skb_headlen(rx->skb_head))
+			pkt_bytes += ETH_HLEN;
+
+		/* gve_rx_complete_skb() will consume skb if successful */
+		if (gve_rx_complete_skb(rx, napi, compl_desc, feat) != 0) {
+			gve_rx_free_skb(rx);
+			u64_stats_update_begin(&rx->statss);
+			rx->rx_desc_err_dropped_pkt++;
+			u64_stats_update_end(&rx->statss);
+			continue;
+		}
+
+		bytes += pkt_bytes;
+		rx->skb_head = NULL;
+		rx->skb_tail = NULL;
+	}
+
+	gve_rx_post_buffers_dqo(rx);
+
+	u64_stats_update_begin(&rx->statss);
+	rx->rpackets += work_done;
+	rx->rbytes += bytes;
+	u64_stats_update_end(&rx->statss);
+
+	return work_done;
+}

drivers/net/ethernet/google/gve/gve_tx.c

 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
 /* Google virtual Ethernet (gve) driver
  *
- * Copyright (C) 2015-2019 Google, Inc.
+ * Copyright (C) 2015-2021 Google, Inc.
  */
 
 #include "gve.h"
 #include "gve_adminq.h"
+#include "gve_utils.h"
 #include <linux/ip.h>
 #include <linux/tcp.h>
 #include <linux/vmalloc.h>
@@ -131,14 +132,6 @@ static void gve_tx_free_fifo(struct gve_tx_fifo *fifo, size_t bytes)
 	atomic_add(bytes, &fifo->available);
 }
 
-static void gve_tx_remove_from_block(struct gve_priv *priv, int queue_idx)
-{
-	struct gve_notify_block *block =
-			&priv->ntfy_blocks[gve_tx_idx_to_ntfy(priv, queue_idx)];
-
-	block->tx = NULL;
-}
-
 static int gve_clean_tx_done(struct gve_priv *priv, struct gve_tx_ring *tx,
 			     u32 to_do, bool try_to_wake);
 
@@ -174,16 +167,6 @@ static void gve_tx_free_ring(struct gve_priv *priv, int idx)
 	netif_dbg(priv, drv, priv->dev, "freed tx queue %d\n", idx);
 }
 
-static void gve_tx_add_to_block(struct gve_priv *priv, int queue_idx)
-{
-	int ntfy_idx = gve_tx_idx_to_ntfy(priv, queue_idx);
-	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
-	struct gve_tx_ring *tx = &priv->tx[queue_idx];
-
-	block->tx = tx;
-	tx->ntfy_id = ntfy_idx;
-}
-
 static int gve_tx_alloc_ring(struct gve_priv *priv, int idx)
 {
 	struct gve_tx_ring *tx = &priv->tx[idx];
@@ -208,7 +191,7 @@ static int gve_tx_alloc_ring(struct gve_priv *priv, int idx)
 	if (!tx->desc)
 		goto abort_with_info;
 
-	tx->raw_addressing = priv->raw_addressing;
+	tx->raw_addressing = priv->queue_format == GVE_GQI_RDA_FORMAT;
 	tx->dev = &priv->pdev->dev;
 	if (!tx->raw_addressing) {
 		tx->tx_fifo.qpl = gve_assign_tx_qpl(priv);
@@ -273,7 +256,7 @@ int gve_tx_alloc_rings(struct gve_priv *priv)
 	return err;
 }
 
-void gve_tx_free_rings(struct gve_priv *priv)
+void gve_tx_free_rings_gqi(struct gve_priv *priv)
 {
 	int i;
 

drivers/net/ethernet/google/gve/gve_tx_dqo.c

+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+#include "gve.h"
+#include "gve_adminq.h"
+#include "gve_utils.h"
+#include "gve_dqo.h"
+#include <linux/tcp.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+
+/* Returns true if a gve_tx_pending_packet_dqo object is available. */
+static bool gve_has_pending_packet(struct gve_tx_ring *tx)
+{
+	/* Check TX path's list. */
+	if (tx->dqo_tx.free_pending_packets != -1)
+		return true;
+
+	/* Check completion handler's list. */
+	if (atomic_read_acquire(&tx->dqo_compl.free_pending_packets) != -1)
+		return true;
+
+	return false;
+}
+
+static struct gve_tx_pending_packet_dqo *
+gve_alloc_pending_packet(struct gve_tx_ring *tx)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	s16 index;
+
+	index = tx->dqo_tx.free_pending_packets;
+
+	/* No pending_packets available, try to steal the list from the
+	 * completion handler.
+	 */
+	if (unlikely(index == -1)) {
+		tx->dqo_tx.free_pending_packets =
+			atomic_xchg(&tx->dqo_compl.free_pending_packets, -1);
+		index = tx->dqo_tx.free_pending_packets;
+
+		if (unlikely(index == -1))
+			return NULL;
+	}
+
+	pending_packet = &tx->dqo.pending_packets[index];
+
+	/* Remove pending_packet from free list */
+	tx->dqo_tx.free_pending_packets = pending_packet->next;
+	pending_packet->state = GVE_PACKET_STATE_PENDING_DATA_COMPL;
+
+	return pending_packet;
+}
+
+static void
+gve_free_pending_packet(struct gve_tx_ring *tx,
+			struct gve_tx_pending_packet_dqo *pending_packet)
+{
+	s16 index = pending_packet - tx->dqo.pending_packets;
+
+	pending_packet->state = GVE_PACKET_STATE_UNALLOCATED;
+	while (true) {
+		s16 old_head = atomic_read_acquire(&tx->dqo_compl.free_pending_packets);
+
+		pending_packet->next = old_head;
+		if (atomic_cmpxchg(&tx->dqo_compl.free_pending_packets,
+				   old_head, index) == old_head) {
+			break;
+		}
+	}
+}
+
+/* gve_tx_free_desc - Cleans up all pending tx requests and buffers.
+ */
+static void gve_tx_clean_pending_packets(struct gve_tx_ring *tx)
+{
+	int i;
+
+	for (i = 0; i < tx->dqo.num_pending_packets; i++) {
+		struct gve_tx_pending_packet_dqo *cur_state =
+			&tx->dqo.pending_packets[i];
+		int j;
+
+		for (j = 0; j < cur_state->num_bufs; j++) {
+			struct gve_tx_dma_buf *buf = &cur_state->bufs[j];
+
+			if (j == 0) {
+				dma_unmap_single(tx->dev,
+						 dma_unmap_addr(buf, dma),
+						 dma_unmap_len(buf, len),
+						 DMA_TO_DEVICE);
+			} else {
+				dma_unmap_page(tx->dev,
+					       dma_unmap_addr(buf, dma),
+					       dma_unmap_len(buf, len),
+					       DMA_TO_DEVICE);
+			}
+		}
+		if (cur_state->skb) {
+			dev_consume_skb_any(cur_state->skb);
+			cur_state->skb = NULL;
+		}
+	}
+}
+
+static void gve_tx_free_ring_dqo(struct gve_priv *priv, int idx)
+{
+	struct gve_tx_ring *tx = &priv->tx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	size_t bytes;
+
+	gve_tx_remove_from_block(priv, idx);
+
+	if (tx->q_resources) {
+		dma_free_coherent(hdev, sizeof(*tx->q_resources),
+				  tx->q_resources, tx->q_resources_bus);
+		tx->q_resources = NULL;
+	}
+
+	if (tx->dqo.compl_ring) {
+		bytes = sizeof(tx->dqo.compl_ring[0]) *
+			(tx->dqo.complq_mask + 1);
+		dma_free_coherent(hdev, bytes, tx->dqo.compl_ring,
+				  tx->complq_bus_dqo);
+		tx->dqo.compl_ring = NULL;
+	}
+
+	if (tx->dqo.tx_ring) {
+		bytes = sizeof(tx->dqo.tx_ring[0]) * (tx->mask + 1);
+		dma_free_coherent(hdev, bytes, tx->dqo.tx_ring, tx->bus);
+		tx->dqo.tx_ring = NULL;
+	}
+
+	kvfree(tx->dqo.pending_packets);
+	tx->dqo.pending_packets = NULL;
+
+	netif_dbg(priv, drv, priv->dev, "freed tx queue %d\n", idx);
+}
+
+static int gve_tx_alloc_ring_dqo(struct gve_priv *priv, int idx)
+{
+	struct gve_tx_ring *tx = &priv->tx[idx];
+	struct device *hdev = &priv->pdev->dev;
+	int num_pending_packets;
+	size_t bytes;
+	int i;
+
+	memset(tx, 0, sizeof(*tx));
+	tx->q_num = idx;
+	tx->dev = &priv->pdev->dev;
+	tx->netdev_txq = netdev_get_tx_queue(priv->dev, idx);
+	atomic_set_release(&tx->dqo_compl.hw_tx_head, 0);
+
+	/* Queue sizes must be a power of 2 */
+	tx->mask = priv->tx_desc_cnt - 1;
+	tx->dqo.complq_mask = priv->options_dqo_rda.tx_comp_ring_entries - 1;
+
+	/* The max number of pending packets determines the maximum number of
+	 * descriptors which maybe written to the completion queue.
+	 *
+	 * We must set the number small enough to make sure we never overrun the
+	 * completion queue.
+	 */
+	num_pending_packets = tx->dqo.complq_mask + 1;
+
+	/* Reserve space for descriptor completions, which will be reported at
+	 * most every GVE_TX_MIN_RE_INTERVAL packets.
+	 */
+	num_pending_packets -=
+		(tx->dqo.complq_mask + 1) / GVE_TX_MIN_RE_INTERVAL;
+
+	/* Each packet may have at most 2 buffer completions if it receives both
+	 * a miss and reinjection completion.
+	 */
+	num_pending_packets /= 2;
+
+	tx->dqo.num_pending_packets = min_t(int, num_pending_packets, S16_MAX);
+	tx->dqo.pending_packets = kvcalloc(tx->dqo.num_pending_packets,
+					   sizeof(tx->dqo.pending_packets[0]),
+					   GFP_KERNEL);
+	if (!tx->dqo.pending_packets)
+		goto err;
+
+	/* Set up linked list of pending packets */
+	for (i = 0; i < tx->dqo.num_pending_packets - 1; i++)
+		tx->dqo.pending_packets[i].next = i + 1;
+
+	tx->dqo.pending_packets[tx->dqo.num_pending_packets - 1].next = -1;
+	atomic_set_release(&tx->dqo_compl.free_pending_packets, -1);
+	tx->dqo_compl.miss_completions.head = -1;
+	tx->dqo_compl.miss_completions.tail = -1;
+	tx->dqo_compl.timed_out_completions.head = -1;
+	tx->dqo_compl.timed_out_completions.tail = -1;
+
+	bytes = sizeof(tx->dqo.tx_ring[0]) * (tx->mask + 1);
+	tx->dqo.tx_ring = dma_alloc_coherent(hdev, bytes, &tx->bus, GFP_KERNEL);
+	if (!tx->dqo.tx_ring)
+		goto err;
+
+	bytes = sizeof(tx->dqo.compl_ring[0]) * (tx->dqo.complq_mask + 1);
+	tx->dqo.compl_ring = dma_alloc_coherent(hdev, bytes,
+						&tx->complq_bus_dqo,
+						GFP_KERNEL);
+	if (!tx->dqo.compl_ring)
+		goto err;
+
+	tx->q_resources = dma_alloc_coherent(hdev, sizeof(*tx->q_resources),
+					     &tx->q_resources_bus, GFP_KERNEL);
+	if (!tx->q_resources)
+		goto err;
+
+	gve_tx_add_to_block(priv, idx);
+
+	return 0;
+
+err:
+	gve_tx_free_ring_dqo(priv, idx);
+	return -ENOMEM;
+}
+
+int gve_tx_alloc_rings_dqo(struct gve_priv *priv)
+{
+	int err = 0;
+	int i;
+
+	for (i = 0; i < priv->tx_cfg.num_queues; i++) {
+		err = gve_tx_alloc_ring_dqo(priv, i);
+		if (err) {
+			netif_err(priv, drv, priv->dev,
+				  "Failed to alloc tx ring=%d: err=%d\n",
+				  i, err);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	for (i--; i >= 0; i--)
+		gve_tx_free_ring_dqo(priv, i);
+
+	return err;
+}
+
+void gve_tx_free_rings_dqo(struct gve_priv *priv)
+{
+	int i;
+
+	for (i = 0; i < priv->tx_cfg.num_queues; i++) {
+		struct gve_tx_ring *tx = &priv->tx[i];
+
+		gve_clean_tx_done_dqo(priv, tx, /*napi=*/NULL);
+		netdev_tx_reset_queue(tx->netdev_txq);
+		gve_tx_clean_pending_packets(tx);
+
+		gve_tx_free_ring_dqo(priv, i);
+	}
+}
+
+/* Returns the number of slots available in the ring */
+static inline u32 num_avail_tx_slots(const struct gve_tx_ring *tx)
+{
+	u32 num_used = (tx->dqo_tx.tail - tx->dqo_tx.head) & tx->mask;
+
+	return tx->mask - num_used;
+}
+
+/* Stops the queue if available descriptors is less than 'count'.
+ * Return: 0 if stop is not required.
+ */
+static int gve_maybe_stop_tx_dqo(struct gve_tx_ring *tx, int count)
+{
+	if (likely(gve_has_pending_packet(tx) &&
+		   num_avail_tx_slots(tx) >= count))
+		return 0;
+
+	/* Update cached TX head pointer */
+	tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
+
+	if (likely(gve_has_pending_packet(tx) &&
+		   num_avail_tx_slots(tx) >= count))
+		return 0;
+
+	/* No space, so stop the queue */
+	tx->stop_queue++;
+	netif_tx_stop_queue(tx->netdev_txq);
+
+	/* Sync with restarting queue in `gve_tx_poll_dqo()` */
+	mb();
+
+	/* After stopping queue, check if we can transmit again in order to
+	 * avoid TOCTOU bug.
+	 */
+	tx->dqo_tx.head = atomic_read_acquire(&tx->dqo_compl.hw_tx_head);
+
+	if (likely(!gve_has_pending_packet(tx) ||
+		   num_avail_tx_slots(tx) < count))
+		return -EBUSY;
+
+	netif_tx_start_queue(tx->netdev_txq);
+	tx->wake_queue++;
+	return 0;
+}
+
+static void gve_extract_tx_metadata_dqo(const struct sk_buff *skb,
+					struct gve_tx_metadata_dqo *metadata)
+{
+	memset(metadata, 0, sizeof(*metadata));
+	metadata->version = GVE_TX_METADATA_VERSION_DQO;
+
+	if (skb->l4_hash) {
+		u16 path_hash = skb->hash ^ (skb->hash >> 16);
+
+		path_hash &= (1 << 15) - 1;
+		if (unlikely(path_hash == 0))
+			path_hash = ~path_hash;
+
+		metadata->path_hash = path_hash;
+	}
+}
+
+static void gve_tx_fill_pkt_desc_dqo(struct gve_tx_ring *tx, u32 *desc_idx,
+				     struct sk_buff *skb, u32 len, u64 addr,
+				     s16 compl_tag, bool eop, bool is_gso)
+{
+	const bool checksum_offload_en = skb->ip_summed == CHECKSUM_PARTIAL;
+
+	while (len > 0) {
+		struct gve_tx_pkt_desc_dqo *desc =
+			&tx->dqo.tx_ring[*desc_idx].pkt;
+		u32 cur_len = min_t(u32, len, GVE_TX_MAX_BUF_SIZE_DQO);
+		bool cur_eop = eop && cur_len == len;
+
+		*desc = (struct gve_tx_pkt_desc_dqo){
+			.buf_addr = cpu_to_le64(addr),
+			.dtype = GVE_TX_PKT_DESC_DTYPE_DQO,
+			.end_of_packet = cur_eop,
+			.checksum_offload_enable = checksum_offload_en,
+			.compl_tag = cpu_to_le16(compl_tag),
+			.buf_size = cur_len,
+		};
+
+		addr += cur_len;
+		len -= cur_len;
+		*desc_idx = (*desc_idx + 1) & tx->mask;
+	}
+}
+
+/* Validates and prepares `skb` for TSO.
+ *
+ * Returns header length, or < 0 if invalid.
+ */
+static int gve_prep_tso(struct sk_buff *skb)
+{
+	struct tcphdr *tcp;
+	int header_len;
+	u32 paylen;
+	int err;
+
+	/* Note: HW requires MSS (gso_size) to be <= 9728 and the total length
+	 * of the TSO to be <= 262143.
+	 *
+	 * However, we don't validate these because:
+	 * - Hypervisor enforces a limit of 9K MTU
+	 * - Kernel will not produce a TSO larger than 64k
+	 */
+
+	if (unlikely(skb_shinfo(skb)->gso_size < GVE_TX_MIN_TSO_MSS_DQO))
+		return -1;
+
+	/* Needed because we will modify header. */
+	err = skb_cow_head(skb, 0);
+	if (err < 0)
+		return err;
+
+	tcp = tcp_hdr(skb);
+
+	/* Remove payload length from checksum. */
+	paylen = skb->len - skb_transport_offset(skb);
+
+	switch (skb_shinfo(skb)->gso_type) {
+	case SKB_GSO_TCPV4:
+	case SKB_GSO_TCPV6:
+		csum_replace_by_diff(&tcp->check,
+				     (__force __wsum)htonl(paylen));
+
+		/* Compute length of segmentation header. */
+		header_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (unlikely(header_len > GVE_TX_MAX_HDR_SIZE_DQO))
+		return -EINVAL;
+
+	return header_len;
+}
+
+static void gve_tx_fill_tso_ctx_desc(struct gve_tx_tso_context_desc_dqo *desc,
+				     const struct sk_buff *skb,
+				     const struct gve_tx_metadata_dqo *metadata,
+				     int header_len)
+{
+	*desc = (struct gve_tx_tso_context_desc_dqo){
+		.header_len = header_len,
+		.cmd_dtype = {
+			.dtype = GVE_TX_TSO_CTX_DESC_DTYPE_DQO,
+			.tso = 1,
+		},
+		.flex0 = metadata->bytes[0],
+		.flex5 = metadata->bytes[5],
+		.flex6 = metadata->bytes[6],
+		.flex7 = metadata->bytes[7],
+		.flex8 = metadata->bytes[8],
+		.flex9 = metadata->bytes[9],
+		.flex10 = metadata->bytes[10],
+		.flex11 = metadata->bytes[11],
+	};
+	desc->tso_total_len = skb->len - header_len;
+	desc->mss = skb_shinfo(skb)->gso_size;
+}
+
+static void
+gve_tx_fill_general_ctx_desc(struct gve_tx_general_context_desc_dqo *desc,
+			     const struct gve_tx_metadata_dqo *metadata)
+{
+	*desc = (struct gve_tx_general_context_desc_dqo){
+		.flex0 = metadata->bytes[0],
+		.flex1 = metadata->bytes[1],
+		.flex2 = metadata->bytes[2],
+		.flex3 = metadata->bytes[3],
+		.flex4 = metadata->bytes[4],
+		.flex5 = metadata->bytes[5],
+		.flex6 = metadata->bytes[6],
+		.flex7 = metadata->bytes[7],
+		.flex8 = metadata->bytes[8],
+		.flex9 = metadata->bytes[9],
+		.flex10 = metadata->bytes[10],
+		.flex11 = metadata->bytes[11],
+		.cmd_dtype = {.dtype = GVE_TX_GENERAL_CTX_DESC_DTYPE_DQO},
+	};
+}
+
+/* Returns 0 on success, or < 0 on error.
+ *
+ * Before this function is called, the caller must ensure
+ * gve_has_pending_packet(tx) returns true.
+ */
+static int gve_tx_add_skb_no_copy_dqo(struct gve_tx_ring *tx,
+				      struct sk_buff *skb)
+{
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	const bool is_gso = skb_is_gso(skb);
+	u32 desc_idx = tx->dqo_tx.tail;
+
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	struct gve_tx_metadata_dqo metadata;
+	s16 completion_tag;
+	int i;
+
+	pending_packet = gve_alloc_pending_packet(tx);
+	pending_packet->skb = skb;
+	pending_packet->num_bufs = 0;
+	completion_tag = pending_packet - tx->dqo.pending_packets;
+
+	gve_extract_tx_metadata_dqo(skb, &metadata);
+	if (is_gso) {
+		int header_len = gve_prep_tso(skb);
+
+		if (unlikely(header_len < 0))
+			goto err;
+
+		gve_tx_fill_tso_ctx_desc(&tx->dqo.tx_ring[desc_idx].tso_ctx,
+					 skb, &metadata, header_len);
+		desc_idx = (desc_idx + 1) & tx->mask;
+	}
+
+	gve_tx_fill_general_ctx_desc(&tx->dqo.tx_ring[desc_idx].general_ctx,
+				     &metadata);
+	desc_idx = (desc_idx + 1) & tx->mask;
+
+	/* Note: HW requires that the size of a non-TSO packet be within the
+	 * range of [17, 9728].
+	 *
+	 * We don't double check because
+	 * - We limited `netdev->min_mtu` to ETH_MIN_MTU.
+	 * - Hypervisor won't allow MTU larger than 9216.
+	 */
+
+	/* Map the linear portion of skb */
+	{
+		struct gve_tx_dma_buf *buf =
+			&pending_packet->bufs[pending_packet->num_bufs];
+		u32 len = skb_headlen(skb);
+		dma_addr_t addr;
+
+		addr = dma_map_single(tx->dev, skb->data, len, DMA_TO_DEVICE);
+		if (unlikely(dma_mapping_error(tx->dev, addr)))
+			goto err;
+
+		dma_unmap_len_set(buf, len, len);
+		dma_unmap_addr_set(buf, dma, addr);
+		++pending_packet->num_bufs;
+
+		gve_tx_fill_pkt_desc_dqo(tx, &desc_idx, skb, len, addr,
+					 completion_tag,
+					 /*eop=*/shinfo->nr_frags == 0, is_gso);
+	}
+
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		struct gve_tx_dma_buf *buf =
+			&pending_packet->bufs[pending_packet->num_bufs];
+		const skb_frag_t *frag = &shinfo->frags[i];
+		bool is_eop = i == (shinfo->nr_frags - 1);
+		u32 len = skb_frag_size(frag);
+		dma_addr_t addr;
+
+		addr = skb_frag_dma_map(tx->dev, frag, 0, len, DMA_TO_DEVICE);
+		if (unlikely(dma_mapping_error(tx->dev, addr)))
+			goto err;
+
+		dma_unmap_len_set(buf, len, len);
+		dma_unmap_addr_set(buf, dma, addr);
+		++pending_packet->num_bufs;
+
+		gve_tx_fill_pkt_desc_dqo(tx, &desc_idx, skb, len, addr,
+					 completion_tag, is_eop, is_gso);
+	}
+
+	/* Commit the changes to our state */
+	tx->dqo_tx.tail = desc_idx;
+
+	/* Request a descriptor completion on the last descriptor of the
+	 * packet if we are allowed to by the HW enforced interval.
+	 */
+	{
+		u32 last_desc_idx = (desc_idx - 1) & tx->mask;
+		u32 last_report_event_interval =
+			(last_desc_idx - tx->dqo_tx.last_re_idx) & tx->mask;
+
+		if (unlikely(last_report_event_interval >=
+			     GVE_TX_MIN_RE_INTERVAL)) {
+			tx->dqo.tx_ring[last_desc_idx].pkt.report_event = true;
+			tx->dqo_tx.last_re_idx = last_desc_idx;
+		}
+	}
+
+	return 0;
+
+err:
+	for (i = 0; i < pending_packet->num_bufs; i++) {
+		struct gve_tx_dma_buf *buf = &pending_packet->bufs[i];
+
+		if (i == 0) {
+			dma_unmap_single(tx->dev, dma_unmap_addr(buf, dma),
+					 dma_unmap_len(buf, len),
+					 DMA_TO_DEVICE);
+		} else {
+			dma_unmap_page(tx->dev, dma_unmap_addr(buf, dma),
+				       dma_unmap_len(buf, len), DMA_TO_DEVICE);
+		}
+	}
+
+	pending_packet->skb = NULL;
+	pending_packet->num_bufs = 0;
+	gve_free_pending_packet(tx, pending_packet);
+
+	return -1;
+}
+
+static int gve_num_descs_per_buf(size_t size)
+{
+	return DIV_ROUND_UP(size, GVE_TX_MAX_BUF_SIZE_DQO);
+}
+
+static int gve_num_buffer_descs_needed(const struct sk_buff *skb)
+{
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	int num_descs;
+	int i;
+
+	num_descs = gve_num_descs_per_buf(skb_headlen(skb));
+
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		unsigned int frag_size = skb_frag_size(&shinfo->frags[i]);
+
+		num_descs += gve_num_descs_per_buf(frag_size);
+	}
+
+	return num_descs;
+}
+
+/* Returns true if HW is capable of sending TSO represented by `skb`.
+ *
+ * Each segment must not span more than GVE_TX_MAX_DATA_DESCS buffers.
+ * - The header is counted as one buffer for every single segment.
+ * - A buffer which is split between two segments is counted for both.
+ * - If a buffer contains both header and payload, it is counted as two buffers.
+ */
+static bool gve_can_send_tso(const struct sk_buff *skb)
+{
+	const int header_len = skb_checksum_start_offset(skb) + tcp_hdrlen(skb);
+	const int max_bufs_per_seg = GVE_TX_MAX_DATA_DESCS - 1;
+	const struct skb_shared_info *shinfo = skb_shinfo(skb);
+	const int gso_size = shinfo->gso_size;
+	int cur_seg_num_bufs;
+	int cur_seg_size;
+	int i;
+
+	cur_seg_size = skb_headlen(skb) - header_len;
+	cur_seg_num_bufs = cur_seg_size > 0;
+
+	for (i = 0; i < shinfo->nr_frags; i++) {
+		if (cur_seg_size >= gso_size) {
+			cur_seg_size %= gso_size;
+			cur_seg_num_bufs = cur_seg_size > 0;
+		}
+
+		if (unlikely(++cur_seg_num_bufs > max_bufs_per_seg))
+			return false;
+
+		cur_seg_size += skb_frag_size(&shinfo->frags[i]);
+	}
+
+	return true;
+}
+
+/* Attempt to transmit specified SKB.
+ *
+ * Returns 0 if the SKB was transmitted or dropped.
+ * Returns -1 if there is not currently enough space to transmit the SKB.
+ */
+static int gve_try_tx_skb(struct gve_priv *priv, struct gve_tx_ring *tx,
+			  struct sk_buff *skb)
+{
+	int num_buffer_descs;
+	int total_num_descs;
+
+	if (skb_is_gso(skb)) {
+		/* If TSO doesn't meet HW requirements, attempt to linearize the
+		 * packet.
+		 */
+		if (unlikely(!gve_can_send_tso(skb) &&
+			     skb_linearize(skb) < 0)) {
+			net_err_ratelimited("%s: Failed to transmit TSO packet\n",
+					    priv->dev->name);
+			goto drop;
+		}
+
+		num_buffer_descs = gve_num_buffer_descs_needed(skb);
+	} else {
+		num_buffer_descs = gve_num_buffer_descs_needed(skb);
+
+		if (unlikely(num_buffer_descs > GVE_TX_MAX_DATA_DESCS)) {
+			if (unlikely(skb_linearize(skb) < 0))
+				goto drop;
+
+			num_buffer_descs = 1;
+		}
+	}
+
+	/* Metadata + (optional TSO) + data descriptors. */
+	total_num_descs = 1 + skb_is_gso(skb) + num_buffer_descs;
+	if (unlikely(gve_maybe_stop_tx_dqo(tx, total_num_descs +
+			GVE_TX_MIN_DESC_PREVENT_CACHE_OVERLAP))) {
+		return -1;
+	}
+
+	if (unlikely(gve_tx_add_skb_no_copy_dqo(tx, skb) < 0))
+		goto drop;
+
+	netdev_tx_sent_queue(tx->netdev_txq, skb->len);
+	skb_tx_timestamp(skb);
+	return 0;
+
+drop:
+	tx->dropped_pkt++;
+	dev_kfree_skb_any(skb);
+	return 0;
+}
+
+/* Transmit a given skb and ring the doorbell. */
+netdev_tx_t gve_tx_dqo(struct sk_buff *skb, struct net_device *dev)
+{
+	struct gve_priv *priv = netdev_priv(dev);
+	struct gve_tx_ring *tx;
+
+	tx = &priv->tx[skb_get_queue_mapping(skb)];
+	if (unlikely(gve_try_tx_skb(priv, tx, skb) < 0)) {
+		/* We need to ring the txq doorbell -- we have stopped the Tx
+		 * queue for want of resources, but prior calls to gve_tx()
+		 * may have added descriptors without ringing the doorbell.
+		 */
+		gve_tx_put_doorbell_dqo(priv, tx->q_resources, tx->dqo_tx.tail);
+		return NETDEV_TX_BUSY;
+	}
+
+	if (!netif_xmit_stopped(tx->netdev_txq) && netdev_xmit_more())
+		return NETDEV_TX_OK;
+
+	gve_tx_put_doorbell_dqo(priv, tx->q_resources, tx->dqo_tx.tail);
+	return NETDEV_TX_OK;
+}
+
+static void add_to_list(struct gve_tx_ring *tx, struct gve_index_list *list,
+			struct gve_tx_pending_packet_dqo *pending_packet)
+{
+	s16 old_tail, index;
+
+	index = pending_packet - tx->dqo.pending_packets;
+	old_tail = list->tail;
+	list->tail = index;
+	if (old_tail == -1)
+		list->head = index;
+	else
+		tx->dqo.pending_packets[old_tail].next = index;
+
+	pending_packet->next = -1;
+	pending_packet->prev = old_tail;
+}
+
+static void remove_from_list(struct gve_tx_ring *tx,
+			     struct gve_index_list *list,
+			     struct gve_tx_pending_packet_dqo *pending_packet)
+{
+	s16 index, prev_index, next_index;
+
+	index = pending_packet - tx->dqo.pending_packets;
+	prev_index = pending_packet->prev;
+	next_index = pending_packet->next;
+
+	if (prev_index == -1) {
+		/* Node is head */
+		list->head = next_index;
+	} else {
+		tx->dqo.pending_packets[prev_index].next = next_index;
+	}
+	if (next_index == -1) {
+		/* Node is tail */
+		list->tail = prev_index;
+	} else {
+		tx->dqo.pending_packets[next_index].prev = prev_index;
+	}
+}
+
+static void gve_unmap_packet(struct device *dev,
+			     struct gve_tx_pending_packet_dqo *pending_packet)
+{
+	struct gve_tx_dma_buf *buf;
+	int i;
+
+	/* SKB linear portion is guaranteed to be mapped */
+	buf = &pending_packet->bufs[0];
+	dma_unmap_single(dev, dma_unmap_addr(buf, dma),
+			 dma_unmap_len(buf, len), DMA_TO_DEVICE);
+	for (i = 1; i < pending_packet->num_bufs; i++) {
+		buf = &pending_packet->bufs[i];
+		dma_unmap_page(dev, dma_unmap_addr(buf, dma),
+			       dma_unmap_len(buf, len), DMA_TO_DEVICE);
+	}
+	pending_packet->num_bufs = 0;
+}
+
+/* Completion types and expected behavior:
+ * No Miss compl + Packet compl = Packet completed normally.
+ * Miss compl + Re-inject compl = Packet completed normally.
+ * No Miss compl + Re-inject compl = Skipped i.e. packet not completed.
+ * Miss compl + Packet compl = Skipped i.e. packet not completed.
+ */
+static void gve_handle_packet_completion(struct gve_priv *priv,
+					 struct gve_tx_ring *tx, bool is_napi,
+					 u16 compl_tag, u64 *bytes, u64 *pkts,
+					 bool is_reinjection)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+
+	if (unlikely(compl_tag >= tx->dqo.num_pending_packets)) {
+		net_err_ratelimited("%s: Invalid TX completion tag: %d\n",
+				    priv->dev->name, (int)compl_tag);
+		return;
+	}
+
+	pending_packet = &tx->dqo.pending_packets[compl_tag];
+
+	if (unlikely(is_reinjection)) {
+		if (unlikely(pending_packet->state ==
+			     GVE_PACKET_STATE_TIMED_OUT_COMPL)) {
+			net_err_ratelimited("%s: Re-injection completion: %d received after timeout.\n",
+					    priv->dev->name, (int)compl_tag);
+			/* Packet was already completed as a result of timeout,
+			 * so just remove from list and free pending packet.
+			 */
+			remove_from_list(tx,
+					 &tx->dqo_compl.timed_out_completions,
+					 pending_packet);
+			gve_free_pending_packet(tx, pending_packet);
+			return;
+		}
+		if (unlikely(pending_packet->state !=
+			     GVE_PACKET_STATE_PENDING_REINJECT_COMPL)) {
+			/* No outstanding miss completion but packet allocated
+			 * implies packet receives a re-injection completion
+			 * without a a prior miss completion. Return without
+			 * completing the packet.
+			 */
+			net_err_ratelimited("%s: Re-injection completion received without corresponding miss completion: %d\n",
+					    priv->dev->name, (int)compl_tag);
+			return;
+		}
+		remove_from_list(tx, &tx->dqo_compl.miss_completions,
+				 pending_packet);
+	} else {
+		/* Packet is allocated but not a pending data completion. */
+		if (unlikely(pending_packet->state !=
+			     GVE_PACKET_STATE_PENDING_DATA_COMPL)) {
+			net_err_ratelimited("%s: No pending data completion: %d\n",
+					    priv->dev->name, (int)compl_tag);
+			return;
+		}
+	}
+	gve_unmap_packet(tx->dev, pending_packet);
+
+	*bytes += pending_packet->skb->len;
+	(*pkts)++;
+	napi_consume_skb(pending_packet->skb, is_napi);
+	pending_packet->skb = NULL;
+	gve_free_pending_packet(tx, pending_packet);
+}
+
+static void gve_handle_miss_completion(struct gve_priv *priv,
+				       struct gve_tx_ring *tx, u16 compl_tag,
+				       u64 *bytes, u64 *pkts)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+
+	if (unlikely(compl_tag >= tx->dqo.num_pending_packets)) {
+		net_err_ratelimited("%s: Invalid TX completion tag: %d\n",
+				    priv->dev->name, (int)compl_tag);
+		return;
+	}
+
+	pending_packet = &tx->dqo.pending_packets[compl_tag];
+	if (unlikely(pending_packet->state !=
+				GVE_PACKET_STATE_PENDING_DATA_COMPL)) {
+		net_err_ratelimited("%s: Unexpected packet state: %d for completion tag : %d\n",
+				    priv->dev->name, (int)pending_packet->state,
+				    (int)compl_tag);
+		return;
+	}
+
+	pending_packet->state = GVE_PACKET_STATE_PENDING_REINJECT_COMPL;
+	/* jiffies can wraparound but time comparisons can handle overflows. */
+	pending_packet->timeout_jiffies =
+			jiffies +
+			msecs_to_jiffies(GVE_REINJECT_COMPL_TIMEOUT *
+					 MSEC_PER_SEC);
+	add_to_list(tx, &tx->dqo_compl.miss_completions, pending_packet);
+
+	*bytes += pending_packet->skb->len;
+	(*pkts)++;
+}
+
+static void remove_miss_completions(struct gve_priv *priv,
+				    struct gve_tx_ring *tx)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	s16 next_index;
+
+	next_index = tx->dqo_compl.miss_completions.head;
+	while (next_index != -1) {
+		pending_packet = &tx->dqo.pending_packets[next_index];
+		next_index = pending_packet->next;
+		/* Break early because packets should timeout in order. */
+		if (time_is_after_jiffies(pending_packet->timeout_jiffies))
+			break;
+
+		remove_from_list(tx, &tx->dqo_compl.miss_completions,
+				 pending_packet);
+		/* Unmap buffers and free skb but do not unallocate packet i.e.
+		 * the completion tag is not freed to ensure that the driver
+		 * can take appropriate action if a corresponding valid
+		 * completion is received later.
+		 */
+		gve_unmap_packet(tx->dev, pending_packet);
+		/* This indicates the packet was dropped. */
+		dev_kfree_skb_any(pending_packet->skb);
+		pending_packet->skb = NULL;
+		tx->dropped_pkt++;
+		net_err_ratelimited("%s: No reinjection completion was received for: %ld.\n",
+				    priv->dev->name,
+				    (pending_packet - tx->dqo.pending_packets));
+
+		pending_packet->state = GVE_PACKET_STATE_TIMED_OUT_COMPL;
+		pending_packet->timeout_jiffies =
+				jiffies +
+				msecs_to_jiffies(GVE_DEALLOCATE_COMPL_TIMEOUT *
+						 MSEC_PER_SEC);
+		/* Maintain pending packet in another list so the packet can be
+		 * unallocated at a later time.
+		 */
+		add_to_list(tx, &tx->dqo_compl.timed_out_completions,
+			    pending_packet);
+	}
+}
+
+static void remove_timed_out_completions(struct gve_priv *priv,
+					 struct gve_tx_ring *tx)
+{
+	struct gve_tx_pending_packet_dqo *pending_packet;
+	s16 next_index;
+
+	next_index = tx->dqo_compl.timed_out_completions.head;
+	while (next_index != -1) {
+		pending_packet = &tx->dqo.pending_packets[next_index];
+		next_index = pending_packet->next;
+		/* Break early because packets should timeout in order. */
+		if (time_is_after_jiffies(pending_packet->timeout_jiffies))
+			break;
+
+		remove_from_list(tx, &tx->dqo_compl.timed_out_completions,
+				 pending_packet);
+		gve_free_pending_packet(tx, pending_packet);
+	}
+}
+
+int gve_clean_tx_done_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
+			  struct napi_struct *napi)
+{
+	u64 reinject_compl_bytes = 0;
+	u64 reinject_compl_pkts = 0;
+	int num_descs_cleaned = 0;
+	u64 miss_compl_bytes = 0;
+	u64 miss_compl_pkts = 0;
+	u64 pkt_compl_bytes = 0;
+	u64 pkt_compl_pkts = 0;
+
+	/* Limit in order to avoid blocking for too long */
+	while (!napi || pkt_compl_pkts < napi->weight) {
+		struct gve_tx_compl_desc *compl_desc =
+			&tx->dqo.compl_ring[tx->dqo_compl.head];
+		u16 type;
+
+		if (compl_desc->generation == tx->dqo_compl.cur_gen_bit)
+			break;
+
+		/* Prefetch the next descriptor. */
+		prefetch(&tx->dqo.compl_ring[(tx->dqo_compl.head + 1) &
+				tx->dqo.complq_mask]);
+
+		/* Do not read data until we own the descriptor */
+		dma_rmb();
+		type = compl_desc->type;
+
+		if (type == GVE_COMPL_TYPE_DQO_DESC) {
+			/* This is the last descriptor fetched by HW plus one */
+			u16 tx_head = le16_to_cpu(compl_desc->tx_head);
+
+			atomic_set_release(&tx->dqo_compl.hw_tx_head, tx_head);
+		} else if (type == GVE_COMPL_TYPE_DQO_PKT) {
+			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
+
+			gve_handle_packet_completion(priv, tx, !!napi,
+						     compl_tag,
+						     &pkt_compl_bytes,
+						     &pkt_compl_pkts,
+						     /*is_reinjection=*/false);
+		} else if (type == GVE_COMPL_TYPE_DQO_MISS) {
+			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
+
+			gve_handle_miss_completion(priv, tx, compl_tag,
+						   &miss_compl_bytes,
+						   &miss_compl_pkts);
+		} else if (type == GVE_COMPL_TYPE_DQO_REINJECTION) {
+			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
+
+			gve_handle_packet_completion(priv, tx, !!napi,
+						     compl_tag,
+						     &reinject_compl_bytes,
+						     &reinject_compl_pkts,
+						     /*is_reinjection=*/true);
+		}
+
+		tx->dqo_compl.head =
+			(tx->dqo_compl.head + 1) & tx->dqo.complq_mask;
+		/* Flip the generation bit when we wrap around */
+		tx->dqo_compl.cur_gen_bit ^= tx->dqo_compl.head == 0;
+		num_descs_cleaned++;
+	}
+
+	netdev_tx_completed_queue(tx->netdev_txq,
+				  pkt_compl_pkts + miss_compl_pkts,
+				  pkt_compl_bytes + miss_compl_bytes);
+
+	remove_miss_completions(priv, tx);
+	remove_timed_out_completions(priv, tx);
+
+	u64_stats_update_begin(&tx->statss);
+	tx->bytes_done += pkt_compl_bytes + reinject_compl_bytes;
+	tx->pkt_done += pkt_compl_pkts + reinject_compl_pkts;
+	u64_stats_update_end(&tx->statss);
+	return num_descs_cleaned;
+}
+
+bool gve_tx_poll_dqo(struct gve_notify_block *block, bool do_clean)
+{
+	struct gve_tx_compl_desc *compl_desc;
+	struct gve_tx_ring *tx = block->tx;
+	struct gve_priv *priv = block->priv;
+
+	if (do_clean) {
+		int num_descs_cleaned = gve_clean_tx_done_dqo(priv, tx,
+							      &block->napi);
+
+		/* Sync with queue being stopped in `gve_maybe_stop_tx_dqo()` */
+		mb();
+
+		if (netif_tx_queue_stopped(tx->netdev_txq) &&
+		    num_descs_cleaned > 0) {
+			tx->wake_queue++;
+			netif_tx_wake_queue(tx->netdev_txq);
+		}
+	}
+
+	/* Return true if we still have work. */
+	compl_desc = &tx->dqo.compl_ring[tx->dqo_compl.head];
+	return compl_desc->generation != tx->dqo_compl.cur_gen_bit;
+}

drivers/net/ethernet/google/gve/gve_utils.c

+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/* Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+#include "gve.h"
+#include "gve_adminq.h"
+#include "gve_utils.h"
+
+void gve_tx_remove_from_block(struct gve_priv *priv, int queue_idx)
+{
+	struct gve_notify_block *block =
+			&priv->ntfy_blocks[gve_tx_idx_to_ntfy(priv, queue_idx)];
+
+	block->tx = NULL;
+}
+
+void gve_tx_add_to_block(struct gve_priv *priv, int queue_idx)
+{
+	int ntfy_idx = gve_tx_idx_to_ntfy(priv, queue_idx);
+	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
+	struct gve_tx_ring *tx = &priv->tx[queue_idx];
+
+	block->tx = tx;
+	tx->ntfy_id = ntfy_idx;
+}
+
+void gve_rx_remove_from_block(struct gve_priv *priv, int queue_idx)
+{
+	struct gve_notify_block *block =
+			&priv->ntfy_blocks[gve_rx_idx_to_ntfy(priv, queue_idx)];
+
+	block->rx = NULL;
+}
+
+void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx)
+{
+	u32 ntfy_idx = gve_rx_idx_to_ntfy(priv, queue_idx);
+	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
+	struct gve_rx_ring *rx = &priv->rx[queue_idx];
+
+	block->rx = rx;
+	rx->ntfy_id = ntfy_idx;
+}
+
+struct sk_buff *gve_rx_copy(struct net_device *dev, struct napi_struct *napi,
+			    struct gve_rx_slot_page_info *page_info, u16 len,
+			    u16 pad)
+{
+	struct sk_buff *skb = napi_alloc_skb(napi, len);
+	void *va = page_info->page_address + pad +
+		   page_info->page_offset;
+
+	if (unlikely(!skb))
+		return NULL;
+
+	__skb_put(skb, len);
+
+	skb_copy_to_linear_data(skb, va, len);
+
+	skb->protocol = eth_type_trans(skb, dev);
+
+	return skb;
+}
+
+void gve_dec_pagecnt_bias(struct gve_rx_slot_page_info *page_info)
+{
+	page_info->pagecnt_bias--;
+	if (page_info->pagecnt_bias == 0) {
+		int pagecount = page_count(page_info->page);
+
+		/* If we have run out of bias - set it back up to INT_MAX
+		 * minus the existing refs.
+		 */
+		page_info->pagecnt_bias = INT_MAX - pagecount;
+
+		/* Set pagecount back up to max. */
+		page_ref_add(page_info->page, INT_MAX - pagecount);
+	}
+}

drivers/net/ethernet/google/gve/gve_utils.h

+/* SPDX-License-Identifier: (GPL-2.0 OR MIT)
+ * Google virtual Ethernet (gve) driver
+ *
+ * Copyright (C) 2015-2021 Google, Inc.
+ */
+
+#ifndef _GVE_UTILS_H
+#define _GVE_UTILS_H
+
+#include <linux/etherdevice.h>
+
+#include "gve.h"
+
+void gve_tx_remove_from_block(struct gve_priv *priv, int queue_idx);
+void gve_tx_add_to_block(struct gve_priv *priv, int queue_idx);
+
+void gve_rx_remove_from_block(struct gve_priv *priv, int queue_idx);
+void gve_rx_add_to_block(struct gve_priv *priv, int queue_idx);
+
+struct sk_buff *gve_rx_copy(struct net_device *dev, struct napi_struct *napi,
+			    struct gve_rx_slot_page_info *page_info, u16 len,
+			    u16 pad);
+
+/* Decrement pagecnt_bias. Set it back to INT_MAX if it reached zero. */
+void gve_dec_pagecnt_bias(struct gve_rx_slot_page_info *page_info);
+
+#endif /* _GVE_UTILS_H */
+