vDPA/ifcvf: virt queue ops take immediate actions

In this commit, virtqueue operations including:
set_vq_num(), set_vq_address(), set_vq_ready()
and get_vq_ready() access PCI registers directly
to take immediate actions.
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230526145254.39537-2-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/ifcvf/ifcvf_base.c

@@ -329,31 +329,49 @@ int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num)
 	return 0;
 }
 
-static int ifcvf_hw_enable(struct ifcvf_hw *hw)
+void ifcvf_set_vq_num(struct ifcvf_hw *hw, u16 qid, u32 num)
 {
-	struct virtio_pci_common_cfg __iomem *cfg;
-	u32 i;
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
 
-	cfg = hw->common_cfg;
-	for (i = 0; i < hw->nr_vring; i++) {
-		if (!hw->vring[i].ready)
-			break;
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite16(num, &cfg->queue_size);
+}
+
+int ifcvf_set_vq_address(struct ifcvf_hw *hw, u16 qid, u64 desc_area,
+			 u64 driver_area, u64 device_area)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
 
-		vp_iowrite16(i, &cfg->queue_select);
-		vp_iowrite64_twopart(hw->vring[i].desc, &cfg->queue_desc_lo,
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite64_twopart(desc_area, &cfg->queue_desc_lo,
 			     &cfg->queue_desc_hi);
-		vp_iowrite64_twopart(hw->vring[i].avail, &cfg->queue_avail_lo,
+	vp_iowrite64_twopart(driver_area, &cfg->queue_avail_lo,
 			     &cfg->queue_avail_hi);
-		vp_iowrite64_twopart(hw->vring[i].used, &cfg->queue_used_lo,
+	vp_iowrite64_twopart(device_area, &cfg->queue_used_lo,
 			     &cfg->queue_used_hi);
-		vp_iowrite16(hw->vring[i].size, &cfg->queue_size);
-		ifcvf_set_vq_state(hw, i, hw->vring[i].last_avail_idx);
-		vp_iowrite16(1, &cfg->queue_enable);
-	}
 
 	return 0;
 }
 
+bool ifcvf_get_vq_ready(struct ifcvf_hw *hw, u16 qid)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
+	u16 queue_enable;
+
+	vp_iowrite16(qid, &cfg->queue_select);
+	queue_enable = vp_ioread16(&cfg->queue_enable);
+
+	return (bool)queue_enable;
+}
+
+void ifcvf_set_vq_ready(struct ifcvf_hw *hw, u16 qid, bool ready)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
+
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite16(ready, &cfg->queue_enable);
+}
+
 static void ifcvf_hw_disable(struct ifcvf_hw *hw)
 {
 	u32 i;
@@ -366,16 +384,12 @@ static void ifcvf_hw_disable(struct ifcvf_hw *hw)
 
 int ifcvf_start_hw(struct ifcvf_hw *hw)
 {
-	ifcvf_reset(hw);
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_ACKNOWLEDGE);
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER);
 
 	if (ifcvf_config_features(hw) < 0)
 		return -EINVAL;
 
-	if (ifcvf_hw_enable(hw) < 0)
-		return -EINVAL;
-
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER_OK);
 
 	return 0;

drivers/vdpa/ifcvf/ifcvf_base.h

@@ -47,12 +47,7 @@
 #define MSIX_VECTOR_DEV_SHARED			3
 
 struct vring_info {
-	u64 desc;
-	u64 avail;
-	u64 used;
-	u16 size;
 	u16 last_avail_idx;
-	bool ready;
 	void __iomem *notify_addr;
 	phys_addr_t notify_pa;
 	u32 irq;
@@ -137,4 +132,9 @@ int ifcvf_probed_virtio_net(struct ifcvf_hw *hw);
 u32 ifcvf_get_config_size(struct ifcvf_hw *hw);
 u16 ifcvf_set_vq_vector(struct ifcvf_hw *hw, u16 qid, int vector);
 u16 ifcvf_set_config_vector(struct ifcvf_hw *hw, int vector);
+void ifcvf_set_vq_num(struct ifcvf_hw *hw, u16 qid, u32 num);
+int ifcvf_set_vq_address(struct ifcvf_hw *hw, u16 qid, u64 desc_area,
+			 u64 driver_area, u64 device_area);
+bool ifcvf_get_vq_ready(struct ifcvf_hw *hw, u16 qid);
+void ifcvf_set_vq_ready(struct ifcvf_hw *hw, u16 qid, bool ready);
 #endif /* _IFCVF_H_ */

drivers/vdpa/ifcvf/ifcvf_main.c

@@ -382,10 +382,6 @@ static void ifcvf_reset_vring(struct ifcvf_adapter *adapter)
 
 	for (i = 0; i < vf->nr_vring; i++) {
 		vf->vring[i].last_avail_idx = 0;
-		vf->vring[i].desc = 0;
-		vf->vring[i].avail = 0;
-		vf->vring[i].used = 0;
-		vf->vring[i].ready = 0;
 		vf->vring[i].cb.callback = NULL;
 		vf->vring[i].cb.private = NULL;
 	}
@@ -542,14 +538,14 @@ static void ifcvf_vdpa_set_vq_ready(struct vdpa_device *vdpa_dev,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	vf->vring[qid].ready = ready;
+	ifcvf_set_vq_ready(vf, qid, ready);
 }
 
 static bool ifcvf_vdpa_get_vq_ready(struct vdpa_device *vdpa_dev, u16 qid)
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	return vf->vring[qid].ready;
+	return ifcvf_get_vq_ready(vf, qid);
 }
 
 static void ifcvf_vdpa_set_vq_num(struct vdpa_device *vdpa_dev, u16 qid,
@@ -557,7 +553,7 @@ static void ifcvf_vdpa_set_vq_num(struct vdpa_device *vdpa_dev, u16 qid,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	vf->vring[qid].size = num;
+	ifcvf_set_vq_num(vf, qid, num);
 }
 
 static int ifcvf_vdpa_set_vq_address(struct vdpa_device *vdpa_dev, u16 qid,
@@ -566,11 +562,7 @@ static int ifcvf_vdpa_set_vq_address(struct vdpa_device *vdpa_dev, u16 qid,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	vf->vring[qid].desc = desc_area;
-	vf->vring[qid].avail = driver_area;
-	vf->vring[qid].used = device_area;
-
-	return 0;
+	return ifcvf_set_vq_address(vf, qid, desc_area, driver_area, device_area);
 }
 
 static void ifcvf_vdpa_kick_vq(struct vdpa_device *vdpa_dev, u16 qid)