habanalabs: add userptr_lookup node in debugfs

It is useful to have the ability to see which user address was pinned
to which physical address during the initial mapping. We already have
all that info stored, but no means to search this data (which may be
quite large).
Signed-off-by: Yuri Nudelman <ynudelman@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

Documentation/ABI/testing/debugfs-driver-habanalabs

@@ -241,6 +241,14 @@ Description:    Displays a list with information about the currently user
                 pointers (user virtual addresses) that are pinned and mapped
                 to DMA addresses
 
+What:           /sys/kernel/debug/habanalabs/hl<n>/userptr_lookup
+Date:           Aug 2021
+KernelVersion:  5.15
+Contact:        ogabbay@kernel.org
+Description:    Allows to search for specific user pointers (user virtual
+                addresses) that are pinned and mapped to DMA addresses, and see
+                their resolution to the specific dma address.
+
 What:           /sys/kernel/debug/habanalabs/hl<n>/vm
 Date:           Jan 2019
 KernelVersion:  5.1

drivers/misc/habanalabs/common/debugfs.c

@@ -320,6 +320,77 @@ static int vm_show(struct seq_file *s, void *data)
 	return 0;
 }
 
+static int userptr_lookup_show(struct seq_file *s, void *data)
+{
+	struct hl_debugfs_entry *entry = s->private;
+	struct hl_dbg_device_entry *dev_entry = entry->dev_entry;
+	struct scatterlist *sg;
+	struct hl_userptr *userptr;
+	bool first = true;
+	u64 total_npages, npages, sg_start, sg_end;
+	dma_addr_t dma_addr;
+	int i;
+
+	spin_lock(&dev_entry->userptr_spinlock);
+
+	list_for_each_entry(userptr, &dev_entry->userptr_list, debugfs_list) {
+		if (dev_entry->userptr_lookup >= userptr->addr &&
+		dev_entry->userptr_lookup < userptr->addr + userptr->size) {
+			total_npages = 0;
+			for_each_sg(userptr->sgt->sgl, sg, userptr->sgt->nents,
+					i) {
+				npages = hl_get_sg_info(sg, &dma_addr);
+				sg_start = userptr->addr +
+					total_npages * PAGE_SIZE;
+				sg_end = userptr->addr +
+					(total_npages + npages) * PAGE_SIZE;
+
+				if (dev_entry->userptr_lookup >= sg_start &&
+				    dev_entry->userptr_lookup < sg_end) {
+					dma_addr += (dev_entry->userptr_lookup -
+							sg_start);
+					if (first) {
+						first = false;
+						seq_puts(s, "\n");
+						seq_puts(s, " user virtual address         dma address       pid        region start     region size\n");
+						seq_puts(s, "---------------------------------------------------------------------------------------\n");
+					}
+					seq_printf(s, " 0x%-18llx  0x%-16llx  %-8u  0x%-16llx %-12llu\n",
+						dev_entry->userptr_lookup,
+						(u64)dma_addr, userptr->pid,
+						userptr->addr, userptr->size);
+				}
+				total_npages += npages;
+			}
+		}
+	}
+
+	spin_unlock(&dev_entry->userptr_spinlock);
+
+	if (!first)
+		seq_puts(s, "\n");
+
+	return 0;
+}
+
+static ssize_t userptr_lookup_write(struct file *file, const char __user *buf,
+		size_t count, loff_t *f_pos)
+{
+	struct seq_file *s = file->private_data;
+	struct hl_debugfs_entry *entry = s->private;
+	struct hl_dbg_device_entry *dev_entry = entry->dev_entry;
+	ssize_t rc;
+	u64 value;
+
+	rc = kstrtoull_from_user(buf, count, 16, &value);
+	if (rc)
+		return rc;
+
+	dev_entry->userptr_lookup = value;
+
+	return count;
+}
+
 static int mmu_show(struct seq_file *s, void *data)
 {
 	struct hl_debugfs_entry *entry = s->private;
@@ -1175,6 +1246,7 @@ static const struct hl_info_list hl_debugfs_list[] = {
 	{"command_submission_jobs", command_submission_jobs_show, NULL},
 	{"userptr", userptr_show, NULL},
 	{"vm", vm_show, NULL},
+	{"userptr_lookup", userptr_lookup_show, userptr_lookup_write},
 	{"mmu", mmu_show, mmu_asid_va_write},
 	{"engines", engines_show, NULL}
 };

drivers/misc/habanalabs/common/habanalabs.h

@@ -1816,6 +1816,7 @@ struct hl_debugfs_entry {
  * @state_dump_sem: protects state_dump.
  * @addr: next address to read/write from/to in read/write32.
  * @mmu_addr: next virtual address to translate to physical address in mmu_show.
+ * @userptr_lookup: the target user ptr to look up for on demand.
  * @mmu_asid: ASID to use while translating in mmu_show.
  * @state_dump_head: index of the latest state dump
  * @i2c_bus: generic u8 debugfs file for bus value to use in i2c_data_read.
@@ -1843,6 +1844,7 @@ struct hl_dbg_device_entry {
 	struct rw_semaphore		state_dump_sem;
 	u64				addr;
 	u64				mmu_addr;
+	u64				userptr_lookup;
 	u32				mmu_asid;
 	u32				state_dump_head;
 	u8				i2c_bus;
@@ -2647,6 +2649,23 @@ struct hl_ioctl_desc {
  * Kernel module functions that can be accessed by entire module
  */
 
+/**
+ * hl_get_sg_info() - get number of pages and the DMA address from SG list.
+ * @sg: the SG list.
+ * @dma_addr: pointer to DMA address to return.
+ *
+ * Calculate the number of consecutive pages described by the SG list. Take the
+ * offset of the address in the first page, add to it the length and round it up
+ * to the number of needed pages.
+ */
+static inline u32 hl_get_sg_info(struct scatterlist *sg, dma_addr_t *dma_addr)
+{
+	*dma_addr = sg_dma_address(sg);
+
+	return ((((*dma_addr) & (PAGE_SIZE - 1)) + sg_dma_len(sg)) +
+			(PAGE_SIZE - 1)) >> PAGE_SHIFT;
+}
+
 /**
  * hl_mem_area_inside_range() - Checks whether address+size are inside a range.
  * @address: The start address of the area we want to validate.

drivers/misc/habanalabs/common/memory.c

@@ -796,23 +796,6 @@ int hl_unreserve_va_block(struct hl_device *hdev, struct hl_ctx *ctx,
 	return rc;
 }
 
-/**
- * get_sg_info() - get number of pages and the DMA address from SG list.
- * @sg: the SG list.
- * @dma_addr: pointer to DMA address to return.
- *
- * Calculate the number of consecutive pages described by the SG list. Take the
- * offset of the address in the first page, add to it the length and round it up
- * to the number of needed pages.
- */
-static u32 get_sg_info(struct scatterlist *sg, dma_addr_t *dma_addr)
-{
-	*dma_addr = sg_dma_address(sg);
-
-	return ((((*dma_addr) & (PAGE_SIZE - 1)) + sg_dma_len(sg)) +
-			(PAGE_SIZE - 1)) >> PAGE_SHIFT;
-}
-
 /**
  * init_phys_pg_pack_from_userptr() - initialize physical page pack from host
  *                                    memory
@@ -863,7 +846,7 @@ static int init_phys_pg_pack_from_userptr(struct hl_ctx *ctx,
 	 */
 	total_npages = 0;
 	for_each_sg(userptr->sgt->sgl, sg, userptr->sgt->nents, i) {
-		npages = get_sg_info(sg, &dma_addr);
+		npages = hl_get_sg_info(sg, &dma_addr);
 
 		total_npages += npages;
 
@@ -892,7 +875,7 @@ static int init_phys_pg_pack_from_userptr(struct hl_ctx *ctx,
 
 	j = 0;
 	for_each_sg(userptr->sgt->sgl, sg, userptr->sgt->nents, i) {
-		npages = get_sg_info(sg, &dma_addr);
+		npages = hl_get_sg_info(sg, &dma_addr);
 
 		/* align down to physical page size and save the offset */
 		if (first) {