nvme: add spdk_nvme_map_cmd API

The API `spdk_nvme_map_prps` is used in nvmf/vfio-user to
remap VM's NVMe command data buffer to local virtual address,
and for command using PRP, there maybe multiple pages, when
parsing the PRP list to local IOVs, we need a parameter to check
that the maximum number of vectors can't exceed the IOVs, this API
can't meet the requirement, while here, we add a new API `spdk_nvme_map_cmd`
and with a new parameter `max_iovcnt` to fix this case, and it can
also cover the command using SGL in the coming patches.

Change-Id: I71063524bed16ee3434103867a556d3741e55326
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7278
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Community-CI: Broadcom CI
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

CHANGELOG.md

@@ -17,6 +17,8 @@ Added an accelerated table pointer in spdk_nvme_poll_group
 which can be used provide the accelerated functions by users with
 hardware engine, such as crc32c accelerated function.
 
+Added `spdk_nvme_map_cmd` API to map the NVMe command with SGL cases.
+
 ### raid
 
 For `bdev_raid_create` RPC, the deprecated parameter `strip_size` was removed.

include/spdk/nvme.h

@@ -3472,6 +3472,21 @@ int spdk_nvme_map_prps(void *prv, struct spdk_nvme_cmd *cmd, struct iovec *iovs,
 		       uint32_t len, size_t mps,
 		       void *(*gpa_to_vva)(void *prv, uint64_t addr, uint64_t len));
 
+/**
+ * Map NVMe command data buffers sent from Virtual Machine to virtual addresses
+ *
+ *\param prv Opaque handle to gpa_to_vva callback
+ *\param cmd NVMe command
+ *\param iovs IO vectors used to point the data buffers in NVMe command
+ *\param max_iovcnt Maximum IO vectors that can be used
+ *\param len Total buffer length for the NVMe command
+ *\param mps Memory page size
+ *\param gpa_to_vva Callback to map memory from Guest Physical address to Virtual address
+ */
+int spdk_nvme_map_cmd(void *prv, struct spdk_nvme_cmd *cmd, struct iovec *iovs, uint32_t max_iovcnt,
+		      uint32_t len, size_t mps,
+		      void *(*gpa_to_vva)(void *prv, uint64_t addr, uint64_t len));
+
 /**
  * Opaque handle for a transport poll group. Used by the transport function table.
  */

lib/nvme/nvme_ctrlr.c

@@ -4273,3 +4273,15 @@ spdk_nvme_map_prps(void *prv, struct spdk_nvme_cmd *cmd, struct iovec *iovs,
 
 	return -EINVAL;
 }
+
+int
+spdk_nvme_map_cmd(void *prv, struct spdk_nvme_cmd *cmd, struct iovec *iovs, uint32_t max_iovcnt,
+		  uint32_t len, size_t mps,
+		  void *(*gpa_to_vva)(void *prv, uint64_t addr, uint64_t len))
+{
+	if (cmd->psdt == SPDK_NVME_PSDT_PRP) {
+		return nvme_cmd_map_prps(prv, cmd, iovs, max_iovcnt, len, mps, gpa_to_vva);
+	}
+
+	return -EINVAL;
+}

lib/nvme/spdk_nvme.map

@@ -167,6 +167,7 @@
 	spdk_nvme_cuse_update_namespaces;
 
 	spdk_nvme_map_prps;
+	spdk_nvme_map_cmd;
 
 	spdk_nvme_poll_group_get_stats;
 	spdk_nvme_poll_group_free_stats;

lib/nvmf/vfio_user.c

@@ -559,8 +559,8 @@ vfio_user_map_prps(struct nvmf_vfio_user_ctrlr *ctrlr, struct spdk_nvmf_request
 	/* Map PRP list to from Guest physical memory to
 	 * virtual memory address.
 	 */
-	return spdk_nvme_map_prps(req, &req->cmd->nvme_cmd, iov, length,
-				  4096, _map_one);
+	return spdk_nvme_map_cmd(req, &req->cmd->nvme_cmd, iov, NVMF_REQ_MAX_BUFFERS,
+				 length, 4096, _map_one);
 }
 
 static struct spdk_nvmf_request *