[v1,30/38] vdpa/mlx5: map doorbell
diff mbox series

Message ID 1579539790-3882-31-git-send-email-matan@mellanox.com
State Superseded
Delegated to: Maxime Coquelin
Headers show
Series
  • Introduce mlx5 vDPA driver
Related show

Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Matan Azrad Jan. 20, 2020, 5:03 p.m. UTC
The HW support only 4 bytes doorbell writing detection.
The virtio device set only 2 bytes when it rings the doorbell.

Map the virtio doorbell detected by the virtio queue kickfd to the HW
VAR space when it expects to get the virtio emulation doorbell.

Use the EAL interrupt mechanism to get notification when a new event
appears in kickfd by the guest and write 4 bytes to the HW doorbell space
in the notification callback.

Signed-off-by: Matan Azrad <matan@mellanox.com>
---
 drivers/vdpa/mlx5/mlx5_vdpa.h       |  3 ++
 drivers/vdpa/mlx5/mlx5_vdpa_virtq.c | 84 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 86 insertions(+), 1 deletion(-)

Patch
diff mbox series

diff --git a/drivers/vdpa/mlx5/mlx5_vdpa.h b/drivers/vdpa/mlx5/mlx5_vdpa.h
index 318f1e8..8503b7b 100644
--- a/drivers/vdpa/mlx5/mlx5_vdpa.h
+++ b/drivers/vdpa/mlx5/mlx5_vdpa.h
@@ -66,6 +66,7 @@  struct mlx5_vdpa_virtq {
 		void *buf;
 		uint32_t size;
 	} umems[3];
+	struct rte_intr_handle intr_handle;
 };
 
 struct mlx5_vdpa_steer {
@@ -103,6 +104,8 @@  struct mlx5_vdpa_priv {
 	uint16_t log_max_rqt_size;
 	SLIST_HEAD(virtq_list, mlx5_vdpa_virtq) virtq_list;
 	struct mlx5_vdpa_steer steer;
+	struct mlx5dv_var *var;
+	void *virtq_db_addr;
 	SLIST_HEAD(mr_list, mlx5_vdpa_query_mr) mr_list;
 };
 
diff --git a/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c b/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
index a294117..fbcf971 100644
--- a/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
+++ b/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
@@ -3,20 +3,65 @@ 
  */
 #include <string.h>
 #include <assert.h>
+#include <unistd.h>
+#include <sys/mman.h>
 
 #include <rte_malloc.h>
 #include <rte_errno.h>
+#include <rte_io.h>
 
 #include "mlx5_vdpa_utils.h"
 #include "mlx5_vdpa.h"
 
 
+static void
+mlx5_vdpa_virtq_handler(void *cb_arg)
+{
+	struct mlx5_vdpa_virtq *virtq = cb_arg;
+	struct mlx5_vdpa_priv *priv = virtq->priv;
+	uint64_t buf;
+	int nbytes;
+
+	do {
+		nbytes = read(virtq->intr_handle.fd, &buf, 8);
+		if (nbytes < 0) {
+			if (errno == EINTR ||
+			    errno == EWOULDBLOCK ||
+			    errno == EAGAIN)
+				continue;
+			DRV_LOG(ERR,  "Failed to read kickfd of virtq %d: %s",
+				virtq->index, strerror(errno));
+		}
+		break;
+	} while (1);
+	assert(priv->virtq_db_addr);
+	rte_write32(virtq->index, priv->virtq_db_addr);
+	DRV_LOG(DEBUG, "Ring virtq %u doorbell.", virtq->index);
+}
+
 static int
 mlx5_vdpa_virtq_unset(struct mlx5_vdpa_virtq *virtq)
 {
-	int ret __rte_unused;
 	unsigned i;
+	int retries = MLX5_VDPA_INTR_RETRIES;
+	int ret = -EAGAIN;
 
+	if (virtq->intr_handle.fd) {
+		while (retries-- && ret == -EAGAIN) {
+			ret = rte_intr_callback_unregister(&virtq->intr_handle,
+							mlx5_vdpa_virtq_handler,
+							virtq);
+			if (ret == -EAGAIN) {
+				DRV_LOG(DEBUG, "Try again to unregister fd %d "
+					"of virtq %d interrupt, retries = %d.",
+					virtq->intr_handle.fd,
+					(int)virtq->index, retries);
+				usleep(MLX5_VDPA_INTR_RETRIES_USEC);
+			}
+		}
+		assert(!ret);
+		memset(&virtq->intr_handle, 0, sizeof(virtq->intr_handle));
+	}
 	if (virtq->virtq) {
 		ret = mlx5_devx_cmd_destroy(virtq->virtq);
 		assert(!ret);
@@ -62,6 +107,15 @@ 
 		assert(!ret);
 		priv->td = NULL;
 	}
+	if (priv->virtq_db_addr) {
+		ret = munmap(priv->virtq_db_addr, priv->var->length);
+		assert(!ret);
+		priv->virtq_db_addr = NULL;
+	}
+	if (priv->var) {
+		mlx5_glue->dv_free_var(priv->var);
+		priv->var = NULL;
+	}
 	priv->features = 0;
 }
 
@@ -207,6 +261,17 @@ 
 	if (mlx5_vdpa_virtq_modify(virtq, 1))
 		goto error;
 	virtq->enable = 1;
+	virtq->intr_handle.fd = vq.kickfd;
+	virtq->intr_handle.type = RTE_INTR_HANDLE_EXT;
+	if (rte_intr_callback_register(&virtq->intr_handle,
+				       mlx5_vdpa_virtq_handler, virtq)) {
+		virtq->intr_handle.fd = 0;
+		DRV_LOG(ERR, "Failed to register virtq %d interrupt.", index);
+		goto error;
+	} else {
+		DRV_LOG(DEBUG, "Register fd %d interrupt for virtq %d.",
+			virtq->intr_handle.fd, index);
+	}
 	return 0;
 error:
 	mlx5_vdpa_virtq_unset(virtq);
@@ -281,6 +346,23 @@ 
 		DRV_LOG(ERR, "Failed to configure negotiated features.");
 		return -1;
 	}
+	priv->var = mlx5_glue->dv_alloc_var(priv->ctx, 0);
+	if (!priv->var) {
+		DRV_LOG(ERR, "Failed to allocate VAR %u.\n", errno);
+		return -1;
+	}
+	/* Always map the entire page. */
+	priv->virtq_db_addr = mmap(NULL, priv->var->length, PROT_READ |
+				   PROT_WRITE, MAP_SHARED, priv->ctx->cmd_fd,
+				   priv->var->mmap_off);
+	if (priv->virtq_db_addr == MAP_FAILED) {
+		DRV_LOG(ERR, "Failed to map doorbell page %u.", errno);
+		priv->virtq_db_addr = NULL;
+		goto error;
+	} else {
+		DRV_LOG(DEBUG, "VAR address of doorbell mapping is %p.",
+			priv->virtq_db_addr);
+	}
 	priv->td = mlx5_devx_cmd_create_td(priv->ctx);
 	if (!priv->td) {
 		DRV_LOG(ERR, "Failed to create transpprt domain.");