diff mbox series

[1/2] vdpa/mlx5: workaround FW first completion in start

Message ID 20210923081758.178745-1-xuemingl@nvidia.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series [1/2] vdpa/mlx5: workaround FW first completion in start |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Xueming Li Sept. 23, 2021, 8:17 a.m. UTC 
  After a vDPA application restart, qemu restores VQ with used and
available index, new incoming packet triggers virtio driver to
handle buffers. Under heavy traffic, no available buffer for
firmware to receive new packets, no Rx interrupts generated,
driver is stuck on endless interrupt waiting.

As a firmware workaround, this patch sends a notification after
VQ setup to ask driver handling buffers and filling new buffers.

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Reviewed-by: Matan Azrad <matan@nvidia.com>
---
 drivers/vdpa/mlx5/mlx5_vdpa_virtq.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Maxime Coquelin Oct. 13, 2021, 9:55 a.m. UTC | #1 
Hi Xueming,

On 9/23/21 10:17, Xueming Li wrote:
> After a vDPA application restart, qemu restores VQ with used and
> available index, new incoming packet triggers virtio driver to
> handle buffers. Under heavy traffic, no available buffer for
> firmware to receive new packets, no Rx interrupts generated,
> driver is stuck on endless interrupt waiting.
> 
> As a firmware workaround, this patch sends a notification after
> VQ setup to ask driver handling buffers and filling new buffers.
> 
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> Reviewed-by: Matan Azrad <matan@nvidia.com>
> ---
>   drivers/vdpa/mlx5/mlx5_vdpa_virtq.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c b/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
> index f530646058..71470d23d9 100644
> --- a/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
> +++ b/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
> @@ -4,6 +4,7 @@
>   #include <string.h>
>   #include <unistd.h>
>   #include <sys/mman.h>
> +#include <sys/eventfd.h>
>   
>   #include <rte_malloc.h>
>   #include <rte_errno.h>
> @@ -367,6 +368,9 @@ mlx5_vdpa_virtq_setup(struct mlx5_vdpa_priv *priv, int index)
>   		goto error;
>   	}
>   	virtq->stopped = false;
> +	/* Initial notification to ask qemu handling completed buffers. */
> +	if (virtq->eqp.cq.callfd != -1)
> +		eventfd_write(virtq->eqp.cq.callfd, (eventfd_t)1);
>   	DRV_LOG(DEBUG, "vid %u virtq %u was created successfully.", priv->vid,
>   		index);
>   	return 0;
> 

Maybe this patch should be backported to stable branch?
If so, could you reply with the Fixes tag so that I can add it while
applying?

Thanks,
Maxime
diff mbox series

Patch

diff --git a/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c b/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
index f530646058..71470d23d9 100644
--- a/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
+++ b/drivers/vdpa/mlx5/mlx5_vdpa_virtq.c
@@ -4,6 +4,7 @@ 
 #include <string.h>
 #include <unistd.h>
 #include <sys/mman.h>
+#include <sys/eventfd.h>
 
 #include <rte_malloc.h>
 #include <rte_errno.h>
@@ -367,6 +368,9 @@  mlx5_vdpa_virtq_setup(struct mlx5_vdpa_priv *priv, int index)
 		goto error;
 	}
 	virtq->stopped = false;
+	/* Initial notification to ask qemu handling completed buffers. */
+	if (virtq->eqp.cq.callfd != -1)
+		eventfd_write(virtq->eqp.cq.callfd, (eventfd_t)1);
 	DRV_LOG(DEBUG, "vid %u virtq %u was created successfully.", priv->vid,
 		index);
 	return 0;