QE tested this patch's V2, qemu no longer print error messages
"qemu-system-x86_64: Insufficient written data (0)" after
enable/disable multi queues multi times inside guest. Both "x-svq=on
'' and without it are all test pass.
Tested-by: Lei Yang <leiyang@xxxxxxxxxx>
On Fri, Feb 16, 2024 at 10:25 PM Jonah Palmer <jonah.palmer@xxxxxxxxxx> wrote:
>
> The MLX driver was not updating its control virtqueue size at set_vq_num
> and instead always initialized to MLX5_CVQ_MAX_ENT (16) at
> setup_cvq_vring.
>
> Qemu would try to set the size to 64 by default, however, because the
> CVQ size always was initialized to 16, an error would be thrown when
> sending >16 control messages (as used-ring entry 17 is initialized to 0).
> For example, starting a guest with x-svq=on and then executing the
> following command would produce the error below:
>
> # for i in {1..20}; do ifconfig eth0 hw ether XX:xx:XX:xx:XX:XX; done
>
> qemu-system-x86_64: Insufficient written data (0)
> [ 435.331223] virtio_net virtio0: Failed to set mac address by vq command.
> SIOCSIFHWADDR: Invalid argument
>
> Acked-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> Signed-off-by: Jonah Palmer <jonah.palmer@xxxxxxxxxx>
> ---
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 778821bab7d9..ecfc16151d61 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -151,8 +151,6 @@ static void teardown_driver(struct mlx5_vdpa_net *ndev);
>
> static bool mlx5_vdpa_debug;
>
> -#define MLX5_CVQ_MAX_ENT 16
> -
> #define MLX5_LOG_VIO_FLAG(_feature) \
> do { \
> if (features & BIT_ULL(_feature)) \
> @@ -2276,9 +2274,16 @@ static void mlx5_vdpa_set_vq_num(struct vdpa_device *vdev, u16 idx, u32 num)
> struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> struct mlx5_vdpa_virtqueue *mvq;
>
> - if (!is_index_valid(mvdev, idx) || is_ctrl_vq_idx(mvdev, idx))
> + if (!is_index_valid(mvdev, idx))
> return;
>
> + if (is_ctrl_vq_idx(mvdev, idx)) {
> + struct mlx5_control_vq *cvq = &mvdev->cvq;
> +
> + cvq->vring.vring.num = num;
> + return;
> + }
> +
> mvq = &ndev->vqs[idx];
> mvq->num_ent = num;
> }
> @@ -2963,7 +2968,7 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
> u16 idx = cvq->vring.last_avail_idx;
>
> err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
> - MLX5_CVQ_MAX_ENT, false,
> + cvq->vring.vring.num, false,
> (struct vring_desc *)(uintptr_t)cvq->desc_addr,
> (struct vring_avail *)(uintptr_t)cvq->driver_addr,
> (struct vring_used *)(uintptr_t)cvq->device_addr);
> --
> 2.39.3
>
