[PATCH V3] vdpa/mlx5: preserve CVQ vringh index

Steve Sistare
2023-11-03T12:26:48Z

mlx5_vdpa does not preserve userland's view of vring base for the control
queue in the following sequence:

ioctl VHOST_SET_VRING_BASE
ioctl VHOST_VDPA_SET_STATUS VIRTIO_CONFIG_S_DRIVER_OK
mlx5_vdpa_set_status()
setup_cvq_vring()
vringh_init_iotlb()
vringh_init_kern()
vrh->last_avail_idx = 0;
ioctl VHOST_GET_VRING_BASE

To fix, restore the value of cvq->vring.last_avail_idx after calling
vringh_init_iotlb.

Fixes: 5262912ef3cf ("vdpa/mlx5: Add support for control VQ and MAC setting")

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 946488b8989f..ca972af3c89a 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2795,13 +2795,18 @@ static int setup_cvq_vring(struct mlx5_vdpa_dev *mvdev)
struct mlx5_control_vq *cvq = &mvdev->cvq;
int err = 0;

- if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
+ if (mvdev->actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ)) {
+ u16 idx = cvq->vring.last_avail_idx;
+
err = vringh_init_iotlb(&cvq->vring, mvdev->actual_features,
MLX5_CVQ_MAX_ENT, 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);

+ if (!err)
+ cvq->vring.last_avail_idx = cvq->vring.last_used_idx = idx;
+ }
return err;
}

--
2.39.3

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