vdpa/mlx5: Allow CVQ size changes

[ Upstream commit 749a4016839270163efc36ecddddd01de491a16b ]

The MLX driver was not updating its control virtqueue size at set_vq_num
and instead always initialize

vdpa/mlx5: Allow CVQ size changes

[ Upstream commit 749a4016839270163efc36ecddddd01de491a16b ]

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@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Message-Id: <20240216142502.78095-1-jonah.palmer@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Fixes: 5262912ef3cf ("vdpa/mlx5: Add support for control VQ and MAC setting")
Signed-off-by: Sasha Levin <sashal@kernel.org>

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vdpa/mlx5: preserve CVQ vringh index

[ Upstream commit 480b3e73720f6b5d76bef2387b1f9d19ed67573b ]

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

vdpa/mlx5: preserve CVQ vringh index

[ Upstream commit 480b3e73720f6b5d76bef2387b1f9d19ed67573b ]

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>
Message-Id: <1699014387-194368-1-git-send-email-steven.sistare@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...