[PATCH 6.6 607/638] vdpa/mlx5: Allow CVQ size changes

Sasha Levin
2024-03-24T23:11:19Z

From: Jonah Palmer <jonah.palmer@oracle.com>

[ 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>
---
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 ca972af3c89a2..b56aae3f7be37 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -144,8 +144,6 @@ 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)) \
@@ -2136,9 +2134,16 @@ 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;
}
@@ -2799,7 +2804,7 @@ 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);
--
2.43.0