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

Steven Sistare
2023-12-04T13:52:56Z

Glad to hear it, thanks - Steve

On 12/4/2023 8:35 AM, Michael S. Tsirkin wrote:
> It's in my tee and I'm sending it to Linus.
>
> On Mon, Dec 04, 2023 at 08:33:22AM -0500, Steven Sistare wrote:
>> What's the decision here, pull it, or do not fix it?
>>
>> - Steve
>>
>> On 11/3/2023 8:26 AM, Steve Sistare wrote:
>>> 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;
>>> }
>>>
>