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

[Steven Sistare]

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@xxxxxxxxxx>
>>> Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
>>> Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
>>> ---
>>>  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;
>>>  }
>>>  
>