RE: [PATCH v3 1/5] vfio: Do not allow !ops->dma_unmap in vfio_pin/unpin_pages()

["Liu, Yi L" <yi.l.liu@intel.com>]

> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Saturday, February 25, 2023 9:52 AM
> 
> A driver that doesn't implement ops->dma_unmap shouldn't be allowed to
> do
> vfio_pin/unpin_pages(), though it can use vfio_dma_rw() to access an iova
> range. Deny !ops->dma_unmap cases in vfio_pin/unpin_pages().
> 
> Suggested-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>

Reviewed-by: Yi Liu <yi.l.liu@intel.com>

> ---
>  drivers/vfio/vfio_main.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index 43bd6b76e2b6..0381f6e7f4e6 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -1292,6 +1292,8 @@ int vfio_pin_pages(struct vfio_device *device,
> dma_addr_t iova,
>  	/* group->container cannot change while a vfio device is open */
>  	if (!pages || !npage ||
> WARN_ON(!vfio_assert_device_open(device)))
>  		return -EINVAL;
> +	if (!device->ops->dma_unmap)
> +		return -EINVAL;
>  	if (vfio_device_has_container(device))
>  		return vfio_device_container_pin_pages(device, iova,
>  						       npage, prot, pages);
> @@ -1329,6 +1331,8 @@ void vfio_unpin_pages(struct vfio_device *device,
> dma_addr_t iova, int npage)
>  {
>  	if (WARN_ON(!vfio_assert_device_open(device)))
>  		return;
> +	if (WARN_ON(!device->ops->dma_unmap))
> +		return;
> 
>  	if (vfio_device_has_container(device)) {
>  		vfio_device_container_unpin_pages(device, iova, npage);
> --
> 2.39.2