Re: [PATCH V2 6/9] iommufd: file mappings for mdev

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Sep 24, 2024 at 08:05:35AM -0700, Steve Sistare wrote:
> Support file mappings for mediated devices, aka mdevs.  Access is initiated
> by the vfio_pin_pages and vfio_dma_rw kernel interfaces.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  drivers/iommu/iommufd/pages.c | 22 +++++++++++++++-------
>  1 file changed, 15 insertions(+), 7 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

> @@ -1884,6 +1884,9 @@ static int iopt_pages_rw_page(struct iopt_pages *pages, unsigned long index,
>  	struct page *page = NULL;
>  	int rc;
>  
> +	if (WARN_ON(pages->type != IOPT_ADDRESS_USER))
> +		return -EINVAL;

You can can probably wrap this with 
  if (IS_ENABLED(CONFIG_IOMMUFD_TEST))

since it is supposed to be fast path

Jason