Re: [PATCH v5 5/6] drm/xe/vf: Add bounds checking for queried VRAM size

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 8/10/2026 12:14 PM, Satyanarayana K V P wrote:
> Add explicit bounds checks for VRAM size which can detect and reject
> invalid configuration data from a misconfigured or malfunctioning PF,
> preventing protocol violations and protecting VF initialization.
> 
> Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> ---
> V4 -> V5:
> - New commit.
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> index 65e48f135801..6c1878e4b1b2 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> @@ -575,7 +575,7 @@ static int vf_get_lmem_info(struct xe_gt *gt)
>  		return err;
>  
>  	lmem_size = xe_tile_sriov_vf_lmem(tile);
> -	if (lmem_size && lmem_size != size) {
> +	if ((lmem_size && lmem_size != size) || (size % SZ_2M)) {

IS_ALIGNED(size, SZ_2M)

and since those are two different conditions, they deserve different
error codes and different message (-EREMCHG for reassignment and
-EPROTO or maybe better -EINVAL if unaligned)
>  		xe_gt_sriov_err(gt, "Unexpected LMEM reassignment: %lluM != %lluM\n",
>  				size / SZ_1M, lmem_size / SZ_1M);
>  		return -EREMCHG;