Re: [PATCH] drm/amdgpu: restrict BAR0 fallback read to SR-IOV VFs only

On Wed, Aug 26, 2026 at 4:10 PM Mario Limonciello
<[email protected]> wrote:
>
> The BAR0 fallback read path was introduced as a workaround for SR-IOV VFs
> where the VRAM aperture is not available during early init. Restrict this
> workaround to only SR-IOV VFs where it's needed.
>
> Cc: [email protected]
> Reported-by: [email protected]
> Fixes: ea8ac194077d ("drm/amdgpu: reduce early full GPU access during SR-IOV init")
> Signed-off-by: Mario Limonciello <[email protected]>

Acked-by: Alex Deucher <[email protected]>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 3603f7109703c..251c4aea013fc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -765,6 +765,9 @@ static int amdgpu_device_read_fb_via_bar0(struct amdgpu_device *adev,
>         if (!buf || !size)
>                 return -EINVAL;
>
> +       if (!amdgpu_sriov_vf(adev))
> +               return -EINVAL;
> +
>         flags = pci_resource_flags(adev->pdev, 0);
>         if ((flags & IORESOURCE_UNSET) || !(flags & IORESOURCE_MEM))
>                 return -EINVAL;
> --
> 2.43.0
>