[PATCH] iommu/amd: fix the address translation issue when do detach

[Vasant Hegde]

On 7/27/2023 3:25 PM, Jesse Zhang wrote:
> From: Jesse Zhang <jesse.zhang at amd.com>
> 
> iGpu driver fail to read/write register by iommu when start X.
> kernel: [  433.296634] audit: type=1400 audit(1690403823.130:64): apparmor="DENIED" operation="capable" class="cap"
> profile="/snap/snapd/19457/usr/lib/snapd/snap-confine" pid=12344 comm="snap-confine" capability=38  capname="perfmon"
> kernel: [  433.515795] amdgpu 0000:03:00.0: amdgpu: failed to write reg 28b4 wait reg 28c6
> kernel: [  440.195492] amdgpu 0000:03:00.0: amdgpu: failed to write reg 28b4 wait reg 28c6
> kernel: [  453.679611] amdgpu 0000:03:00.0: amdgpu: failed to write reg 1a6f4 wait reg 1a706
> kernel: [  460.383490] amdgpu 0000:03:00.0: amdgpu: failed to write reg 1a6f4 wait reg 1a706
> 
> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2659
> 
> Disable address translation service, before detach device.
> Do detach will clear the page table point or pasid table entries,
> so all DMA requests from the device should be blocked before that.
> 
> Signed-off-by: Jesse Zhang <Jesse.Zhang at amd.com>

Thanks Jesse for tracking down the issue. Patch looks good to me.

Reviewed-by: Vasant Hegde <vasant.hegde at amd.com>

-Vasant