[PATCH] drm/amdgpu/gmc: use PCI BARs for APUs in passthrough

[Michel Dänzer]

On 2022-03-11 11:32, Christian König wrote:
> Am 11.03.22 um 11:24 schrieb Michel Dänzer:
>> On 2022-03-10 19:06, Alex Deucher wrote:
>>> If the GPU is passed through to a guest VM, use the PCI
>>> BAR for CPU FB access rather than the physical address of
>>> carve out.  The physical address is not valid in a guest.
>> I think amdgpu_device_flush_hdp & amdgpu_device_invalidate_hdp need to be modified accordingly.

I'm surprised you gave your R-b despite this. Surely the HDP cache needs to be handled when going through the BAR?


>> Also, I wonder if BAR resizing could work with APUs?
> 
> At least trivial to implement.
> 
> The host had to resize the BAR for the client or otherwise the client could easily bring down the system.

Gotcha, makes sense.


-- 
Earthling Michel Dänzer            |                  https://redhat.com
Libre software enthusiast          |         Mesa and Xwayland developer