[Intel-gfx] [PATCH v3 3/8] drm/i915: Partition the fence registers for vGPU in i915 driver

[Tvrtko Ursulin]

Hi,

On 12/16/2014 02:41 PM, Gerd Hoffmann wrote:
>> I didn't figure out how each domain knowns which fences to use? They
>> know how many, but which ones?
>
> I think the guest doesn't have to know because mmio access is trapped by
> the hypervisor anyway.

Okay.. so the point is to ensure no domain can hog all fences, but if 
the hypervisor is already tracking everything why is this limiting 
required then in the guest? Hypervisor could just say all fences are 
allocated since it knows how much it gave out per guest.

Regards,

Tvrtko