[Intel-gfx] [RFCv2 10/14] drm/i915: update PDPs by condition when submit the LRC context

[Tian, Kevin]

> From: Wang, Zhi A
> Sent: Thursday, February 18, 2016 7:42 PM
> 
> Previously the PDPs inside the ring context are updated at:
> 
> - When populate a LRC context
> - Before submitting a LRC context (only for 32 bit PPGTT, as the amount
> of used PDPs may change)
> 
> This patch postpones the PDPs upgrade to submission time, and will update
> it by condition if the PPGTT is 48b. Under GVT-g, one GVT context will be
> used by different guest, the PPGTT instance related to the context might
> be changed before the submission time. And this patch gives GVT context
> a chance to load the new PPGTT instance into an initialized context.

Could you elaborate why we share one GVT context across different guest?
A natural thought is that we'll create one GVT context per every guest
context...

Thanks
Kevin