[Intel-gfx] [FW: [PATCH 3/6] drm/i915/gtt: Disable read-only support under GVT]

[Yuan, Hang]

> -----Original Message-----
> From: intel-gvt-dev [mailto:intel-gvt-dev-bounces at lists.freedesktop.org] On
> Behalf Of Chris Wilson
> Sent: Thursday, October 25, 2018 8:51 PM
> To: Yuan, Hang <hang.yuan at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; joonas.lahtinen at linux.intel.com;
> matthew.william.auld at gmail.com; Zhenyu Wang
> <zhenyuw at linux.intel.com>; Bloomfield, Jon <jon.bloomfield at intel.com>;
> intel-gvt-dev at lists.freedesktop.org
> Subject: RE: [FW: [PATCH 3/6] drm/i915/gtt: Disable read-only support under
> GVT]
> 
> Quoting Yuan, Hang (2018-10-25 11:07:48)
> > Hi Chris,
> >
> > I checked GVT shadow PPGTT handling codes and think GVT does
> propagate guest PTE flags to shadow PPGTT entry. Then I run i915 self-test
> case "igt_ctx_readonly" in KVMGT's guest. The case doesn't report any errors.
> Can I know if there are any other reasons that you think GVT breaks read-
> only support?
> 
> I thought it was from a ci result, but going back through the logs we have
> never run the selftests at that time under CI. So call it a lack of testing and a
> misread of the code.
> 
> igt_ctx_readonly should be sufficient to prove the test, except it needs a bit
> of refinement to be stricter over hang detection.
> https://patchwork.freedesktop.org/patch/256433/
> -Chris
[Yuan, Hang] Thanks. I will apply the patch and test again.