Bug 110234

Summary:	[Bug] guest i915 may guess the wrong PCH in virtual env
Product:	DRI	Reporter:	XiongZhang <xiong.y.zhang>
Component:	DRM/iGVT-g	Assignee:	Terrence Xu <terrence.xu>
Status:	RESOLVED MOVED	QA Contact:	Terrence Xu <terrence.xu>
Severity:	trivial
Priority:	medium	CC:	intel-gfx-bugs, joonas.lahtinen
Version:	DRI git
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description XiongZhang 2019-03-25 08:45:11 UTC

Currently guest i915 guess pch type according to processor type in virtual env.
As the real pch isn't in guest, but guest i915 need pch for some function, then guest i915 has to guess the pch type. Normally this guess is right, but this guess may be wrong in the following case:
1) ULT/ULX processor with non LP PCH
2) normal processor with LP pch

In order to fix it, the real pch id should be passed to guest, but there isn't a standard way to do this. Hacker method is needed in QEMU and i915, and kinds of hacker are rejected by QEMU.

Comment 1 Joonas Lahtinen 2019-03-29 10:42:35 UTC

This was recognized as a potential issue multiple years ago, but then such strange hardware configurations did not exist even if the potential issue was recognized.

Do you have some specific hardware configuration to specify as an example?

Moving this for the GVT-g team to resolve, as the hypervisor needs to pass the information somehow.

Comment 2 Martin Peres 2019-11-29 16:48:14 UTC

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/drm/intel/issues/14.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.