Bug 53641

Summary:	nVMX: Windows as L2 guest doesn't work
Product:	Virtualization	Reporter:	Nadav Har'El (nyh)
Component:	kvm	Assignee:	virtualization_kvm
Status:	NEW ---
Severity:	normal	CC:	bornlibra23, szg00000
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:		Subsystem:
Regression:	No	Bisected commit-id:
Bug Depends on:
Bug Blocks:	94971, 53601

Description Nadav Har'El 2013-02-11 14:47:48 UTC

While Linux works fine as nested guests (L2), Windows of various versions do not - which is of course a serious downside of KVM's nested VMX.

I verified this myself - seeing Windows 2000 hang on boot. It was also reported by others and is not specific to Windows 2000, e.g. the following reports by Gianluca Cecchi:

http://lists.fedoraproject.org/pipermail/virt/2011-June/002702.html
http://lists.fedoraproject.org/pipermail/virt/2011-November/002959.html
http://comments.gmane.org/gmane.comp.emulators.kvm.devel/82131

At some point during our research prototype, Windows L2 guests *did* work (including Windows 2000), so it's probably not a big problem, but rather some sneaky bug.

Comment 1 bornlibra23 2013-08-30 23:11:40 UTC

Working on this bug while doing comparative analysis of Linux vs Windows as L2 guest I realized that by forcing addition of PAE & MCA flags in Xen configuration file I saw the boot animation which was previously not being displayed.