KVM: SVM: Keep intercepting task switching with NPT enabled
authorJan Kiszka <jan.kiszka@siemens.com>
Tue, 18 Oct 2011 16:23:11 +0000 (18:23 +0200)
committerAvi Kivity <avi@redhat.com>
Sun, 30 Oct 2011 10:24:10 +0000 (12:24 +0200)
commitf1c1da2bde712812a3e0f9a7a7ebe7a916a4b5f4
treedb3715f38fd012cece847d0f0918cbc12eb2123f
parent7697e71f72b45a1bd0abe70918c383100fcc8514
KVM: SVM: Keep intercepting task switching with NPT enabled

AMD processors apparently have a bug in the hardware task switching
support when NPT is enabled. If the task switch triggers a NPF, we can
get wrong EXITINTINFO along with that fault. On resume, spurious
exceptions may then be injected into the guest.

We were able to reproduce this bug when our guest triggered #SS and the
handler were supposed to run over a separate task with not yet touched
stack pages.

Work around the issue by continuing to emulate task switches even in
NPT mode.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
arch/x86/kvm/svm.c