On Tue, Oct 18, 2011 at 12:23:11PM -0400, Jan Kiszka wrote: > 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 <[email protected]>
Acked-by: Joerg Roedel <[email protected]> > --- > arch/x86/kvm/svm.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index e7ed4b1..e32243e 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -1084,7 +1084,6 @@ static void init_vmcb(struct vcpu_svm *svm) > if (npt_enabled) { > /* Setup VMCB for Nested Paging */ > control->nested_ctl = 1; > - clr_intercept(svm, INTERCEPT_TASK_SWITCH); > clr_intercept(svm, INTERCEPT_INVLPG); > clr_exception_intercept(svm, PF_VECTOR); > clr_cr_intercept(svm, INTERCEPT_CR3_READ); > -- > 1.7.3.4 -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
