Commit f1c1da2b authored by Jan Kiszka's avatar Jan Kiszka Committed by Avi Kivity

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: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 7697e71f
...@@ -1084,7 +1084,6 @@ static void init_vmcb(struct vcpu_svm *svm) ...@@ -1084,7 +1084,6 @@ static void init_vmcb(struct vcpu_svm *svm)
if (npt_enabled) { if (npt_enabled) {
/* Setup VMCB for Nested Paging */ /* Setup VMCB for Nested Paging */
control->nested_ctl = 1; control->nested_ctl = 1;
clr_intercept(svm, INTERCEPT_TASK_SWITCH);
clr_intercept(svm, INTERCEPT_INVLPG); clr_intercept(svm, INTERCEPT_INVLPG);
clr_exception_intercept(svm, PF_VECTOR); clr_exception_intercept(svm, PF_VECTOR);
clr_cr_intercept(svm, INTERCEPT_CR3_READ); clr_cr_intercept(svm, INTERCEPT_CR3_READ);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment