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| author | Maxim Levitsky <mlevitsk@redhat.com> | 2021-07-19 16:05:00 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-08-16 09:48:37 -0400 |
| commit | c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc (patch) | |
| tree | 42c6b74cec101cdffce4c14e608b4c672adb4b61 | |
| parent | 0f923e07124df069ba68d8bb12324398f4b6b709 (diff) | |
KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656)
If L1 disables VMLOAD/VMSAVE intercepts, and doesn't enable
Virtual VMLOAD/VMSAVE (currently not supported for the nested hypervisor),
then VMLOAD/VMSAVE must operate on the L1 physical memory, which is only
possible by making L0 intercept these instructions.
Failure to do so allowed the nested guest to run VMLOAD/VMSAVE unintercepted,
and thus read/write portions of the host physical memory.
Fixes: 89c8a4984fc9 ("KVM: SVM: Enable Virtual VMLOAD VMSAVE feature")
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/svm/nested.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 28381ca5221c..e5515477c30a 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -158,6 +158,9 @@ void recalc_intercepts(struct vcpu_svm *svm) /* If SMI is not intercepted, ignore guest SMI intercept as well */ if (!intercept_smi) vmcb_clr_intercept(c, INTERCEPT_SMI); + + vmcb_set_intercept(c, INTERCEPT_VMLOAD); + vmcb_set_intercept(c, INTERCEPT_VMSAVE); } static void copy_vmcb_control_area(struct vmcb_control_area *dst, |