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: 89c8a498 ("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>
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