diff options
| author | Maxim Levitsky <mlevitsk@redhat.com> | 2021-07-19 16:05:00 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-08-18 08:57:04 +0200 |
| commit | a17f2f2c89494c0974529579f3552ecbd1bc2d52 (patch) | |
| tree | e481e08a2f3a7f517ad53e3ed8726438bf3e7939 | |
| parent | 7c1c96ffb658fbfe66c5ebed6bcb5909837bc267 (diff) | |
KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656)
commit c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kvm/svm.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 07a52f1bebe0..425444d08071 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -516,6 +516,9 @@ static void recalc_intercepts(struct vcpu_svm *svm) c->intercept_dr = h->intercept_dr | g->intercept_dr; c->intercept_exceptions = h->intercept_exceptions | g->intercept_exceptions; c->intercept = h->intercept | g->intercept; + + c->intercept |= (1ULL << INTERCEPT_VMLOAD); + c->intercept |= (1ULL << INTERCEPT_VMSAVE); } static inline struct vmcb *get_host_vmcb(struct vcpu_svm *svm) |