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| author | Maxim Levitsky <mlevitsk@redhat.com> | 2021-08-16 16:02:37 +0200 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2021-08-26 08:36:42 -0400 |
| commit | 119d547cbf7c055ba8100309ad71910478092f24 (patch) | |
| tree | 1a892db3a4c356b5614a9e272ec66956a02cef8b | |
| parent | 11cad2a46103388a46f31ab69b3e0e152a08df9c (diff) | |
| download | linux-stable-119d547cbf7c055ba8100309ad71910478092f24.tar.gz linux-stable-119d547cbf7c055ba8100309ad71910478092f24.tar.bz2 linux-stable-119d547cbf7c055ba8100309ad71910478092f24.zip | |
KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656)
[ upstream commit c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc ]
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 72d729f34437..9673ddb3d7a0 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -513,6 +513,9 @@ 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) |