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authorMaxim Levitsky <mlevitsk@redhat.com>2021-09-14 18:48:14 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2021-09-23 10:05:29 -0400
commitd1cba6c9223751f580dcd97501f513a8a9bf88bc (patch)
tree6c318e8097f35749ce95b53f0a6cdf57bdaae069 /arch
parent1ad32105d78e4b5da60688eca014bcd45271318f (diff)
KVM: x86: nSVM: test eax for 4K alignment for GP errata workaround
GP SVM errata workaround made the #GP handler always emulate the SVM instructions. However these instructions #GP in case the operand is not 4K aligned, but the workaround code didn't check this and we ended up emulating these instructions anyway. This is only an emulation accuracy check bug as there is no harm for KVM to read/write unaligned vmcb images. Fixes: 82a11e9c6fa2 ("KVM: SVM: Add emulation support for #GP triggered by SVM instructions") Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210914154825.104886-4-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/svm/svm.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d674304d45a2..989685098b3e 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2224,6 +2224,10 @@ static int gp_interception(struct kvm_vcpu *vcpu)
if (error_code)
goto reinject;
+ /* All SVM instructions expect page aligned RAX */
+ if (svm->vmcb->save.rax & ~PAGE_MASK)
+ goto reinject;
+
/* Decode the instruction for usage later */
if (x86_decode_emulated_instruction(vcpu, 0, NULL, 0) != EMULATION_OK)
goto reinject;

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