KVM: nVMX: Fail VMLAUNCH and VMRESUME on shadow VMCS

Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 44e2b82f65198ef925df1c1985b7e53b4d3e291c..f6ec898ac53981ab3df8612bb8ad3e66abe84df6 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11876,6 +11876,17 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 
        vmcs12 = get_vmcs12(vcpu);
 
+       /*
+        * Can't VMLAUNCH or VMRESUME a shadow VMCS. Despite the fact
+        * that there *is* a valid VMCS pointer, RFLAGS.CF is set
+        * rather than RFLAGS.ZF, and no error number is stored to the
+        * VM-instruction error field.
+        */
+       if (vmcs12->hdr.shadow_vmcs) {
+               nested_vmx_failInvalid(vcpu);
+               goto out;
+       }
+
        if (enable_shadow_vmcs)
                copy_shadow_to_vmcs12(vmx);