[PATCH 4/4] nvmx: check for shadow vmcs check on entry

[Bandan Das <bsd@redhat.com>]

vmentry should check whether the vmcs provided by
the guest hypervisor is a shadow vmcs and fail.
Also, vmptrld should check whether a shadow vmcs
is being loaded by the guest without support being present
but this check happens as part of checking the revision_id.

Signed-off-by: Bandan Das <bsd@redhat.com>
---
 arch/x86/kvm/vmx.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6291143..1b6f624 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9924,6 +9924,10 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 
 	skip_emulated_instruction(vcpu);
 	vmcs12 = get_vmcs12(vcpu);
+	if ((vmcs12->revision_id >> 31) & 1u) {
+		nested_vmx_failInvalid(vcpu);
+		return 1;
+	}
 
 	if (enable_shadow_vmcs)
 		copy_shadow_to_vmcs12(vmx);
-- 
2.5.5