KVM: nVMX: fix instruction skipping during emulated vm-entry

kvm_skip_emulated_instruction() should not be called after emulating
a VM-entry failure during or after loading guest state
(nested_vmx_entry_failure()). Otherwise the L1 hypervisor is resumed
some number of bytes past vmcs->host_rip.

Fixes: eb2775621701e6ee3ea2a474437d04e93ccdcb2f
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -10473,12 +10473,12 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	    !nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4)) {
 		nested_vmx_entry_failure(vcpu, vmcs12,
 			EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
-		goto out;
+		return 1;
 	}
 	if (vmcs12->vmcs_link_pointer != -1ull) {
 		nested_vmx_entry_failure(vcpu, vmcs12,
 			EXIT_REASON_INVALID_STATE, ENTRY_FAIL_VMCS_LINK_PTR);
-		goto out;
+		return 1;
 	}
 
 	/*
@@ -10498,7 +10498,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 		     ia32e != !!(vmcs12->guest_ia32_efer & EFER_LME))) {
 			nested_vmx_entry_failure(vcpu, vmcs12,
 				EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
-			goto out;
+			return 1;
 		}
 	}
 
@@ -10516,7 +10516,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 		    ia32e != !!(vmcs12->host_ia32_efer & EFER_LME)) {
 			nested_vmx_entry_failure(vcpu, vmcs12,
 				EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
-			goto out;
+			return 1;
 		}
 	}