KVM: nVMX: do not leak PML full vmexit to L1

BugLink: http://bugs.launchpad.net/bugs/1691418

commit ab007cc9 upstream.

The PML feature is not exposed to guests so we should not be forwarding
the vmexit either.

This commit fixes BSOD 0x20001 (HYPERVISOR_ERROR) when running Hyper-V
enabled Windows Server 2016 in L1 on hardware that supports PML.

Fixes: 843e4330 ("KVM: VMX: Add PML support in VMX")
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

arch/x86/kvm/vmx.c

@@ -7842,6 +7842,9 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has2(vmcs12, SECONDARY_EXEC_XSAVES);
 	case EXIT_REASON_PCOMMIT:
 		return nested_cpu_has2(vmcs12, SECONDARY_EXEC_PCOMMIT);
+	case EXIT_REASON_PML_FULL:
+		/* We don't expose PML support to L1. */
+		return false;
 	default:
 		return true;
 	}