KVM: selftests: nVMX: Properly deal with 'hv_clean_fields'

Instead of just resetting 'hv_clean_fields' to 0 on every enlightened
vmresume, do the expected cleaning of the corresponding bit on enlightened
vmwrite. Avoid direct access to 'current_evmcs' from evmcs_test to support
the change.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220203104620.277031-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/x86_64/evmcs_test.c

@@ -76,8 +76,9 @@ void guest_code(struct vmx_pages *vmx_pages)
 	current_evmcs->revision_id = EVMCS_VERSION;
 	GUEST_SYNC(6);
 
-	current_evmcs->pin_based_vm_exec_control |=
-		PIN_BASED_NMI_EXITING;
+	vmwrite(PIN_BASED_VM_EXEC_CONTROL, vmreadz(PIN_BASED_VM_EXEC_CONTROL) |
+		PIN_BASED_NMI_EXITING);
+
 	GUEST_ASSERT(!vmlaunch());
 	GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);