Import QEMU upstream snapshot d2e570c

Upstream: https://gitlab.com/qemu-project/qemu.git

Upstream-Commit: d2e570cc0f97b936902a5b1b86b73c0f5998b475

accel/stubs/hvf-stub.c

@@ -0,0 +1,24 @@
+/*
+ * HVF stubs for QEMU
+ *
+ *  Copyright (c) Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "system/hvf.h"
+
+bool hvf_allowed;
+bool hvf_kernel_irqchip;
+bool hvf_nested_virt;
+
+void hvf_nested_virt_enable(bool nested_virt)
+{
+    /*
+     * This is called unconditionally from hw/arm/virt.c
+     * because we don't know if HVF is going to be used
+     * as that step of initialisation happens later.
+     * As such, do nothing here instead of marking as unreachable.
+     */
+}