hw/xen: add stubs for various functions

Those symbols are used by system/physmem.c, and are called only if
xen_enabled() (which happens only if CONFIG_XEN is set and xen is
available).

So we can crash the stubs in case those are called, as they are linked
only when CONFIG_XEN is not set.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250317183417.285700-13-pierrick.bouvier@linaro.org>

2 files changed, 54 insertions, 0 deletions

diff --git a/hw/xen/meson.build b/hw/xen/meson.build
index 4a486e3673..a1850e7698 100644
--- a/hw/xen/meson.build
+++ b/hw/xen/meson.build
@@ -9,6 +9,9 @@ system_ss.add(when: ['CONFIG_XEN_BUS'], if_true: files(
 
 system_ss.add(when: ['CONFIG_XEN', xen], if_true: files(
   'xen-operations.c',
+),
+if_false: files(
+  'xen_stubs.c',
 ))
 
 xen_specific_ss = ss.source_set()
diff --git a/hw/xen/xen_stubs.c b/hw/xen/xen_stubs.c
new file mode 100644
index 0000000000..5e565df392
--- /dev/null
+++ b/hw/xen/xen_stubs.c
@@ -0,0 +1,51 @@
+/*
+ * Various stubs for xen functions
+ *
+ * Those functions are used only if xen_enabled(). This file is linked only if
+ * CONFIG_XEN is not set, so they should never be called.
+ *
+ * Copyright (c) 2025 Linaro, Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "system/xen.h"
+#include "system/xen-mapcache.h"
+
+void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length)
+{
+    g_assert_not_reached();
+}
+
+void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
+                   struct MemoryRegion *mr, Error **errp)
+{
+    g_assert_not_reached();
+}
+
+bool xen_mr_is_memory(MemoryRegion *mr)
+{
+    g_assert_not_reached();
+}
+
+void xen_invalidate_map_cache_entry(uint8_t *buffer)
+{
+    g_assert_not_reached();
+}
+
+ram_addr_t xen_ram_addr_from_mapcache(void *ptr)
+{
+    g_assert_not_reached();
+}
+
+uint8_t *xen_map_cache(MemoryRegion *mr,
+                       hwaddr phys_addr,
+                       hwaddr size,
+                       ram_addr_t ram_addr_offset,
+                       uint8_t lock,
+                       bool dma,
+                       bool is_write)
+{
+    g_assert_not_reached();
+}