modules: check arch and block load on mismatch

Add module_allow_arch() to set the target architecture.
In case a module is limited to some arch verify arches
match and ignore the module if not.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jose R. Ziviani <jziviani@suse.de>
Message-Id: <20210624103836.2382472-19-kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/qemu/module.h

@@ -72,6 +72,7 @@ void module_call_init(module_init_type type);
 bool module_load_one(const char *prefix, const char *lib_name, bool mayfail);
 void module_load_qom_one(const char *type);
 void module_load_qom_all(void);
+void module_allow_arch(const char *arch);
 
 /**
  * DOC: module info annotation macros

softmmu/vl.c

@@ -126,6 +126,8 @@
 #include "sysemu/iothread.h"
 #include "qemu/guest-random.h"
 
+#include "config-host.h"
+
 #define MAX_VIRTIO_CONSOLES 1
 
 typedef struct BlockdevOptionsQueueEntry {
@@ -2740,6 +2742,7 @@ void qemu_init(int argc, char **argv, char **envp)
 
 #ifdef CONFIG_MODULES
     module_init_info(qemu_modinfo);
+    module_allow_arch(TARGET_NAME);
 #endif
 
     qemu_init_subsystems();

util/module.c

@@ -117,12 +117,33 @@ static const QemuModinfo module_info_stub[] = { {
     /* end of list */
 } };
 static const QemuModinfo *module_info = module_info_stub;
+static const char *module_arch;
 
 void module_init_info(const QemuModinfo *info)
 {
     module_info = info;
 }
 
+void module_allow_arch(const char *arch)
+{
+    module_arch = arch;
+}
+
+static bool module_check_arch(const QemuModinfo *modinfo)
+{
+    if (modinfo->arch) {
+        if (!module_arch) {
+            /* no arch set -> ignore all */
+            return false;
+        }
+        if (strcmp(module_arch, modinfo->arch) != 0) {
+            /* mismatch */
+            return false;
+        }
+    }
+    return true;
+}
+
 static int module_load_file(const char *fname, bool mayfail, bool export_symbols)
 {
     GModule *g_module;
@@ -224,6 +245,13 @@ bool module_load_one(const char *prefix, const char *lib_name, bool mayfail)
     g_hash_table_add(loaded_modules, module_name);
 
     for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
+        if (modinfo->arch) {
+            if (strcmp(modinfo->name, module_name) == 0) {
+                if (!module_check_arch(modinfo)) {
+                    return false;
+                }
+            }
+        }
         if (modinfo->deps) {
             if (strcmp(modinfo->name, module_name) == 0) {
                 /* we depend on other module(s) */
@@ -345,6 +373,7 @@ void qemu_load_module_for_opts(const char *group)
 
 #else
 
+void module_allow_arch(const char *arch) {}
 void qemu_load_module_for_opts(const char *group) {}
 void module_load_qom_one(const char *type) {}
 void module_load_qom_all(void) {}