libxl: Probe QEMU for -run-with user=user and use it

"-runas" is deprecated since QEMU 9.1 and will be remove in a future
release.

Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>

tools/libs/light/libxl_dm.c

@@ -2052,10 +2052,15 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
         }
 
         if (state->dm_runas) {
+            if (qemu_opts->have_runwith_user) {
+                flexarray_append_pair(dm_args, "-run-with",
+                                      GCSPRINTF("user=%s", state->dm_runas));
+            } else {
                 flexarray_append(dm_args, "-runas");
                 flexarray_append(dm_args, state->dm_runas);
             }
         }
+    }
     flexarray_append(dm_args, NULL);
     *args = (char **) flexarray_contents(dm_args);
     flexarray_append(dm_envs, NULL);
@@ -3073,6 +3078,9 @@ static void device_model_probe_cmdline(libxl__egc *egc,
                 if (!strcmp("chroot", libxl__json_object_get_string(o))) {
                     dmss->qemu_opts.have_runwith_chroot = true;
                 }
+                else if (!strcmp("user", libxl__json_object_get_string(o))) {
+                    dmss->qemu_opts.have_runwith_user = true;
+                }
             }
 
             /*

tools/libs/light/libxl_internal.h

@@ -4145,6 +4145,7 @@ typedef struct libxl__dm_spawn_state libxl__dm_spawn_state;
 typedef struct libxl__qemu_available_opts libxl__qemu_available_opts;
 struct libxl__qemu_available_opts {
     bool have_runwith_chroot;
+    bool have_runwith_user;
 };
 
 typedef void libxl__dm_spawn_cb(libxl__egc *egc, libxl__dm_spawn_state*,