tests/qtest/vhost-user-test: add a test case for memory-backend-shm

`memory-backend-shm` can be used with vhost-user devices, so let's
add a new test case for it.

Acked-by: Thomas Huth <thuth@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20240618100534.145917-1-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

tests/qtest/vhost-user-test.c

@@ -44,6 +44,8 @@
                         "mem-path=%s,share=on -numa node,memdev=mem"
 #define QEMU_CMD_MEMFD  " -m %d -object memory-backend-memfd,id=mem,size=%dM," \
                         " -numa node,memdev=mem"
+#define QEMU_CMD_SHM    " -m %d -object memory-backend-shm,id=mem,size=%dM," \
+                        " -numa node,memdev=mem"
 #define QEMU_CMD_CHR    " -chardev socket,id=%s,path=%s%s"
 #define QEMU_CMD_NETDEV " -netdev vhost-user,id=hs0,chardev=%s,vhostforce=on"
 
@@ -195,6 +197,7 @@ enum test_memfd {
     TEST_MEMFD_AUTO,
     TEST_MEMFD_YES,
     TEST_MEMFD_NO,
+    TEST_MEMFD_SHM,
 };
 
 static void append_vhost_net_opts(TestServer *s, GString *cmd_line,
@@ -228,6 +231,8 @@ static void append_mem_opts(TestServer *server, GString *cmd_line,
 
     if (memfd == TEST_MEMFD_YES) {
         g_string_append_printf(cmd_line, QEMU_CMD_MEMFD, size, size);
+    } else if (memfd == TEST_MEMFD_SHM) {
+        g_string_append_printf(cmd_line, QEMU_CMD_SHM, size, size);
     } else {
         const char *root = init_hugepagefs() ? : server->tmpfs;
 
@@ -791,6 +796,19 @@ static void *vhost_user_test_setup_memfd(GString *cmd_line, void *arg)
     return server;
 }
 
+static void *vhost_user_test_setup_shm(GString *cmd_line, void *arg)
+{
+    TestServer *server = test_server_new("vhost-user-test", arg);
+    test_server_listen(server);
+
+    append_mem_opts(server, cmd_line, 256, TEST_MEMFD_SHM);
+    server->vu_ops->append_opts(server, cmd_line, "");
+
+    g_test_queue_destroy(vhost_user_test_cleanup, server);
+
+    return server;
+}
+
 static void test_read_guest_mem(void *obj, void *arg, QGuestAllocator *alloc)
 {
     TestServer *server = arg;
@@ -1084,6 +1102,11 @@ static void register_vhost_user_test(void)
                  "virtio-net",
                  test_read_guest_mem, &opts);
 
+    opts.before = vhost_user_test_setup_shm;
+    qos_add_test("vhost-user/read-guest-mem/shm",
+                 "virtio-net",
+                 test_read_guest_mem, &opts);
+
     if (qemu_memfd_check(MFD_ALLOW_SEALING)) {
         opts.before = vhost_user_test_setup_memfd;
         qos_add_test("vhost-user/read-guest-mem/memfd",