Re: [PATCH v7 6/8] tests/qtest: Add GET_SHMEM validation test

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Mon, Aug 18, 2025 at 12:03:51PM +0200, Albert Esteve wrote:
> Improve vhost-user-test to properly validate
> VHOST_USER_GET_SHMEM_CONFIG message handling by
> directly simulating the message exchange.
> 
> The test manually triggers the
> VHOST_USER_GET_SHMEM_CONFIG message by calling
> chr_read() with a crafted VhostUserMsg, allowing direct
> validation of the shmem configuration response handler.

It looks like this test case invokes its own chr_read() function without
going through QEMU, so I don't understand what this is testing?

> 
> Added TestServerShmem structure to track shmem
> configuration state, including nregions_sent and
> sizes_sent arrays for comprehensive validation.
> The test verifies that the response contains the expected
> number of shared memory regions and their corresponding
> sizes.
> 
> Signed-off-by: Albert Esteve <aesteve@redhat.com>
> ---
>  tests/qtest/vhost-user-test.c | 91 +++++++++++++++++++++++++++++++++++
>  1 file changed, 91 insertions(+)
> 
> diff --git a/tests/qtest/vhost-user-test.c b/tests/qtest/vhost-user-test.c
> index 75cb3e44b2..44a5e90b2e 100644
> --- a/tests/qtest/vhost-user-test.c
> +++ b/tests/qtest/vhost-user-test.c
> @@ -88,6 +88,7 @@ typedef enum VhostUserRequest {
>      VHOST_USER_SET_VRING_ENABLE = 18,
>      VHOST_USER_GET_CONFIG = 24,
>      VHOST_USER_SET_CONFIG = 25,
> +    VHOST_USER_GET_SHMEM_CONFIG = 44,
>      VHOST_USER_MAX
>  } VhostUserRequest;
>  
> @@ -109,6 +110,20 @@ typedef struct VhostUserLog {
>      uint64_t mmap_offset;
>  } VhostUserLog;
>  
> +#define VIRTIO_MAX_SHMEM_REGIONS 256
> +
> +typedef struct VhostUserShMemConfig {
> +    uint32_t nregions;
> +    uint32_t padding;
> +    uint64_t memory_sizes[VIRTIO_MAX_SHMEM_REGIONS];
> +} VhostUserShMemConfig;
> +
> +typedef struct TestServerShmem {
> +    bool test_enabled;
> +    uint32_t nregions_sent;
> +    uint64_t sizes_sent[VIRTIO_MAX_SHMEM_REGIONS];
> +} TestServerShmem;
> +
>  typedef struct VhostUserMsg {
>      VhostUserRequest request;
>  
> @@ -124,6 +139,7 @@ typedef struct VhostUserMsg {
>          struct vhost_vring_addr addr;
>          VhostUserMemory memory;
>          VhostUserLog log;
> +        VhostUserShMemConfig shmem;
>      } payload;
>  } QEMU_PACKED VhostUserMsg;
>  
> @@ -170,6 +186,7 @@ typedef struct TestServer {
>      bool test_fail;
>      int test_flags;
>      int queues;
> +    TestServerShmem shmem;
>      struct vhost_user_ops *vu_ops;
>  } TestServer;
>  
> @@ -513,6 +530,31 @@ static void chr_read(void *opaque, const uint8_t *buf, int size)
>          qos_printf("set_vring(%d)=%s\n", msg.payload.state.index,
>                     msg.payload.state.num ? "enabled" : "disabled");
>          break;
> +    
> +    case VHOST_USER_GET_SHMEM_CONFIG:
> +        if (!s->shmem.test_enabled) {
> +            /* Reply with error if shmem feature not enabled */
> +            msg.flags |= VHOST_USER_REPLY_MASK;
> +            msg.size = sizeof(uint64_t);
> +            msg.payload.u64 = -1; /* Error */
> +            qemu_chr_fe_write_all(chr, (uint8_t *) &msg, VHOST_USER_HDR_SIZE + msg.size);
> +        } else {
> +            /* Reply with test shmem configuration */
> +            msg.flags |= VHOST_USER_REPLY_MASK;
> +            msg.size = sizeof(VhostUserShMemConfig);
> +            msg.payload.shmem.nregions = 2; /* Test with 2 regions */
> +            msg.payload.shmem.padding = 0;
> +            msg.payload.shmem.memory_sizes[0] = 0x100000; /* 1MB */
> +            msg.payload.shmem.memory_sizes[1] = 0x200000; /* 2MB */
> +            
> +            /* Record what we're sending for test validation */
> +            s->shmem.nregions_sent = msg.payload.shmem.nregions;
> +            s->shmem.sizes_sent[0] = msg.payload.shmem.memory_sizes[0];
> +            s->shmem.sizes_sent[1] = msg.payload.shmem.memory_sizes[1];
> +            
> +            qemu_chr_fe_write_all(chr, (uint8_t *) &msg, VHOST_USER_HDR_SIZE + msg.size);
> +        }
> +        break;
>  
>      default:
>          qos_printf("vhost-user: un-handled message: %d\n", msg.request);
> @@ -809,6 +851,22 @@ static void *vhost_user_test_setup_shm(GString *cmd_line, void *arg)
>      return server;
>  }
>  
> +static void *vhost_user_test_setup_shmem_config(GString *cmd_line, void *arg)
> +{
> +    TestServer *server = test_server_new("vhost-user-test", arg);
> +    test_server_listen(server);
> +
> +    /* Enable shmem testing for this server */
> +    server->shmem.test_enabled = true;
> +
> +    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;
> @@ -1089,6 +1147,33 @@ static struct vhost_user_ops g_vu_net_ops = {
>      .get_protocol_features = vu_net_get_protocol_features,
>  };
>  
> +/* Test function for VHOST_USER_GET_SHMEM_CONFIG message */
> +static void test_shmem_config(void *obj, void *arg, QGuestAllocator *alloc)
> +{
> +    TestServer *s = arg;
> +    
> +    g_assert_true(s->shmem.test_enabled);
> +    
> +    g_mutex_lock(&s->data_mutex);
> +    s->shmem.nregions_sent = 0;
> +    s->shmem.sizes_sent[0] = 0;
> +    s->shmem.sizes_sent[1] = 0;
> +    g_mutex_unlock(&s->data_mutex);
> +    
> +    VhostUserMsg msg = {
> +        .request = VHOST_USER_GET_SHMEM_CONFIG,
> +        .flags = VHOST_USER_VERSION,
> +        .size = 0,
> +    };
> +    chr_read(s, (uint8_t *) &msg, VHOST_USER_HDR_SIZE);
> +
> +    g_mutex_lock(&s->data_mutex);
> +    g_assert_cmpint(s->shmem.nregions_sent, ==, 2);
> +    g_assert_cmpint(s->shmem.sizes_sent[0], ==, 0x100000); /* 1MB */
> +    g_assert_cmpint(s->shmem.sizes_sent[1], ==, 0x200000); /* 2MB */
> +    g_mutex_unlock(&s->data_mutex);
> +}
> +
>  static void register_vhost_user_test(void)
>  {
>      QOSGraphTestOptions opts = {
> @@ -1136,6 +1221,12 @@ static void register_vhost_user_test(void)
>      qos_add_test("vhost-user/multiqueue",
>                   "virtio-net",
>                   test_multiqueue, &opts);
> +    
> +    opts.before = vhost_user_test_setup_shmem_config;
> +    opts.edge.extra_device_opts = "";
> +    qos_add_test("vhost-user/shmem-config",
> +                 "virtio-net",
> +                 test_shmem_config, &opts);
>  }
>  libqos_init(register_vhost_user_test);
>  
> -- 
> 2.49.0
> 

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