Re: [PATCH 6/6] tests/qtest: migration-test: Add tests for file-based migration

[Peter Xu]

On Wed, Jun 28, 2023 at 01:55:42PM -0300, Fabiano Rosas wrote:
> Add basic tests for file-based migration.
> 
> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> ---
>  tests/qtest/migration-test.c | 104 +++++++++++++++++++++++++++++++++++
>  1 file changed, 104 insertions(+)
> 
> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> index acb778a8cd..b3019f54de 100644
> --- a/tests/qtest/migration-test.c
> +++ b/tests/qtest/migration-test.c
> @@ -52,6 +52,10 @@ static bool got_dst_resume;
>   */
>  #define DIRTYLIMIT_TOLERANCE_RANGE  25  /* MB/s */
>  
> +#define QEMU_VM_FILE_MAGIC 0x5145564d
> +#define FILE_TEST_FILENAME "migfile"
> +#define FILE_TEST_OFFSET 0x1000
> +
>  #if defined(__linux__)
>  #include <sys/syscall.h>
>  #include <sys/vfs.h>
> @@ -763,6 +767,7 @@ static void test_migrate_end(QTestState *from, QTestState 
> *to, bool test_dest)
>      cleanup("migsocket");
>      cleanup("src_serial");
>      cleanup("dest_serial");
> +    cleanup(FILE_TEST_FILENAME);
>  }
>  
>  #ifdef CONFIG_GNUTLS
> @@ -1460,11 +1465,28 @@ static void test_precopy_common(MigrateCommon *args)
>               */
>              wait_for_migration_complete(from);
>  
> +            /*
> +             * For file based migration the target must begin its
> +             * migration after the source has finished.
> +             */
> +            if (strstr(connect_uri, "file:")) {
> +                migrate_incoming_qmp(to, connect_uri, "{}");
> +            }
> +
>              if (!got_src_stop) {
>                  qtest_qmp_eventwait(from, "STOP");
>              }
>          } else {
>              wait_for_migration_complete(from);
> +
> +            /*
> +             * For file based migration the target must begin its
> +             * migration after the source has finished.
> +             */
> +            if (strstr(connect_uri, "file:")) {
> +                migrate_incoming_qmp(to, connect_uri, "{}");
> +            }
> +
>              /*
>               * Must wait for dst to finish reading all incoming
>               * data on the socket before issuing 'cont' otherwise
> @@ -1682,6 +1704,78 @@ static void test_precopy_unix_compress_nowait(void)
>      test_precopy_common(&args);
>  }
>  
> +static void test_precopy_file(void)
> +{
> +    g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
> +                                           FILE_TEST_FILENAME);
> +    MigrateCommon args = {
> +        .connect_uri = uri,
> +        .listen_uri = "defer",
> +    };
> +
> +    test_precopy_common(&args);
> +}
> +
> +#if defined(__linux__)
> +static void file_offset_finish_hook(QTestState *from, QTestState *to, void 
> *opaque)
> +{
> +    g_autofree char *path = g_strdup_printf("%s/%s", tmpfs, 
> FILE_TEST_FILENAME);
> +    size_t size = FILE_TEST_OFFSET + sizeof(QEMU_VM_FILE_MAGIC);
> +    uintptr_t *addr, *p;
> +    int fd;
> +
> +    fd = open(path, O_RDONLY);
> +    g_assert(fd != -1);
> +    addr = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);

Not something that matters a lot, but RO mapping a file with private is a
bit weird.  Maybe just use MAP_SHARED?

> +    g_assert(addr != MAP_FAILED);
> +
> +    /*
> +     * Ensure the skipped offset contains zeros and the migration
> +     * stream starts at the right place.
> +     */
> +    p = addr;
> +    while (p < addr + FILE_TEST_OFFSET / sizeof(uintptr_t)) {
> +        g_assert(*p == 0);
> +        p++;
> +    }
> +    g_assert_cmpint(cpu_to_be32(*p), ==, QEMU_VM_FILE_MAGIC);
> +
> +    munmap(addr, size);
> +    close(fd);
> +}
> +
> +static void test_precopy_file_offset(void)
> +{
> +    g_autofree char *uri = g_strdup_printf("file:%s/%s,offset=%d", tmpfs,
> +                                           FILE_TEST_FILENAME,
> +                                           FILE_TEST_OFFSET);

Is it intended to also only run this test with linux?  IIUC it should also
work for others. Maybe only file_offset_finish_hook() is optional?  Or am i
wrong?

> +    MigrateCommon args = {
> +        .connect_uri = uri,
> +        .listen_uri = "defer",
> +        .finish_hook = file_offset_finish_hook,
> +    };
> +
> +    test_precopy_common(&args);
> +}
> +#endif
> +
> +static void test_precopy_file_offset_bad(void)
> +{
> +    /* using a value not supported by qemu_strtosz() */
> +    g_autofree char *uri = g_strdup_printf("file:%s/migfile,offset=0x20M",
> +                                           tmpfs);
> +    MigrateCommon args = {
> +        .connect_uri = uri,
> +        .listen_uri = "defer",
> +        .error_str = g_strdup(
> +            "file URI has bad offset 0x20M: Unknown error -22"),

"Unknown error" may imply that in Steve's patch the errno is inverted..

Shall we not rely on the string in the test?  It might be too strict, I
worry, because error strings should be defined for human readers, and we
may not want some e.g. grammar / trivial change to break a test.

> +        .result = MIG_TEST_QMP_ERROR,
> +    };
> +
> +    test_precopy_common(&args);
> +    g_free(args.error_str);
> +}
> +
>  static void test_precopy_tcp_plain(void)
>  {
>      MigrateCommon args = {
> @@ -2704,6 +2798,16 @@ int main(int argc, char **argv)
>          qtest_add_func("/migration/precopy/unix/compress/nowait",
>                         test_precopy_unix_compress_nowait);
>      }
> +
> +    qtest_add_func("/migration/precopy/file",
> +                   test_precopy_file);
> +#if defined(__linux__)
> +    qtest_add_func("/migration/precopy/file/offset",
> +                   test_precopy_file_offset);
> +#endif
> +    qtest_add_func("/migration/precopy/file/offset/bad",
> +                   test_precopy_file_offset_bad);
> +
>  #ifdef CONFIG_GNUTLS
>      qtest_add_func("/migration/precopy/unix/tls/psk",
>                     test_precopy_unix_tls_psk);
> -- 
> 2.35.3
> 

-- 
Peter Xu