Re: [PULL 11/38] tests/qtest: migration-test: Add tests for file-based migration

[Juan Quintela <quintela@redhat.com>]

Fabiano Rosas <farosas@suse.de> wrote:
D> Juan Quintela <quintela@redhat.com> writes:
>
>> From: Fabiano Rosas <farosas@suse.de>
>>
>> Add basic tests for file-based migration.
>>
>> Note that we cannot use test_precopy_common because that routine
>> expects it to be possible to run the migration live. With the file
>> transport there is no live migration because we must wait for the
>> source to finish writing the migration data to the file before the
>> destination can start reading. Add a new migration function
>> specifically to handle the file migration.
>>
>> Reviewed-by: Peter Xu <peterx@redhat.com>
>> Reviewed-by: Juan Quintela <quintela@redhat.com>
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> Signed-off-by: Juan Quintela <quintela@redhat.com>
>> Message-ID: <20230712190742.22294-7-farosas@suse.de>

>> +static void file_offset_finish_hook(QTestState *from, QTestState *to,
>> +                                    void *opaque)
>> +{
>> +#if defined(__linux__)
>> +    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_SHARED, fd, 0);
>> +    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);
>
> This truncates to 32-bits, so it breaks on a BE host. We need this:
>
> -->8--
> From ea0c2d1c988add48d9754891a9fc7f6854a9718a Mon Sep 17 00:00:00 2001
> From: Fabiano Rosas <farosas@suse.de>
> Date: Mon, 16 Oct 2023 15:21:49 -0300
> Subject: [PATCH] fixup! tests/qtest: migration-test: Add tests for file-based
>  migration
>
> ---
>  tests/qtest/migration-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> index da02b6d692..e1c110537b 100644
> --- a/tests/qtest/migration-test.c
> +++ b/tests/qtest/migration-test.c
> @@ -1966,7 +1966,7 @@ static void file_offset_finish_hook(QTestState *from, QTestState *to,
>          g_assert(*p == 0);
>          p++;
>      }
> -    g_assert_cmpint(cpu_to_be32(*p), ==, QEMU_VM_FILE_MAGIC);
> +    g_assert_cmpint(cpu_to_be64(*p) >> 32, ==, QEMU_VM_FILE_MAGIC);
>  
>      munmap(addr, size);
>      close(fd);

I am resubmitting with this change.

But I think we need to change this:

>> +    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;

I think we should change the test so the file is 64 bits on every
architecture.
Then we can cast to void * or uintptr_t as needed.

Later, Juan.