Re: [Qemu-devel] [PATCH 03/28] ide-test: add test for werror=stop

[John Snow <jsnow@redhat.com>]

On 07/31/2014 06:58 AM, Stefan Hajnoczi wrote:
> On Mon, Jul 07, 2014 at 02:17:44PM -0400, John Snow wrote:
>> +static void test_retry_flush(void)
>> +{
>> +    uint8_t data;
>> +    const char *s;
>> +
>> +    prepare_blkdebug_script(debug_path, "flush_to_disk");
>> +
>> +    ide_test_start(
>> +        "-vnc none "
>> +        "-drive file=blkdebug:%s:%s,if=ide,cache=writeback,rerror=stop,werror=stop",
>> +        debug_path, tmp_path);
>> +
>> +    /* FLUSH CACHE command on device 0*/
>> +    outb(IDE_BASE + reg_device, 0);
>> +    outb(IDE_BASE + reg_command, CMD_FLUSH_CACHE);
>> +
>> +    /* Check status while request is in flight*/
>> +    data = inb(IDE_BASE + reg_status);
>> +    assert_bit_set(data, BSY | DRDY);
>> +    assert_bit_clear(data, DF | ERR | DRQ);
>> +
>> +    sleep(1);                    /* HACK: wait for event */
>> +
>> +    /* Complete the command */
>> +    s = "{'execute':'cont' }";
>> +    while (!qmp(s)) {
>> +        s = "";
>> +        sleep(1);
>> +    }
> I guess we're supposed to wait for the block I/O error event when the
> machine stops.  Please implement that and replace this polling loop.
>
> See the STOP event in docs/qmp/qmp-events.txt.
>
Paolo: I edited in a bit to check for the STOP event instead of sleeping 
in V2, but what's the point of setting s = "" and sleeping and resending 
a blank string? Can't we just g_assert(qmp(s)) the first go around, 
provided the STOP event has already occurred?

It works in practice, but I am curious.

--J