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

[John Snow]

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