Re: [Qemu-devel] [PULL 00/14] Migration pull request

[Kevin Wolf <kwolf@redhat.com>]

Am 20.11.2015 um 14:44 hat Peter Lieven geschrieben:
> Am 20.11.2015 um 12:33 schrieb Peter Maydell:
> > On 20 November 2015 at 09:38, Peter Lieven <pl@kamp.de> wrote:
> >> I wonder if there is a glitch in the PIO implementation of test-ide.c. As far as I understand the specs
> >> it is not allowed to read data while the BSY flag is set. With the following change to the test-ide script
> >> the test does not race:
> >>
> >> diff --git a/tests/ide-test.c b/tests/ide-test.c
> >> index d1014bb..ab0489e 100644
> >> --- a/tests/ide-test.c
> >> +++ b/tests/ide-test.c
> >> @@ -728,6 +728,7 @@ static void cdrom_pio_impl(int nblocks)
> >>      for (i = 0; i < DIV_ROUND_UP(rxsize, limit); i++) {
> >>          size_t offset = i * (limit / 2);
> >>          size_t rem = (rxsize / 2) - offset;
> >> +        ide_wait_clear(BSY);
> >>          for (j = 0; j < MIN((limit / 2), rem); j++) {
> >>              rx[offset + j] = le16_to_cpu(inw(IDE_BASE + reg_data));
> >>          }
> >>
> >> Note: in the old sync version of the ATAPI PIO implementation this could not happen.
> > This certainly fixes the stalls for me, though I don't know enough
> > IDE to say whether it is the correct fix.
> Thanks for testing.
> 
> I hope that John or Kevin can verify this fix?

The fix looks correct to me.

While you're improving the test, you could also add an assertion that
DRQ is set after BSY has been cleared.

Kevin