Re: [Qemu-devel] [WIP PATCH 00/24] IDE cleanups, initial work on AHCI rerror/werror=stop

[Michael S. Tsirkin]

On Mon, Oct 28, 2013 at 06:26:58PM +0100, Paolo Bonzini wrote:
> Il 28/10/2013 18:16, Michael S. Tsirkin ha scritto:
> > On Mon, Oct 28, 2013 at 05:43:16PM +0100, Paolo Bonzini wrote:
> >> Hi all,
> >>
> >> this is some cleanup to the IDE code that I started long ago
> >> and picked up again on my flight back from KVM Forum...
> >>
> >> The patches clean up the callbacks to prepare for implementing request
> >> retry for AHCI.  After these patches, PIO retry should work for AHCI and
> >> non-NCQ retry should be very close (you need an implementation of the
> >> new restart_dma callback).  NCQ retry and save/restore is AHCI-specific
> >> and has to be done separately, similar to how we do it for SCSI already.
> >>
> >> Patches 1-4 set up a new (incomplete) testcase.  Patches 5-13 are no-op
> >> cleanups, or so I hope.  Patches 14-23 genericize retry and make it
> >> "just work" for all adapters for PIO.  Patch 24 is another cleanup that
> >> could probably be moved earlier in the series.
> >>
> >> Throwing it out since I know Kevin and mst are working on AHCI, to avoid
> >> doing duplicate work.  Patches 2 and 4 are known to be racy and
> >> incomplete.  Extremely light testing, if something breaks tells me and
> >> I'll look at it.
> > 
> > Well ATM win7 boot is broken with non NCQ (crash on boot).
> > Do you patches help?
> 
> No, these are for another feature that is missing for AHCI, that is
> support for stopping the VM on I/O errors.  It is
> https://bugzilla.redhat.com/show_bug.cgi?id=887844

Hmm. Actually maybe there was an io error... is there
an easy way to find out?

> > Also, without NCQ win 7 boot will sometime hang.
> > The following patch by Alex makes it behave better:
> > it still sometimes hangs for a very long time but with the patch it
> > will after a long time proceed. Sometimes it proceeds normally.
> 
> Yeah, I saw you and Kevin discuss it on IRC.
> 
> Paolo
> 
> > diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
> > index a8be62c..fbea9e8 100644
> > --- a/hw/ide/ahci.c
> > +++ b/hw/ide/ahci.c
> > @@ -961,7 +961,8 @@ static int handle_cmd(AHCIState *s, int port, int slot)
> >          /* We're ready to process the command in FIS byte 2. */
> >          ide_exec_cmd(&s->dev[port].port, cmd_fis[2]);
> >  
> > -        if (s->dev[port].port.ifs[0].status & READY_STAT) {
> > +        if ((s->dev[port].port.ifs[0].status & 
> > (READY_STAT|DRQ_STAT|BUSY_STAT)) ==
> > +            READY_STAT) {
> >              ahci_write_fis_d2h(&s->dev[port], cmd_fis);
> >          }
> >      }
> >