Re: [Qemu-devel] [PATCH] s390-ccw: Fix alignment for CCW1

[Farhan Ali]

On 08/28/2017 04:22 AM, Cornelia Huck wrote:
> On Fri, 25 Aug 2017 11:05:30 -0400
> Farhan Ali <address@hidden> wrote:
>
> > On 08/25/2017 10:04 AM, Cornelia Huck wrote:
> > > On Fri, 25 Aug 2017 09:24:46 -0400
> > > Farhan Ali <address@hidden> wrote:
> > >
> > > > The commit 198c0d1f9df8c4 s390x/css: check ccw address validity
> > > > exposes an alignment issue in ccw bios.
> > > >
> > > > According to PoP the CCW must be doubleword aligned. Let's fix
> > > > this in the bios.
> > > >
> > > > Cc: address@hidden
> > > > Signed-off-by: Farhan Ali <address@hidden>
> > > > Reviewed-by: Halil Pasic <address@hidden>
> > > > Reviewed-by: Eric Farman <address@hidden>
> > > > Acked-by: Christian Borntraeger <address@hidden>
> > > > ---
> > > >  pc-bios/s390-ccw/cio.h | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/pc-bios/s390-ccw/cio.h b/pc-bios/s390-ccw/cio.h
> > > > index f5b4549..55eaeee 100644
> > > > --- a/pc-bios/s390-ccw/cio.h
> > > > +++ b/pc-bios/s390-ccw/cio.h
> > > > @@ -133,7 +133,7 @@ struct ccw1 {
> > > >      __u8 flags;
> > > >      __u16 count;
> > > >      __u32 cda;
> > > > -} __attribute__ ((packed));
> > > > +} __attribute__ ((packed, aligned(8)));
> > > >
> > > >  #define CCW_FLAG_DC              0x80
> > > >  #define CCW_FLAG_CC              0x40
> > >
> > > Currently testing.
> > >
> > > This looks obviously right, but did you figure out what the (probably
> > > unrelated) other failure was?
> >
> > That is still under investigation, for some reason it only fails for an
> > LDL DASD and it works for SCSIs and CDL DASD.
>
> Which are the symptoms of the failure? I'd like to understand this
> before I update the (currently working by accident) bios with an
> updated version.
>
> I'll just apply the patch for now.

Well it's seems like the failure for LDL DASD could be a disk setup 
failure. We tried the test on a different environment with LDL disks and 
everything worked fine with the patch applied.