Re: [Qemu-devel] BIOS regression since v2.3.0 (misaligned longword i/o to address 0xffff)

[Stefan Weil]

Am 27.07.2015 um 08:24 schrieb Stefan Weil:
> Am 27.07.2015 um 07:49 schrieb Stefan Weil:
> > Am 26.07.2015 um 21:32 schrieb Stefan Weil:
> > > Hi,
> > >
> > > since commit 21f5826a04d38e19488f917e1eef22751490c769
> > > "seabios: update to 1.8.0 release" there is a misaligned i/o access
> > > caused by the PC BIOS.
> > >
> > > QEMU's PC emulation (qemu-system-i386, qemu-system-x86_64)
> > > with enabled trace backend reports the misaligned i/o access
> > > when running the BIOS code:
> > >
> > > Misaligned i/o to address 0x0000ffff with size 4 for memory region io
> > >
> > > ("to address 0x0000ffff" was added by my debug code)
> > >
> > > This issue was reported by users of QEMU for Windows,
> > > but it is not Windows specific.
> > >
> > > Regards
> > > Stefan
> >
> >
> > Sorry, I did not notice that the code which reports misaligned access is
> > not part of the official QEMU code.
> >
> > Here is the patch for memory.c which adds it:
> >
> > @@ -1073,6 +1119,9 @@ bool memory_region_access_valid(MemoryRegion *mr,
> >      int access_size, i;
> >
> >      if (!mr->ops->valid.unaligned && (addr & (size - 1))) {
> > +        fprintf(stderr, "Misaligned i/o to address %08" HWADDR_PRIx
> > +                        " with size %u for memory region %s\n",
> > +                addr, size, mr->name);
> >          return false;
> >      }
> >
> > Is the misaligned i/o access done by the BIOS code a feature or a bug?
> >
> > Regards
> > Stefan

Please ignore my last e-mail. This one is the commit reported
by git bisect for seabios:

457ba42878bd9f704e5a6c1c7bc7fcced686fe4e is the first bad commit
commit 457ba42878bd9f704e5a6c1c7bc7fcced686fe4e
Author: Paolo Bonzini <address@hidden>
Date:   Thu May 15 13:22:28 2014 +0200

    smm: complete SMM setup

    SMI generation requires two bits to be set in PIIX4, one for APMC
    interrupts specifically and a general one.

    For Q35 it is the same, plus it is a good thing to lock SMIs after
    enabling them.

    Signed-off-by: Paolo Bonzini <address@hidden>

:040000 040000 5bfd5601430bc5263ac0a6f8a15a131f3bc8678e 
5e0901b1c5ae4c79ed4c34c8bd27e7daf9006086 M    src