Re: [Qemu-devel] BUG: Re: [PATCH v3 11/14] ioport: Switch dispatching to memory core layer

[Edgar E. Iglesias]

On Sat, Jul 20, 2013 at 12:11:34PM +0200, Paolo Bonzini wrote:
> Il 20/07/2013 03:11, Alexey Kardashevskiy ha scritto:
> > On 07/20/2013 10:55 AM, Alexey Kardashevskiy wrote:
> >> On 07/20/2013 01:48 AM, Alexey Kardashevskiy wrote:
> >>> Ok. So.
> >>>
> >>> What broke is...
> >>> I could try explaining but backtraces are lot better :)
> >>>
> >>> Shortly - virtio_pci_config_ops.endianness was ignored before (was bad but
> >>> we had a workaround in spapr_io_ops), now it works so double swap happens
> >>> and everything gets broken.
> >>>
> >>> If we talk about VGA (in powerpc, it is all about powerpc), I guess
> >>> memory_region_iorange_write() will go through mr->ops->old_portio branch
> >>> and won't do any byte swapping (so spapr_io_ops will do the job), so we 
> >>> are
> >>> fine here. I do not understand yet why it works on mac99 though, too late
> >>> here :)
> >>
> >> I understood. VGA does not work for mac99 either with this command line:
> >> ./qemu-system-ppc64 -m "1024" -M "mac99" -vga "std"
> >> So it works for pseries only because of parity bug in spapr_io_ops.
> 
> Yes, this is what Herve was fixing for PREP too.
> 
> > oops. I am wrong and VGA works on mac99 in upstream because isa_mmio_ops
> > does the swapping in this case and portio_ops does not swap (in upstream).
> 
> Uff... I guess we have to look at all cases for big-endian machines, and
> make sure there is an odd number of exchanges.  Aurelien/Alex/Herve,
> where can I find images for mips malta, mips jazz, ppc4xx and prep?
> Edgar, what about sh4eb (IIRC one of the two machine types supported PCI)?

Sorry, I don't know (I haven't done much SH).

Best regards,
Edgar