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Re: [Qemu-ppc] [PATCH] spapr-pci: remove io ports workaround

From: Alexey Kardashevskiy
Subject: Re: [Qemu-ppc] [PATCH] spapr-pci: remove io ports workaround
Date: Tue, 16 Jul 2013 18:37:31 +1000
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6

On 07/16/2013 06:32 PM, Alexander Graf wrote:
> Am 16.07.2013 um 08:20 schrieb Paolo Bonzini <address@hidden>:
>> Il 16/07/2013 07:19, Alexey Kardashevskiy ha scritto:
>>> In the past, IO space could not be mapped into the memory address space
>>> so we introduced a workaround for that. Nowadays it does not look
>>> necessary so we can remove the workaround and make sPAPR PCI
>>> configuration simplier.
>>> This also removes all byte swappings as it is not PHB's to take care
>>> of endiannes - devices should do convertion if they want to. And almost
>>> every PCI device which uses IO ports does that by registering IO ports
>>> region with memory_region_init_io() (Intel e1000, RTL8139, virtio).
>>> However VGA uses MemoryRegionPortio which does not support endiannes
>>> but it still expects the convertion to be done. For this case only,
>>> this patch adds LITTLE_ENDIAN flag to portio_ops. Tests on PPC64 show
>>> that other devices are not affected by this change. x86 systems should
>>> not suffer either as having LITTLE_ENDIAN there has no effect.
>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>> ---
>>> This removes bugs at least from SPAPR so any further fixes should be equal
>>> for all platforms and hopefully will break all platform altogether but not
>>> just PPC64-pSeries :)
>>> Did I miss anything here?
>> No, I don't think so.  The patch looks good.
> ... and will break all Mac targets again, no? Not to speak of non-ppc devices.

Like what? I do not mind/argue/discuss, may be it breaks, I am just looking
for good examples to test.


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