Re: [Qemu-devel] [Qemu-ppc] [PATCH v2] pci: allow 0 address for PCI IO/MEM regions

[Peter Maydell]

On 23 July 2015 at 22:19, Peter Maydell <address@hidden> wrote:
> On 23 July 2015 at 22:10, Michael S. Tsirkin <address@hidden> wrote:
>> On Thu, Jul 23, 2015 at 10:00:30PM +0100, Peter Maydell wrote:
>>> (Also, none of our PCI device models actually try to do
>>> the "BAR at zero means I won't respond" behaviour, which
>>> presumably they might do in real life.)
>
>> Maybe some devices do this, but I'm guessing not all of them,
>> since there's no hint in the pci spec that they should.
>
> I think this depends on which version of the spec you
> read.

Bikeshedding about ancient specs aside, I think it's the
bugs in the PC model's memory region priorities that
are the real reason the special case of zero is sticking
around. If we fixed those we should be able to drop it.

-- PMM