Re: [Qemu-devel] [PATCH] hw/arm/virt: Allow zero address for PCI IO space

[Laurent Vivier <lvivier@redhat.com>]

On 13/10/2015 15:55, Peter Maydell wrote:
> On 13 October 2015 at 14:25, Peter Maydell <peter.maydell@linaro.org> wrote:
>> On 13 October 2015 at 14:19, Michael S. Tsirkin <mst@redhat.com> wrote:
>>> On Tue, Oct 13, 2015 at 02:12:34PM +0100, Peter Maydell wrote:
>>>> Well, if we're going to go around and fix the machines which
>>>> don't get things right, I guess. It's a shame the default for
>>>> the global is "this machine is broken", because now every
>>>> new machine will default unnecessarily to broken, and there's
>>>> no way to grep the source tree for machines which need fixing.
>>
>>> It'd be easy enough to revert the logic if someone's willing to start on
>>> this.  I'm reluctant to make this patchset depend on changing all
>>> machines, but if you think I'm wrong, pls let me know.
>>
>> Most machines don't have a PCI controller, luckily.
>> I'll have a look at how many files it would touch...
> 
> So, first up I'm happy that the gpex and versatile
> pci controllers don't have this problem (the way they
> set up the mmio and io windows means there won't be
> overlaps). That leaves the following pci controllers,
> which I've listed with the source files which define machines
> that use them:
> 
> hw/pci-host/pbm
>  hw/sparc64/sun4u.c
> hw/pci-host/bonito
>  hw/mips/mips_fulong2e.c
> hw/pci-host/grackle
>  hw/pc/mac_oldworld.c
> hw/pci-host/piix
>  [the x86 systems]
> hw/pci-host/ppce500
>  hw/ppc/e500.c
> hw/pci-host/prep
>  hw/ppc/prep.c
> hw/pci-host/q35
>  [x86 systems]
> hw/pci-host/uninorth
>  hw/ppc/mac_newworld.c
> hw/alpha/typhoon
>  used in hw/alpha/dp264.c
> hw/mips/gt64xxx_pci
>  hw/mips/mips_malta.c
> hw/ppc/ppc4xx_pci
>  hw/ppc/ppc440_bamboo.c
> hw/ppc/spapr_pci
>  hw/ppc/spapr.c [already marked as '0 addrs ok']
> hw/s390/s390-pci-bus
>  hw/s390/s390-virtio-ccw.c
> hw/sh4/sh_pci
>  hw/sh4/rd2.c
> 
> So we'd need to touch perhaps fifteen files in total.
> 
> I don't insist we do that rather than applying this particular
> patch, but I don't think it's a huge effort.

I'm going to remove the zero address checking and try to start a qemu
for each of them to see which ones are broken.
I remember from a previous discussion on my initial patch that x86
should be ok.

> thanks
> -- PMM
> 
Laurent