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From: Peter Maydell <peter.maydell@linaro.org>
Date: Mon, 27 Jul 2015 16:51:56 +0100
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Subject: Re: [Qemu-devel] [PATCH v3] hw/arm/virt: Add high MMIO PCI region
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>, Alexander Graf <agraf@suse.de>, Pavel Fedin <p.fedin@samsung.com>, QEMU Developers <qemu-devel@nongnu.org>, Paolo Bonzini <pbonzini@redhat.com>

On 27 July 2015 at 16:18, Michael S. Tsirkin <mst@redhat.com> wrote:
> It's more a question of figuring out what does real hardware do.
> It's true, PIIX has this "everything that isn't memory is PCI"
> assumption. We do this for Q35 but I'm not even sure it's the
> right thing to do there.
>
> If as you say real ARM hardware doesn't work like this, then QEMU
> shouldn't do this for ARM.

Real ARM hardware might do a variety of things varying between
"we just have some windows" and "we do things exactly like
how an x86 PC does". The architecture doesn't care.

I don't know what the restrictions of the kernel's "generic
PCIe" handling are, whether it insists on specific windows
or can handle the "everything in the background is a window"
configuration as well. The dt binding doc for it implies not.

thanks
-- PMM