Re: [Qemu-devel] [PATCH v3] hw/arm/virt: Add high MMIO PCI region

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 29 Jul 2015 12:48:18 +0300
Pavel Fedin <p.fedin@samsung.com> wrote:

>  Hello!
> 
> > this is wrong since dword is too small for values of high memory
> > use aml_qword_memory() instead
> 
>  Thanks, will fix it.
> 
> > since window is at fixed position and it's not possible for guest to
> > move base address of the range, make AddressMaximum the same as AddressMinimum i.e.
> 
>  But it is anyway not possible. On ARM hardware PCI range addresses are normally hardwired (at least
> on simple machine which we are emulating), and the OS doesn't have control over it. And i'm not sure
> whether some hotplugged memory can be overlaid on top of it. This is because on PC PCI is a core
> system bus, which represents all address space, and RAM is kind of plugged into it. On ARM another
> buses are used for system core, and PCI controller, from the point of view of that bus, is a single
> device, which occupies some space. So AFAIK having something else on top of PCI hole on ARM would be
> abnormal.

I don't suggest to have something mapped on top of the window,
Suggestion was to just use the same value for
AddressMaximum and AddressMinimum arguments in aml_qword_memory() call.

> 
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
> 
> 
>