Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation

[Arnd Bergmann]

On Wednesday 12 November 2014 16:52:25 Paolo Bonzini wrote:
> On 12/11/2014 16:39, Peter Maydell wrote:
> > > Definitely, I think having the OS manually program the BARs only makes 
> > > sense
> > > in an environment where you don't have a full-featured boot loader or you
> > > don't trust it. In servers and virtual machines, the PCI bus should 
> > > always come
> > > fully set up. This also implies that the OS should not have to deal with
> > > registers for setting up the translation between PCI and system address
> > > ranges.
> >
> > It seems to me like complicated stuff like that definitely belongs
> > in the UEFI/bootloader blob, though. I'd rather QEMU just modelled
> > the hardware and let the guest (or the firmware, which is guest
> > code from QEMU's point of view) set it up however it wants.
> 
> It definitely doesn't belong in QEMU!

The easiest option would probably be not make all PCI devices have
fixed BARs and not even allow them to be changed. I believe this is
what kvmtool does, but I can see how supporting both modes is much
harder than either one.

How does it work on x86 with qemu?

        Arnd