Re: [Qemu-devel] address order of virtio-mmio devices

[Daniel P. Berrange]

On Fri, Jan 30, 2015 at 10:29:46AM +0000, Peter Maydell wrote:
> On 30 January 2015 at 09:54, Daniel P. Berrange <address@hidden> wrote:
> > While it is clear there is no solution that works correctly with all
> > kernels, I hate to think that we're going to stick with an ordering
> > that is clearly wrong for modern kernels, forever going forward. The
> > aarch64 world is only just starting out, so on balance I think we
> > should optimize for the future rather than the past, since that gives
> > right behaviour for orders of magnitude more people in the long term.
> 
> Yeah, I agree it's awkward. But I hate breaking people's
> working setups, and we have no guarantee the kernel won't
> change again in the future.
> 
> You could try asking the kernel folk to revert that patch on
> the basis that it breaks things...

Might be worth a shot - the patch is only a month old. Or at least do a
followup patch to put the ordering back the way it was, rather than plain
revert

Long term though it will be much better of AArch64 would just do PCI
instead of MMIO bus. Then we have proper device addressing which we
can control in a predictable manner that will be stable across hotplug
and unplug and migration.  I hear there's work on PCI for AArch64 but
is there a near term ETA yet ?

Regards,
Daniel
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