[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] address order of virtio-mmio devices
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] address order of virtio-mmio devices |
Date: |
Fri, 30 Jan 2015 12:38:30 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
On 01/30/15 11:48, Daniel P. Berrange wrote:
> 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
Please note that (as far as I understand) the patch that I referenced is
indeed very new, it's not part of v3.18, but the reversal can easily be
seen with v3.18. In other words, the kernel patch I referenced
introduces no functional change, it just reorganizes stuff in the kernel
(AIUI), with the benefit of killing a superfluous field.
The reason I referenced it because its *commit message* gives good
background. If we really wanted to find the kernel change that reversed
the traversal, we'd have to talk to Grant and/or bisect the kernel.
Thanks
Laszlo
> 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
>
- Re: [Qemu-devel] address order of virtio-mmio devices, (continued)
- Re: [Qemu-devel] address order of virtio-mmio devices, Laszlo Ersek, 2015/01/29
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/29
- Re: [Qemu-devel] address order of virtio-mmio devices, Daniel P. Berrange, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Laszlo Ersek, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Daniel P. Berrange, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Laszlo Ersek, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices,
Laszlo Ersek <=
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Laszlo Ersek, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/30
- Re: [Qemu-devel] address order of virtio-mmio devices, Richard W.M. Jones, 2015/01/29
- Re: [Qemu-devel] address order of virtio-mmio devices, Peter Maydell, 2015/01/29
- Re: [Qemu-devel] address order of virtio-mmio devices, Laszlo Ersek, 2015/01/29