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Re: [Qemu-devel] Posible regressions around spapr-dr-connector property
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[] |
Date: |
Fri, 04 Dec 2015 09:05:51 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
David Gibson <address@hidden> writes:
> On Thu, Dec 03, 2015 at 04:30:31PM +0100, Markus Armbruster wrote:
>> 1. Before commit 94649d4 "spapr: Don't use QOM [*] syntax for DR
>> connectors", the indexes were small integers:
>>
>> (qemu) info qom-tree
>> /machine (pseries-2.4-machine)
>> /unattached (container)
>> [...]
>> /device[5] (spapr-pci-host-bridge)
>> /address@hidden (qemu:memory-region)
>> /address@hidden (qemu:memory-region)
>> /address@hidden (qemu:memory-region)
>> /address@hidden (qemu:memory-region)
>> /pci.0 (PCI)
>> /address@hidden (qemu:memory-region)
>> /dr-connector[0] (spapr-dr-connector)
>> /dr-connector[1] (spapr-dr-connector)
>> /dr-connector[2] (spapr-dr-connector)
>> [...]
>>
>> Since then, they're big ones:
>>
>> /dr-connector[1073741824] (spapr-dr-connector)
>> /dr-connector[1073741825] (spapr-dr-connector)
>> /dr-connector[1073741826] (spapr-dr-connector)
>>
>> The commit message doesn't quite spell out this change, and I'm
>> therefore double-checkint it's intentional. Is it?
>
> Yes, it's intentional. The small integers were arbitrarily allocated
> by the QOM magic [*] code, whereas the big integers are actually
> meaningful values (essentially the DRC's global ID for the dynamic
> reconfiguration hypervisor interfaces).
Good.
>> 2. Before commit 6c2f9a1 "qapi: Make output visitor return qnull()
>> instead of NULL", qom-get returned {}:
>>
>> Since then, it returns null:
>>
>> QMP> { "execute": "qom-get", "arguments": { "path":
>> "/machine/unattached/device[5]/dr-connector[1073741950]", "property": "fdt"
>> } }
>> {"return": null}
>>
>> Does anyone care?
>
> Hm, I'm guessing this is a case where fdt is NULL internally. Which I
Yes.
> think will happen before a device gets hotplugged into the DRC. In
> that case null seems more correct to me than {}, since {} would also
> be what's shown for a present-but-empty device tree.
It was {} in 2.4. Changing it to null so we can distingish "nothing"
from "empty" is an incompatible change. May make sense anyway, but I
can't judge it.
Thanks!
- [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], Markus Armbruster, 2015/12/03
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], David Gibson, 2015/12/03
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[],
Markus Armbruster <=
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], David Gibson, 2015/12/04
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], Markus Armbruster, 2015/12/04
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], Peter Maydell, 2015/12/04
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], David Gibson, 2015/12/07
- Re: [Qemu-devel] Posible regressions around spapr-dr-connector property drc-connector[], Eric Blake, 2015/12/07