On 5/26/25 14:40, Peter Krempa via Devel wrote:
On Thu, May 22, 2025 at 02:03:16 -0400, Collin Walling wrote:
To ease the user with defining a guest with a migratable CPU model,
disclaimer: I'm not an expert on:
- libvirt's cpu driver
- s390x cpu etc.
let's disable the deprecated features from the get-go. If these
features are still desired, they may be reenabled via the
deprecated_features='on' attribute.
I'd expect that anything that happens with cpu model (as it has guest
visible implications [2]) would happen also in XML ...
Some existing tests utilize this updated behavior, so update the CPU
features on the corresponding args files.
Signed-off-by: Collin Walling <wall...@linux.ibm.com>
---
src/qemu/qemu_process.c | 11 +++++++++++
.../default-video-type-s390x.s390x-latest.args | 2 +-
...hostdev-vfio-zpci-ccw-memballoon.s390x-latest.args | 2 +-
.../launch-security-s390-pv.s390x-latest.args | 2 +-
...0-default-cpu-kvm-ccw-virtio-4.2.s390x-latest.args | 2 +-
.../s390-defaultconsole.s390x-latest.args | 2 +-
... which doesn't seem to be the case as just the .args files changed.
Do the mocked tests perform a cpu model expansion which is done when
starting a domain?
I tested Collins changes and when dumping the active domain xml the
expanded CPU model and also deprecated_features='off' is included if
deprecated_features was not already included in the persisted domain xml.
So won't this actually break the guest ABI?
I think Daniel's old email can shed some light on that question.
https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/message/MCDGWIF2LZGKM5HYPE34QZVZPGTMQL7N/
My understanding is that guest ABI does not include guaranties how a CPU
model is expanded and therefore this change does not break the guest ABI.
--
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Boris Fiuczynski
IBM Deutschland Research & Development GmbH
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