On Mon, Jan 03, 2022 at 16:56:32 +0100, Ján Tomko wrote:
On a Monday in 2022, Peter Krempa wrote:
As a workaround for users using 'libvirt-7.9' and 'libvirt-7.10' with 'qemu-6.2' who wish to use device hot-unplug we are going to be suggesting to filter out the 'device.json' qemu capability via either the global 'qemu.conf' config:
capability_filters = [ "device.json" ]
or the per-VM XML capability override:
<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
[...]
<qemu:capabilities> <qemu:del capability='device.json'/> </qemu:capabilities> </domain>
Doing this poisons the capability name 'device.json' for any further use, so to ensure that we can re-add JSON usage for -device also for users which filtered it out originally once it's fixed in qemu we need to condemn the old name and add a new one.
To achieve this the old capability is renamed to 'X_QEMU_CAPS_DEVICE_JSON_BROKEN' and a new capability 'QEMU_CAPS_DEVICE_JSON' is mapped to 'device.json-fixed'. For now we
I am not a fan of the new string but we can change it later once it's clear how to probe for this in QEMU.
In fact, I can leave this commit out for now, or replace it by just noting in qemu_capabilities.h that the flag name was poisoned by recomending users to filter it out and a new one must be picked when re-instating this feature.