Re: [PATCH v1 05/26] qemu_domain_address: Reformat qemuDomainAssignS390Addresses()
On Mon, 30 Nov 2020 11:18:20 +0100
Michal Privoznik <mprivozn(a)redhat.com> wrote:
On 11/30/20 10:38 AM, Thomas Huth wrote:
> On 27/11/2020 16.02, Michal Privoznik wrote:
>> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
>> ---
>> src/qemu/qemu_domain_address.c | 10 ++++------
>> 1 file changed, 4 insertions(+), 6 deletions(-)
>> } else if (virQEMUCapsGet(qemuCaps,
QEMU_CAPS_VIRTIO_S390)) {
>
> Not related to your patch, but an idea for a future clean-up: That
> QEMU_CAPS_VIRTIO_S390 seems to belong to the ancient "s390-virtio"
(without
> ccw) machine that has been removed in QEMU v2.6 already:
>
> https://git.qemu.org/?p=qemu.git;a=commitdiff;h=7b3fdbd9a82
> https://git.qemu.org/?p=qemu.git;a=commitdiff;h=3538fb6f89d
>
> IIRC, that machine was already considered as deprecated since a couple of
> earlier QEMU releases, so I really doubt that anybody is still using that in
> production today.
>
> Thus I think that all code related to QEMU_CAPS_VIRTIO_S390 could likely be
> removed from libvirt nowadays.
That is even better idea. But currently libvirt supports QEMU-1.5.0 and
newer. So I think we shouldn't remove that until the minimum version is
bumped even though we think feature has no users.
https://gitlab.com/libvirt/libvirt/-/commit/c1bc9c662b4
Although, it might be about time to look again what is the oldest QEMU
we need to support.
Would be great if you could bump it enough to get rid of the old
virtio-s390 transport :)
FWIW, virtio-ccw was introduced in QEMU 1.4, and became the default
with QEMU 2.4, although it had supplanted virtio-s390 well before that.
What are the criteria for possibly removing support for a feature in
libvirt: that nobody would use it in practice, or that nobody would be
able to use it?