[libvirt] [PATCH v1 00/26] move qemucaps validations from qemu_command to qemu_domain

[Peter Krempa]

On Tue, Dec 10, 2019 at 09:58:38 +0000, Daniel Berrange wrote:
> On Mon, Dec 09, 2019 at 08:15:05PM -0300, Daniel Henrique Barboza wrote:
> > (series based on master commit 97cafa610ecf5)
> > 
> > This work was proposed by Cole in [1]. This is Cole's reasoning for
> > it, copy/pasted from [1]:
> > 
> > -------
> > The benefits of moving to validate time is that XML is rejected by
> > 'virsh define' rather than at 'virsh start' time. It also makes it easier
> > to follow the cli building code, and makes it easier to verify qemu_command.c
> > test suite code coverage for the important stuff like covering every CLI
> > option. It's also a good intermediate step for sharing validation with
> > domain capabilities building, like is done presently for rng models.
> > -------
> 
> I've not looked at the patches, but surely moving this validate from
> start time, to be define time errors is going to cause functional
> regressions in our ABI behaviour.
> 
> My libvirtd daemons installs have many XML files defined which will
> fail validation at various points in time, depending on what QEMU
> builds I happen to have deployed. I only need them to pass the
> validation when actually starting the VM.

Validation is not done on the persistent or status XML files exactly for
this reason.

It's re-done when starting the VM so this should not be an issue.