On Wed, Jan 16, 2019 at 03:46:12PM +0100, Andrea Bolognani wrote:
On Wed, 2019-01-16 at 14:19 +0000, Daniel P. Berrangé wrote:
On Wed, Jan 16, 2019 at 03:07:07PM +0100, Andrea Bolognani wrote:
On Wed, 2019-01-16 at 11:13 +0000, Daniel P. Berrangé wrote:
The enum should cover all existing reasonably expected configs. Sure I imagine we might miss a few, especially for obscure architectures or hypervisors, but that would just be bugs to be fixed
Until we've fixed said bugs, guests using such models would just disappear though, wouldn't they? That doesn't sound acceptable.
We could do a multi-step conversion. First define an enum and report all known enum values in the domain capabilities. Taint any guest using a nic with doesn't match. A year or so later, then finally enforce the enum usage.
That will still result in guests disappearing at some point, which is not something that we're generally okay with. Why would it be any different this time around?
No change we make is perfectly risk free. We would want to have reasonable confidence that the initial enum is a good as we can practically make it. The tainting check & log is a way to identify if we made some mistakes - hopefully we won't have. If users do report it though, we'll be able to fix it. If we get no reports for a reasonable period of time (minimum 12 months), it is OK to assume we've not broken anything that we believe has users.
And defining even the incomplete enum would require someone to be familiar with all drivers in order to know which models are commonly used, or at all available.
It isn't as bad as it seems. VMWare has whitelisted names, Hyperv doesn't report models at all, Xen is a small finite set. QEMU is the only hard one given the huge set of system emulators.
If we're willing to leave some theoretical users of impractical network devices in the dust, then coming up with a reasonably small list for QEMU is not too difficult either... But see above :)
The QEMU list won't be small - it'll be large given all archs ! Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|