On Tue, Jun 25, 2019 at 01:18:01PM -0500, Eric Blake wrote:
On 6/25/19 11:16 AM, Igor Mammedov wrote:
Fallback might affect guest or worse whole host performance or functionality if backing file were used to share guest RAM with another process.
Patch deprecates fallback so that we could remove it in future and ensure that QEMU will provide expected behavior and fail if it can't use user provided backing file.
Signed-off-by: Igor Mammedov <imammedo@redhat.com> --- v2: * improve text language (Markus Armbruster <armbru@redhat.com>)
Is this deprecation introspectible? Does it need to be?
Do we even need a deprecation period, or can we declare this a bug fix (it was a bug that we didn't fail outright on an impossible request) and do it immediately?
I think it is hard to call it a bug when we added explicit extra code to make it work as it does today. It is really a misguided feature.
If it is not a bug fix, perhaps it could be made introspectible by having a new boolean parameter to opt in to the failure now, rather than 2 releases from now?
From libvirt's POV I don't see a need for introspection. There's no special action we need to take to deal with the new behaviour - it is ultimately just providing the behaviour we kind of assumed it already had.
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 :|