On Tue, Mar 10, 2020 at 01:13:21PM +0200, Liran Alon wrote: > > On 10/03/2020 11:34, Michael S. Tsirkin wrote: > > On Tue, Mar 10, 2020 at 01:54:04AM +0200, Liran Alon wrote: > > > This is VMware documented functionallity that some guests rely on. > > > Returns the BIOS UUID of the current virtual machine. > > > > > > Reviewed-by: Nikita Leshenko <nikita.leshche...@oracle.com> > > > Signed-off-by: Liran Alon <liran.a...@oracle.com> > > So this at least seems guest-visible. > > > > So I suspect you need to add properties to > > disable this for old machine types, to avoid > > breaking compatibility with live-migration. > > It is indeed guest visible. > In theory, you are right that for every guest-visible change, we should make > sure to expose it to only new machine-types. > > However, in this case, I feel it just unnecessary over-complicates the code. > I don't see how a guest which previously failed to use this command, will > fail because after Live-Migration it could succeed.
The reverse can happen, start guest on a new qemu, command seems to work, then we migrate and it fails. And I guess this applies to the version right? > If you insist, I will add such functionality. In that case, do you think a > single flag will suffice for the addition of all new commands > (i.e. "commands-version" that it's number specifies set of commands to > expose), or you want to have a per-command flag? > > -Liran Can be a single flag but I'd just do it a boolean that enables a group of commands. E.g. "commands-v2". -- MST
