On Wed, Jan 20, 2021 at 03:12:41PM -0500, Eduardo Habkost wrote: > The ordering semantics of +feature/-feature is tricky and not > obvious, and it requires a custom option parser. Deprecate that > syntax so we can eventually remove the custom -cpu option parser > and plus_features/minus_features global variables in i386. > > Signed-off-by: Eduardo Habkost <ehabk...@redhat.com> > --- > docs/system/deprecated.rst | 14 ++++++++++++++ > 1 file changed, 14 insertions(+)
Ideally we would also print a warning on stderr when this deprecated style is used. > > diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst > index e20bfcb17a4..2c4b8d4b78b 100644 > --- a/docs/system/deprecated.rst > +++ b/docs/system/deprecated.rst > @@ -127,6 +127,20 @@ Drives with interface types other than ``if=none`` are > for onboard > devices. It is possible to use drives the board doesn't pick up with > -device. This usage is now deprecated. Use ``if=none`` instead. > > +``-cpu`` ``+feature`` and ``-feature`` syntax (since 6.0.0) > +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' > + > +The ``-cpu ...,+feature`` and ``-cpu ...,-feature`` syntax for > +enabling and disabling CPU features is deprecated. The ``-cpu > +...,feature=on`` or ``-cpu ...,feature=off`` should be used > +instead. > + > +Note that the ordering semantics of ``-cpu ...,-feature,+feature`` > +is different from ``-cpu ...,feature=off,feature=on``. With the > +former, the feature got disabled because ``-feature`` had > +precedence, but with the latter the feature will be enabled > +because options are applied in the order they appear. > + 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 :|
