On Wed, Jan 31, 2018 at 07:18:12PM +0100, Radim Krčmář wrote: > 2018-01-31 16:56+0300, Roman Kagan: > I have completely missed this series in the past, sorry. No wonder, everybody was too busy with all this Meltdown+Spectre stuff. > > + /* > > + * Per spec, bits 32-47 contain the extra "flag number". However, we > > + * have no use for it, and in all known usecases it is zero, so just > > + * require it here. > > + */ > > The spec says: > > FlagNumber specifies the relative index of the event flag that the > caller wants to set within the target SIEF area. This number is > relative to the base flag number associated with the port. This smells like an overdesign to me. Anyway we've never seen non-zero FlagNumbers. The guest code in Linux doesn't even define a way to pass such a FlagNumber. > Don't we want to pass the flag into userspace? To be future-proof in case there turns out to be a user for non-zero FlagNumber? Makes sense, will respin with that. Thanks, Roman.
