2018-02-01 15:45+0300, Roman Kagan: > 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. Exactly, thanks!
