On Sat, Feb 18, 2023 at 01:14:30PM -0800, Rick Edgecombe wrote: > If an xfeature is saved in a buffer, the xfeature's bit will be set in > xsave->header.xfeatures. The CPU may opt to not save the xfeature if it > is in it's init state. In this case the xfeature buffer address cannot > be retrieved with get_xsave_addr(). > > Future patches will need to handle the case of writing to an xfeature > that may not be saved. So provide helpers to init an xfeature in an > xsave buffer. > > This could of course be done directly by reaching into the xsave buffer, > however this would not be robust against future changes to optimize the > xsave buffer by compacting it. In that case the xsave buffer would need > to be re-arranged as well. So the logic properly belongs encapsulated > in a helper where the logic can be unified. > > Tested-by: Pengfei Xu <pengfei.xu@xxxxxxxxx> > Tested-by: John Allen <john.allen@xxxxxxx> > Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -- Kees Cook
