> From: Hansen, Dave > On 03/02/2015 04:09 PM, Yu, Fenghua wrote: > > Xsaves has been tested by QA since 3.17 with or without MPX. I'm not > > aware of reported issues. > > > > But MPX is the only code to call the get_xsave_addr kernel API. > > Though it has been tested before on upstream MPX code. > > Has it? I'm fairly sure I've never explicitly tested it. I'm also doubting > now > that I've *ever* seen it work without booting with 'noxsaves'.
QA did test conflict between MPX and xsaves long time before MPX went upstream. But seems the conflict happened again at some point... > > > What changes in your new MPX code? > > I just discovered it when adding a new feature. I actually backed out all of > my > changes before reporting this issue. I'm running a completely untouched 4.0- > rc1 kernel with the config I attached a moment ago. MPX and xsaves are supposed to work well on 4.0-rc1. If not, definitely the code is broken again somehow. > If I boot with 'noxsaves', MPX works fine. If I boot without it, the kernel > never sees the values that userspace sets in the "bndcsr" register. We are supposed to handle this issue long time ago. I can try to reproduce the issue with the config. Thanks. -Fenghua
