On Thu, Apr 18, 2019 at 01:19:41AM +0200, Thomas Gleixner wrote: > On Wed, 17 Apr 2019, Fenghua Yu wrote: > > > The kernel option clearcpuid currently only takes feature bit which > > can be changed from kernel to kernel. > > > > Extend clearcpuid to use cap flag string, which is defined in > > x86_cap_flags[] and won't be changed from kernel to kernel. > > And user can easily get the cap flag string from /proc/cpuinfo. > > If your machine dies because init triggers #AC then please explain how that > easily can be read from /proc/cpuinfo and how the sysadmin can figure out > what the heck he needs to write on the kernel command line. > > The whole 'clearcpuid' thing should have never been merged. It's a pure > testing/debugging thing. And no, we are not going to proliferate it and > extend it for dubious value. Quite the contrary, we should simply rip it > out. So I can remove the four 'clearcpuid' related patches 0018-0021 in the next version, right? > > Add a simple 'noac' or whatever command line option, which is documented > proper and can easily be mapped to a #AC crash during boot. OK. I will do this. Thanks. -Fenghua