On Sat, 6 Jan 2018, Dave Hansen wrote: > On 01/06/2018 09:41 AM, Van De Ven, Arjan wrote: > >>>> .macro DISABLE_IBRS > >>>> - ALTERNATIVE "jmp .Lskip_\@", "", X86_FEATURE_SPEC_CTRL > >>>> + testl $1, dynamic_ibrs > >>> On every system call we end up hammering on this 'dynamic_ibrs' > >>> variable. And it looks like it can be flipped via the IPI mechanism. > >>> > >>> Would it make sense for this to be per-cpu? > >> > >> It's probably better to either just make it __read_mostly or get the > >> static branches that folks were suggesting actually working. > > > > I still wonder if this isn't just better as a boot command line > > It's simpler that way. But, ideally, we want to make it runtime > switchable to match the implementation in the distros.
Stop this silly argument please. The distros shipped lots of crap which we dont want to have at all. I told you folks yesterday what I want to see and the sysctl thing is the least on that list and it's not needed for getting the important thing - the protection - to work. Can we pretty please do the basics and worry about that sysctl or whatever people have on their wishlist once the dust settled. Thanks, tglx