On Mon, Mar 09, 2020 at 08:05:18PM +0100, Thomas Gleixner wrote: > Andy Lutomirski <luto@xxxxxxxxxx> writes: > > I'm okay with the save/restore dance, I guess. It's just yet more > > entry crud to deal with architecture nastiness, except that this > > nastiness is 100% software and isn't Intel/AMD's fault. > > And we can do it in C and don't have to fiddle with it in the ASM > maze. Right; I'd still love to kill KVM_ASYNC_PF_SEND_ALWAYS though, even if we do the save/restore in do_nmi(). That is some wild brain melt. Also, AFAIK none of the distros are actually shipping a PREEMPT=y kernel anyway, so killing it shouldn't matter much. If people want to recover that, I'd suggest they sit down and create a sane paravirt interface for this.