Re: [PATCH v2] x86/kvm: Disable KVM_ASYNC_PF_SEND_ALWAYS

On Mon, Mar 09, 2020 at 08:05:18PM +0100, Thomas Gleixner wrote:

Andy Lutomirski luto@kernel.org 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.