On Apr 6, 2020, at 1:25 PM, Peter Zijlstra peterz@infradead.org wrote:
On Mon, Apr 06, 2020 at 03:09:51PM -0400, Vivek Goyal wrote:
On Mon, Mar 09, 2020 at 09:22:15PM +0100, Peter Zijlstra wrote: 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.
It will be nice if we can retain KVM_ASYNC_PF_SEND_ALWAYS. I have another use case outside CONFIG_PREEMPT.
I am trying to extend async pf interface to also report page fault errors to the guest.
Then please start over and design a sane ParaVirt Fault interface. The current one is utter crap.
Agreed. Don’t extend the current mechanism. Replace it.
I would be happy to review a replacement. I’m not really excited to review an extension of the current mess. The current thing is barely, if at all, correct.