Re: [PATCH 15/24] x86/mm: Allow flushing for future ASID switches

[Peter Zijlstra]

On Tue, Nov 28, 2017 at 08:05:05PM +0100, Peter Zijlstra wrote:
> I'm now staring at the RESTORE_CR3 stuff, and that appears to be called
> in the NMI handling where the stack is not to be used (if I read it
> right), so that's going to be a little more tricky.

As I just mentioned on IRC; I just realized that RESTORE_CR3 is always
flushing. So what I just wrote is effectively an optimization that
allows a nonflush.