On 3 November 2021 12:35:11 GMT, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >On 11/3/21 10:47, David Woodhouse wrote: >> Sorry, it took me a while to realise that by "above comment" you mean >> the original commit comment (which you want me to reword) instead of >> just what I'd said in my previous email. How about this version? If >> it's OK like this then I can resubmit later today when I get back to >> a proper keyboard. > >No need to resubmit, thanks! I'll review the code later and decide >whether to include this in 5.16 or go for the "good" solution in 5.16 >and submit this one for 5.15 only. I would call this the good solution for steal time. We really do always have a userspace HVA for that when it matters, and we should use it. For Xen event channel delivery we have to do it from hardware interrupts under arbitrary current->mm and we need a kernel mapping, and we need the MMU notifiers and all that stuff. But for every mapping we do that way, we need extra checks in the MMU notifiers. For steal time there's just no need. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
