> On Apr 26, 2021, at 7:51 AM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote: > > >> >>> The original code "int $2" can provide the needed CPU-hidden-NMI-masked >>> when entering #NMI, but I doubt it about this change. >> >> How would "int $2" block NMIs? The hidden effect of this change (and I >> should have reviewed better the effect on the NMI entry code) is that the >> call will not use the IST anymore. > > My understanding is that int $2 does not block NMIs. > > So reentries might have been possible. > The C NMI code has its own reentrancy protection and has for years. It should work fine for this use case. > -Andi
