Le 20/02/2024 à 09:51, Christophe Leroy a écrit : > > > Le 19/12/2023 à 07:33, Michael Ellerman a écrit : >> Aneesh Kumar K.V <aneesh.ku...@kernel.org> writes: >>> Luming Yu <luming...@shingroup.cn> writes: >>> >>>> Before we have powerpc to use the generic entry infrastructure, >>>> the call to fire user return notifier is made temporarily in powerpc >>>> entry code. >>>> >>> >>> It is still not clear what will be registered as user return notifier. >>> Can you summarize that here? >> >> fire_user_return_notifiers() is defined in kernel/user-return-notifier.c >> >> That's built when CONFIG_USER_RETURN_NOTIFIER=y. >> >> That is not user selectable, it's only enabled by: >> >> arch/x86/kvm/Kconfig: select USER_RETURN_NOTIFIER >> >> So it looks to me like (currently) it's always a nop and does nothing. >> >> Which makes me wonder what the point of wiring this feature up is :) >> Maybe it's needed for some other feature I don't know about? >> >> Arguably we could just enable it because we can, and it currently does >> nothing so it's unlikely to break anything. But that also makes it >> impossible to test the implementation is correct, and runs the risk that >> one day in the future when it does get enabled only then do we discover >> it doesn't work. > > Opened an "issue" for the day we need it: > https://github.com/KSPP/linux/issues/348
Correct one is https://github.com/linuxppc/issues/issues/477
