On Mon 2022-05-23 11:56:12, Guilherme G. Piccoli wrote: > On 19/05/2022 16:20, Scott Branden wrote: > > [...] > >> Hi Scott / Desmond, thanks for the detailed answer! Is this adapter > >> designed to run in x86 only or you have other architectures' use cases? > > The adapter may be used in any PCIe design that supports DMA. > > So it may be possible to run in arm64 servers. > >> > >> [...] > >> With that said, and given this is a lightweight notifier that ideally > >> should run ASAP, I'd keep this one in the hypervisor list. We can > >> "adjust" the semantic of this list to include lightweight notifiers that > >> reset adapters. > > Sounds the best to keep system operating as tested today. > >> > >> With that said, Petr has a point - not always such list is going to be > >> called before kdump. So, that makes me think in another idea: what if we > >> have another list, but not on panic path, but instead in the custom > >> crash_shutdown()? Drivers could add callbacks there that must execute > >> before kexec/kdump, no matter what. > > It may be beneficial for some other drivers but for our use we would > > then need to register for the panic path and the crash_shutdown path. > > We notify the VK card for 2 purposes: one to stop DMA so memory stop > > changing during a kdump. And also to get the card into a good state so > > resets happen cleanly. > > Thanks Scott! With that, I guess it's really better to keep this > notifier in this hypervisor/early list - I'm planning to do that for V2. > Unless Petr or somebody has strong feelings against that, of course. I am fine with it because we do not have a better solution at the moment. It might be a good candidate for the 5th notifier list mentioned in the thread https://lore.kernel.org/r/YoyQyHHfhIIXSX0U@alley . But I am not sure if the 5th list is worth the complexity. Best Regards, Petr
