On 17/10/13 12:07, Anup Patel wrote: > On Thu, Oct 17, 2013 at 2:40 PM, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote: >> On 17 October 2013 09:37, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>> On 16/10/13 18:02, Anup Patel wrote: >>>> The PSCI SYSTEM_OFF and SYSTEM_RESET functions are VM or Guest level >>>> functions hence cannot be emulated by the in-kernel PSCI emulation code. >>> >>> Why can't we implement system-wide functionality in the kernel? I fail >>> to see the issue here. >> >> Because the kernel isn't emulating the whole board, and you need >> to power off or reset the whole board, not just the CPUs. >> >>> I'm really not keen on this approach. Having part of the PSCI >>> implementation offloaded to userspace means we don't have a complete >>> implementation in KVM anymore, and we end-up duplicating functionality >>> all over the place. >>> >>> Also, OFF and RESET are not PSCI specific concepts, and could be >>> implemented in various ways. I'm more inclined to return a >>> *standardized* exit code that the various platforms can interpret. >> >> Maybe we should have a more generic "kernel can't handle this, >> toss it to userspace" API? That might also fit in with supporting >> guests that want to make SMC calls to an emulated monitor... > > Excatly, that is what this patch does by forwarding PSCI SYSTEM_OFF > and SYSTEM_RESET to user space (QEMU or KVMTOOL). I think you missed the words standardized and generic above. M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
