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). -- Anup > > -- PMM > _______________________________________________ > kvmarm mailing list > kvmarm@xxxxxxxxxxxxxxxxxxxxx > https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
