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