On Wed, Dec 18, 2013 at 03:41:27PM +0000, Marc Zyngier wrote: > Hi Anup, > > On Wed, Dec 18 2013 at 03:03:43 PM, Anup Patel <anup@xxxxxxxxxxxxxx> wrote: > > On Wed, Dec 18, 2013 at 8:08 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > >> Christoffer Dall <christoffer.dall@xxxxxxxxxx> writes: > >> > >>> On Tue, Dec 17, 2013 at 05:05:34PM +0530, Anup Patel wrote: > >>>> The Power State and Coordination Interface (PSCI) specification defines > >>>> SYSTEM_OFF and SYSTEM_RESET functions for system poweroff and reboot. > >>>> > >>>> This patchset adds emulation of PSCI SYSTEM_OFF and SYSTEM_RESET functions > >>>> in KVM ARM/ARM64 by forwarding them to user space (QEMU or KVMTOOL) using > >>>> KVM_EXIT_SYSTEM_EVENT exit reason. > >>>> > >>>> To try this patch from guest kernel, we will need PSCI-based restart and > >>>> poweroff support in the guest kenel for both ARM and ARM64. > >>>> > >>>> Rob Herring has already submitted patches for PSCI-based restart and > >>>> poweroff in ARM kernel but these are not merged yet due unstable device > >>>> tree bindings of kernel PSCI support. We will be having similar patches > >>>> for PSCI-based restart and poweroff in ARM64 kernel. > >>>> (Refer http://www.spinics.net/lists/arm-kernel/msg262217.html) > >>>> (Refer http://www.spinics.net/lists/devicetree/msg05348.html) > >>> > >>> Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> > >>> > >>> I can merge this series if Marc acks it as well. > >> > >> The patches themselves are mostly fine. One issue though: They implement > >> part of the v0.2 spec, but keep on using the range of function IDs that > >> we made up for v0.1. > >> > >> I just had a chat with the person responsible for the spec, and realized > >> that the Function IDs mentionned in the v0.2 spec are not optional, and > >> not using them would be in direct violation of the spec (the new numbers > >> now come directly from the SMC calling convention). > > > > Should we emulate PSCI_VERSION call to help Guest determine > > the spec version emulated by KVM (i.e. v0.1 or v0.2) ?? > > I think that'd be a nice to have, but the guest is likely to get its > information from the DT anyway. Plus I don't think the original PSCI > spec specified PSCI_VERSION, which only make it useful for whatever > comes after v0.2. > > So I think we need to: > - Use the new range for PSCI v0.2 (while still supporting v0.1 and the > old range) > - Get the kernel and DT bindings into shape > - Merge all of that at the same time > Don't we also need a way for user space to tell KVM if it should emulate v0.1 or v0.2 of PSCI so we don't break backwards compatibility with tools that spit out a device tree and use guest kernels based on v0.1? This could be a new feature for KVM_ARM_VCPU_INIT, but perhaps it should be something on the VM level, hmmm. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
