On Wed, Dec 18, 2013 at 12:25 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > On Wed, Dec 18 2013 at 06:18:54 PM, Anup Patel <anup@xxxxxxxxxxxxxx> wrote: >> On Wed, Dec 18, 2013 at 11:41 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: >>> On Wed, Dec 18 2013 at 03:52:29 PM, Anup Patel <anup@xxxxxxxxxxxxxx> wrote: >>>> On Wed, Dec 18, 2013 at 9:11 PM, Marc Zyngier <marc.zyngier@xxxxxxx> 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) >>>> >>>> Does this mean we should have first isolate v0.2 ID range >>>> from v0.1 ID range? >>> >>> Yes. >> >> Are you planning to do it ? >> OR >> Do you expect me to do it because this patchset would depend on that? > > First, I want to understand the objections that were raised against > using the Function IDs as defined in the spec. > > Then, assuming we move in that direction, I'd expect you to create a > separate range of IDs and update the PSCI code to handle both PSCI > versions. > > But as this has direct implication with userspace (DT generation), I'd > rather take it slow and first try to understand the issues Mark raised. Here is the thread where relying on SMC calling convention was discussed: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-July/188057.html Rob _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
