On Wed, Nov 23, 2016 at 05:24:55PM +0100, Jan Kiszka wrote: > > On 11/23/2016 03:46 PM, Mark Rutland wrote: > >> I think jailhouse needs to gain some PSCI_CPU_SUSPEND support. It should > >> be able to at least use WFI safely, and ideally it would call into the > >> real PSCI implementation for deeper states. > > Good point! wfi would be simple and safe, but is going into deeper > states side-effect free for other cores? That's always the major concern > about power saving, not only on ARM...
In platform coordinated mode, it *should* be side-effect free for otehr cores per the spec. The idle states requested by CPUs are treated as a vote; the implementation must respect the shallowest idle state requested and go no deeper, so resources shouldn't be reset unexpectedly. In OS initiated mode, that's not the case, and the last core standing can override previous votes. It should be possible to inhibit that, however. We can transition the root cell back to platform coordinated mode and never expose OS initiated mode to other inmates, or jailhouse could reject/restrict calls that would violate cross-inmate expectations. Thanks, Mark. -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
