Messages in this thread | | | Date | Fri, 29 Mar 2013 13:53:35 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [PATCH v4 2/2] arm: prefer PSCI for SMP bringup |
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On Fri, 29 Mar 2013, Stefano Stabellini wrote:
> On Fri, 29 Mar 2013, Nicolas Pitre wrote: > > On Fri, 29 Mar 2013, Stefano Stabellini wrote: > > > > > If PSCI initializes correctly and PSCI SMP operations are available, use them. > > > This is required for SMP support in Dom0 on Xen. > > > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > CC: will.deacon@arm.com > > > CC: arnd@arndb.de > > > CC: marc.zyngier@arm.com > > > CC: linux@arm.linux.org.uk > > > CC: nico@linaro.org > > > > I'd suggest you also include in your series the patch I posted earlier > > providing a runtime mdesc->smp_init method as well. > > OK. > > > > This way the > > priority order would be: > > > > - If mdesc->smp_init is non null then use that. > > > > - Otherwise, if PSCI is available then use that. > > > > - Otherwise use mdesc->smp. > > > > This way, if the PSCI default has to be overriden (like in the MCPM case > > because it needs to wrap PSCI itself, or to cover Rob's concern) then > > this can be achieved at run time on a per mdesc basis. > > Actually that's not a bad idea, it could make everybody happy. > What about the following, in this precise order: > > - if a xen hypervisor node is present on device tree, use PSCI; > - otherwise if mdesc->smp_init is non null then use it; > - otherwise if PSCI is available then use it; > - otherwise use mdesc->smp. > > It's the most practical solution to satisfy everybody's needs.
Maybe I'm missing something obvious, but why can't xen declare a mdesc of its own? Given it is going to tweak the DT passed to the kernel anyway that shouldn't be a problem.
That would be more eleguant than adding xen exception hooks in generic code.
Nicolas
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