[RFC PATCH 2/2] ARM: SMP support for mach-virt

[Will Deacon]

On Tue, Dec 11, 2012 at 04:34:27PM +0000, Stefano Stabellini wrote:
> On Tue, 11 Dec 2012, Will Deacon wrote:
> > On Tue, Dec 11, 2012 at 04:04:20PM +0000, Stefano Stabellini wrote:
> > > Hi!
> > 
> > Hi Stefano,
> > 
> > > Sorry for taking so long to reply but I admit I missed the thread
> > > entirely until now. I would appreciate if you could CC
> > > xen-devel at lists.xen.org and/or me for virtualization related
> > > discussions.
> > 
> > I did CC xen-arm at lists.xen.org,
>   
> Thanks!
> I don't know why I didn't receive it then :-\
> 
> In any case xen-devel is the right place for upstream related
> discussion.
> 
> 
> > but you've dropped that list in your
> > reply...
> 
> Yeah.. that's because I didn't receive the original email and I had to
> download the mailing list archives, sorry about that.

Ok, although note that I'm now getting all of your replies twice!

> 
> > > On the Xen side there are not going to be any problems related to SMP
> > > and holding pens, because secondary CPUs only come into existence after
> > > the first CPU calls the HYPERVISOR_vcpu_op hypercall (still missing on
> > > ARM).
> > 
> > Ok. Would you be willing/able to wrap this in a PSCI interface when you do
> > add SMP support for ARM?
> 
> I grepped for PSCI in the Linux tree but I couldn't find anything.
> Also I googled for ARM PSCI and nothing of value came up. Can I find a
> doc that explains what PSCI is anywhere?

There is an initial version of the document here (requires registration):

  https://silver.arm.com/download/download.tm?pv=1303201

Note that there are some updates due to clarify things a bit in areas such
as function ID numbers and the PCS. Marc and I also plan to hack something up
in kvm/mach-virt for booting secondary CPUs.

Will