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

On Tue, Dec 11, 2012 at 04:34:27PM +0000, Stefano Stabellini wrote:

On Tue, 11 Dec 2012, Will Deacon wrote:

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On Tue, Dec 11, 2012 at 04:04:20PM +0000, Stefano Stabellini wrote:

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Hi!

Hi Stefano,

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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.

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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!

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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