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Date: Thu, 25 Jun 2015 14:41:13 +0200
From: Christoffer Dall <christoffer.dall@linaro.org>
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Subject: Re: [Qemu-devel] should KVM or userspace be the one which decides
 what MIPIDR/affinity values to assign to vcpus?
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>, Shlomo Pongratz <shlomo.pongratz@huawei.com>, Shlomo Pongratz <shlomopongratz@gmail.com>, Pavel Fedin <p.fedin@samsung.com>, QEMU Developers <qemu-devel@nongnu.org>, Shannon Zhao <shannon.zhao@linaro.org>, Ashok Kumar <ashoks@broadcom.com>, Igor Mammedov <imammedo@redhat.com>, "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>

On Thu, Jun 25, 2015 at 10:06:20AM +0100, Peter Maydell wrote:
> On 25 June 2015 at 09:00, Christoffer Dall <christoffer.dall@linaro.org> wrote:
> > Of course, KVM can deny an unsupported configuration, but I am wondering
> > if we really think anybody will care about the 'model such specific
> > hardware' aspect with KVM, or if we should only consider the 'I want a
> > VM with x VCPUs' scenario, in which case the second option below seems
> > simpler to me.
> 
> I agree it's not very likely anybody cares about the specific cluster
> topology. However if we don't want to support arbitrary topologies
> then QEMU is going to end up in the business of editing the user
> supplied device tree blob to make its cpu definitions match up with
> whatever the kernel provides, which could be pretty tedious.
> 
I see, then you can't easily contruct a machine and a DT in one go
before talking to KVM.

Oh well, I don't feel strongly one way or the other.

-Christoffer