From: Marc Zyngier <marc.zyngier@arm.com>
To: David Hildenbrand <david@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>,
Igor Mammedov <imammedo@redhat.com>
Cc: Christoffer Dall <cdall@cs.columbia.edu>,
Christoffer Dall <christofferdall@christofferdall.dk>,
QEMU Developers <qemu-devel@nongnu.org>,
qemu-arm <qemu-arm@nongnu.org>,
kvmarm@lists.cs.columbia.edu
Subject: Re: [Qemu-arm] [Qemu-devel] VCPU hotplug on KVM/ARM
Date: Wed, 7 Mar 2018 12:47:39 +0000 [thread overview]
Message-ID: <acd04e77-33c9-71f1-c140-1f9c20da8022@arm.com> (raw)
In-Reply-To: <b049a501-cd5e-8c22-9c62-88c950e01b1b@redhat.com>
On 01/03/18 13:32, David Hildenbrand wrote:
> On 01.03.2018 11:05, Peter Maydell wrote:
>> On 1 March 2018 at 09:50, Igor Mammedov <imammedo@redhat.com> wrote:
>>> In QEMU on x86 (and I think ppc, s390 as well), we create vCPUs on demand.>>
>>> It would be nice if ARM would be able to do that too,
>>> so that it could take advantage of the same code.
>>
>> It's not clear to me how that would work, given that for
>> instance the interrupt controller wants to know up-front
>> how many CPUs it has to deal with.
>>
>
> So how is cpu hotplug handled in HW? Or doesn't it even exist there?
I don't know of any physical system offering that facility.
> (we have max_cpus for the interrupt controller, but not sure if that is
> what we want)
We'd need something along those lines. Each CPU has a notional point to
point link to the interrupt controller (to the redistributor, to be
precise), and this entity must pre-exist.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2018-03-07 12:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000e01d3afad$b9a13830$2ce3a890$@codeaurora.org>
[not found] ` <20180227104708.GA11391@cbox>
[not found] ` <ac329e1b1f5265a805916ab4f8708f9d@codeaurora.org>
[not found] ` <20180227124604.GA2373@cbox>
2018-02-27 13:21 ` [Qemu-arm] VCPU hotplug on KVM/ARM Andrew Jones
2018-03-01 9:50 ` [Qemu-arm] [Qemu-devel] " Igor Mammedov
2018-03-01 10:05 ` Peter Maydell
2018-03-01 13:32 ` [Qemu-devel] [Qemu-arm] " David Hildenbrand
2018-03-07 12:47 ` Marc Zyngier [this message]
2018-07-24 18:35 ` Maran Wilson
2018-07-25 6:45 ` [Qemu-devel] " Igor Mammedov
2018-07-25 10:40 ` Marc Zyngier
2018-07-25 12:28 ` [Qemu-devel] " Andrew Jones
2018-07-25 13:07 ` Marc Zyngier
2018-07-25 17:26 ` Maran Wilson
2018-07-31 10:27 ` Igor Mammedov
2018-07-31 10:57 ` David Hildenbrand
2018-08-01 8:09 ` [Qemu-arm] " Bharata B Rao
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