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From: Marc Zyngier <marc.zyngier@arm.com>
To: Maran Wilson <maran.wilson@oracle.com>,
	kvmarm@lists.cs.columbia.edu, bthakur@codeaurora.org
Cc: Andrew Jones <drjones@redhat.com>,
	Christoffer Dall <cdall@kernel.org>,
	Christoffer Dall <cdall@cs.columbia.edu>,
	qemu-devel@nongnu.org,
	Christoffer Dall <christofferdall@christofferdall.dk>,
	qemu-arm@nongnu.org, imammedo@redhat.com,
	peter.maydell@linaro.org, david@redhat.com
Subject: Re: [Qemu-devel] VCPU hotplug on KVM/ARM
Date: Wed, 25 Jul 2018 11:40:54 +0100	[thread overview]
Message-ID: <74427c65-b860-d576-04f9-766253285210@arm.com> (raw)
In-Reply-To: <b589d714-4f12-e450-7ca5-e55fed4d1705@oracle.com>

On 24/07/18 19:35, Maran Wilson wrote:
> It's been a few months since this email thread died off. Has anyone 
> started working on a potential solution that would allow VCPU hotplug on 
> KVM/ARM ? Or is this a project that is still waiting for an owner who 
> has the time and inclination to get started?

This is typically a project for someone who would have this particular
itch to scratch, and who has a demonstrable need for this functionality.

Work wise, it would have to include adding physical CPU hotplug support
to the arm64 kernel as a precondition, before worrying about doing it in
KVM.

For KVM itself, particular area of interests would be:
- Making GICv3 redistributors magically appear in the IPA space
- Live resizing of GICv3 structures
- Dynamic allocation of MPIDR, and mapping with vcpu_id

This should keep someone busy for a good couple of weeks (give or take a
few months).

That being said, I'd rather see support in QEMU first, creating all the
vcpu/redistributors upfront, and signalling the hotplug event via the
virtual firmware. And then post some numbers to show that creating all
the vcpus upfront is not acceptable.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <marc.zyngier@arm.com>
To: Maran Wilson <maran.wilson@oracle.com>,
	kvmarm@lists.cs.columbia.edu, bthakur@codeaurora.org
Cc: Christoffer Dall <cdall@cs.columbia.edu>,
	Christoffer Dall <cdall@kernel.org>,
	david@redhat.com, qemu-devel@nongnu.org,
	Christoffer Dall <christofferdall@christofferdall.dk>,
	qemu-arm@nongnu.org, imammedo@redhat.com
Subject: Re: VCPU hotplug on KVM/ARM
Date: Wed, 25 Jul 2018 11:40:54 +0100	[thread overview]
Message-ID: <74427c65-b860-d576-04f9-766253285210@arm.com> (raw)
In-Reply-To: <b589d714-4f12-e450-7ca5-e55fed4d1705@oracle.com>

On 24/07/18 19:35, Maran Wilson wrote:
> It's been a few months since this email thread died off. Has anyone 
> started working on a potential solution that would allow VCPU hotplug on 
> KVM/ARM ? Or is this a project that is still waiting for an owner who 
> has the time and inclination to get started?

This is typically a project for someone who would have this particular
itch to scratch, and who has a demonstrable need for this functionality.

Work wise, it would have to include adding physical CPU hotplug support
to the arm64 kernel as a precondition, before worrying about doing it in
KVM.

For KVM itself, particular area of interests would be:
- Making GICv3 redistributors magically appear in the IPA space
- Live resizing of GICv3 structures
- Dynamic allocation of MPIDR, and mapping with vcpu_id

This should keep someone busy for a good couple of weeks (give or take a
few months).

That being said, I'd rather see support in QEMU first, creating all the
vcpu/redistributors upfront, and signalling the hotplug event via the
virtual firmware. And then post some numbers to show that creating all
the vcpus upfront is not acceptable.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

  parent reply	other threads:[~2018-07-25 10:41 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-27  9:31 VCPU hotplug on KVM/ARM bthakur
2018-02-27 10:47 ` Christoffer Dall
2018-02-27 12:04   ` bthakur
2018-02-27 12:46     ` Christoffer Dall
2018-02-27 13:21       ` [Qemu-devel] " Andrew Jones
2018-02-27 13:21         ` Andrew Jones
2018-03-01  9:50         ` [Qemu-devel] " Igor Mammedov
2018-03-01  9:50           ` Igor Mammedov
2018-03-01 10:05           ` [Qemu-devel] [Qemu-arm] " Peter Maydell
2018-03-01 10:05             ` [Qemu-arm] [Qemu-devel] " Peter Maydell
2018-03-01 13:32             ` [Qemu-devel] [Qemu-arm] " David Hildenbrand
2018-03-01 13:32               ` David Hildenbrand
2018-03-07 12:47               ` Marc Zyngier
2018-03-07 12:47                 ` Marc Zyngier
2018-07-24 18:35         ` [Qemu-devel] " Maran Wilson
2018-07-24 18:35           ` Maran Wilson
2018-07-25  6:45           ` [Qemu-devel] " Igor Mammedov
2018-07-25  6:45             ` Igor Mammedov
2018-07-25 10:40           ` Marc Zyngier [this message]
2018-07-25 10:40             ` Marc Zyngier
2018-07-25 12:28             ` [Qemu-devel] " Andrew Jones
2018-07-25 12:28               ` Andrew Jones
2018-07-25 13:07               ` Marc Zyngier
2018-07-25 13:07                 ` Marc Zyngier
2018-07-25 17:26                 ` Maran Wilson
2018-07-25 17:26                   ` Maran Wilson
2018-07-31 10:27                 ` Igor Mammedov
2018-07-31 10:27                   ` Igor Mammedov
2018-07-31 10:57                   ` David Hildenbrand
2018-07-31 10:57                     ` David Hildenbrand
2018-08-01  8:09                   ` Bharata B Rao
2018-08-01  8:09                     ` Bharata B Rao

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