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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: quintela@redhat.com,
	qemu-develQEMU Developer <qemu-devel@nongnu.org>,
	KVM devel mailing list <kvm@vger.kernel.org>
Cc: "Andreas Färber" <afaerber@suse.de>,
	"Bharata B Rao" <bharata@linux.vnet.ibm.com>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Matthew Rosato" <mjrosato@linux.vnet.ibm.com>,
	"David Hildenbrand" <dahi@linux.vnet.ibm.com>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Paul Mackerras" <paulus@samba.org>
Subject: Re: KVM call for agenda for 2016-02-16
Date: Tue, 16 Feb 2016 12:54:57 +0100	[thread overview]
Message-ID: <56C30E11.8040606@de.ibm.com> (raw)
In-Reply-To: <871t8kpo6j.fsf@emacs.mitica>

So my quick and dirty summary of CPU as _I_ understand it
(and I only have some part time bandwidth at the moment for that)

x86 has cpu hotplug. Some history
qemu-kvm had cpu_set in the past
qemu has cpu_add for a while now
libvirt code uses cpu_add cross-platform out of the box

proposal to use device_add. Currently this has the following issues that
we need to discuss:
- will require capability checking and dual code in libvirt (and libvirt updates)
- Power has some constraints that are hard to model with just device add
	- David Gibson proposes a two layer interface
		- low level: device add cpu-package
		- high level
- David Hildenbrand has some concerns regarding CPU models (with base model + feature
  on/off), as device_add needs instantiatable type
- devel_del: s390 has no interface for cpu removal (Matts latest patches reset the 
machine just like z/VM - until we have some interface)
- anything else? (cpu hotplug on ARM or MIPS?)

Would be good to use todays call to have a plan how to finish things soon.
(maybe even for 2.6)

Christian 



  parent reply	other threads:[~2016-02-16 11:55 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-10 15:42 KVH call for agenda for 2016-02-16 Juan Quintela
2016-02-10 15:48 ` Christian Borntraeger
2016-02-12 17:28   ` Andreas Färber
2016-02-16 11:54 ` Christian Borntraeger [this message]
2016-02-17 20:40   ` KVM " Eduardo Habkost
2016-02-17 22:51     ` Juan Quintela
2016-02-22 19:02       ` [Qemu-devel] " Thomas Huth
2016-02-23  9:59         ` Juan Quintela

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