From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:49407) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7qXC-0004gh-00 for qemu-devel@nongnu.org; Wed, 14 Mar 2012 11:55:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S7qWn-0000WP-9L for qemu-devel@nongnu.org; Wed, 14 Mar 2012 11:54:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44814) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S7qWn-0000WH-17 for qemu-devel@nongnu.org; Wed, 14 Mar 2012 11:54:17 -0400 Date: Wed, 14 Mar 2012 17:54:09 +0200 From: Gleb Natapov Message-ID: <20120314155409.GI2304@redhat.com> References: <4F3CFBBB.5020600@codemonkey.ws> <4F5F141F.8080202@cn.fujitsu.com> <4F5F29CE.70806@suse.de> <4F604FF9.8010403@cn.fujitsu.com> <4F6058BE.4060403@redhat.com> <20120314134959.GC14227@dhcp-192-168-178-175.profitbricks.localdomain> <20120314152324.GF2304@redhat.com> <4F60BA15.90506@codemonkey.ws> <20120314153529.GG2304@redhat.com> <4F60BC7A.9000504@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F60BC7A.9000504@codemonkey.ws> Subject: Re: [Qemu-devel] [PATCH 2/7] Convert pc cpu to qdev List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Lai Jiangshan , Jan Kiszka , "qemu-devel@nongnu.org" , Vasilis Liaskovitis , Igor Mammedov , Andreas =?utf-8?Q?F=C3=A4rber?= On Wed, Mar 14, 2012 at 10:42:50AM -0500, Anthony Liguori wrote: > On 03/14/2012 10:35 AM, Gleb Natapov wrote: > >On Wed, Mar 14, 2012 at 10:32:37AM -0500, Anthony Liguori wrote: > >>On 03/14/2012 10:23 AM, Gleb Natapov wrote: > >>>On Wed, Mar 14, 2012 at 02:49:59PM +0100, Vasilis Liaskovitis wrote: > >>>>Hi, > >>>> > >>>>On Wed, Mar 14, 2012 at 09:37:18AM +0100, Igor Mammedov wrote: > >>>>>On 03/14/2012 08:59 AM, Lai Jiangshan wrote: > >>>>>>not accepted, so I don't know how to take part in. > >>>>> > >>>>>As I see it, there is not much to do from cpu hot-plug perspective. > >>>>>It's just a matter of adaptation QOM-ified cpus for usage from > >>>>>qdev device_add, and I'm working on it. > >>>>>However, there is a lot to be done in cpu unplug area: > >>>>> - host side: there is unaccepted patches to destroy vcpu > >>>>> during VM-lifecycle. They are still need to be worked on: > >>>>> "[Qemu-devel] [PATCH 0] A series patches for kvm&qemu to enable vcpu destruction in kvm" > >>>>> - linux guest side: kernel can receive ACPI request to unplug cpu, > >>>>> but does nothing with it (last time I've tested it with 3.2 kernel), > >>>>> You might wish to look at following mail threads: > >>>>> https://lkml.org/lkml/2011/9/30/18 > >>>>> http://lists.gnu.org/archive/html/qemu-devel/2011-10/msg02254.html > >>>> > >>>>I also plan to resubmit the qemu-side of ACPI cpu unplug request: > >>>>http://lists.nongnu.org/archive/html/qemu-devel/2012-01/msg03037.html > >>>>so that they work independently of the "host side" patches mentioned above. > >>>> > >>>>It would be great for the QOMify/hotplug/icc patches to be accepted soon, > >>>>since this would make unplug testing/development more straightoward. > >>>> > >>>On a different note, are your going to continue working on your memory hot plug series? > >>>I am going to look at it now. > >> > >>Memory hotplug.. that's going to be fun :-) > >> > >Why? What fundamental difficultly do you anticipate? > > There's still a few places in QEMU that assume that > qemu_ram_get_ptr() returns a pointer that's good indefinitely. > > We also don't have a mechanism to revoke cpu_physical_map() > pointers. Maybe the answer is reference counting and relying on > being able to eventually release the memory... Of course, then an > unplug followed by an immediate plug would be complicated. > Hmm, Avi assured me that with the memory API rework it should be easy :( grep founds nothing about qemu_ram_get_ptr() and cpu_physical_map() though. What should I look for? > Hot add should be easy, hot remove will be pretty hard I think. > > Regards, > > Anthony Liguori > > > > >-- > > Gleb. -- Gleb.