From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53539) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1drlem-0002IC-JD for qemu-devel@nongnu.org; Tue, 12 Sep 2017 09:55:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1drleg-00078B-Qy for qemu-devel@nongnu.org; Tue, 12 Sep 2017 09:55:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38552) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1drleg-00077M-Kn for qemu-devel@nongnu.org; Tue, 12 Sep 2017 09:55:10 -0400 Date: Tue, 12 Sep 2017 15:55:02 +0200 From: Igor Mammedov Message-ID: <20170912155502.5ee2d753@nial.brq.redhat.com> In-Reply-To: <20170911152150.12535-1-david@redhat.com> References: <20170911152150.12535-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 00/21] s390x cleanups and CPU hotplug via device_add List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Hildenbrand Cc: qemu-devel@nongnu.org, Matthew Rosato , thuth@redhat.com, Eduardo Habkost , cohuck@redhat.com, Richard Henderson , Alexander Graf , Markus Armbruster , borntraeger@de.ibm.com, Paolo Bonzini On Mon, 11 Sep 2017 17:21:29 +0200 David Hildenbrand wrote: > The first patches are a bunch of cleanups. I decided to go the > extra mile and implement CPU hotplug via "device_add", as well as > "query-hotpluggable-cpus". > > On s390x, only complete cores can be plugged. CPU hot unplug is currently > not supported by the architecture. > > Support for hotplugging CPUs in random core-id order (last two patches) > is added. We once hat a KVM bug preventing this, but the stable patch > should now be included in relevant places - 152e9f65d66f ("KVM: s390: fix > wrong lookup of VCPUs by array index"). Current tooling will plug them in > sequential order anyway, so it should not hurt. do you plan to convert hw/s390x/s390-virtio.c machine to possible_cpus as well? it's not necessary to enable hotplug on it but sharing code and initializing cpus the same way would be plus. [...]