From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=34414 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Q0x8g-0007AV-KU for qemu-devel@nongnu.org; Sat, 19 Mar 2011 10:28:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Q0x8f-0007A1-Co for qemu-devel@nongnu.org; Sat, 19 Mar 2011 10:28:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59918) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q0x8f-00079k-46 for qemu-devel@nongnu.org; Sat, 19 Mar 2011 10:28:21 -0400 Date: Sat, 19 Mar 2011 16:28:14 +0200 From: Gleb Natapov Subject: Re: [Qemu-devel] Re: vcpu hotplug status Message-ID: <20110319142814.GA9072@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: William Dauchy Cc: qemu-devel@nongnu.org On Sat, Mar 19, 2011 at 12:25:38PM +0100, William Dauchy wrote: > On Wed, Mar 16, 2011 at 11:17 AM, William Dauchy wrote: > > I wanted to test vcpu hotplug. When adding a cpu I'm getting > > "qdev_create_from_info: Assertion `bus->allow_hotplug' failed." > > I went through a discussion about the subject here > > http://lists.nongnu.org/archive/html/qemu-devel/2010-08/msg00999.html > > To make sure whether it was working, I hard-coded "allow_hotplug = 1"; > > the guest is now able to have more vpcus without any trouble (removing > > vcpus did not seem to work though). > > Since it definitively not a solution, I wanted to have a status about > > the subject or if I was missing something in my configuration since it > > works with a dirty workaround. > > I would be also pleased to get some tips to fix the code. > > Any thoughts? Or perhaps my message was lost among patches... > Even patches are lost among patches those days. The problem you describe is known. Both of them actually (non working vcpu remove is the second one). I am not aware of any effort to fix them. I am more concern about second problem though. bus->allow_hotplug is not fixed because of laziness on developers part, but non working vcpu remove is caused by us not understanding how cpu hot-plug works in Linux on x86. -- Gleb.