From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60444) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXUhI-0004UT-Em for qemu-devel@nongnu.org; Wed, 10 Aug 2016 10:41:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bXUhF-0002sP-ML for qemu-devel@nongnu.org; Wed, 10 Aug 2016 10:41:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:12998 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bXUhF-0002sF-GO for qemu-devel@nongnu.org; Wed, 10 Aug 2016 10:41:29 -0400 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u7AEepHJ101380 for ; Wed, 10 Aug 2016 10:41:28 -0400 Received: from e23smtp04.au.ibm.com (e23smtp04.au.ibm.com [202.81.31.146]) by mx0b-001b2d01.pphosted.com with ESMTP id 24qm9qsve0-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 10 Aug 2016 10:41:28 -0400 Received: from localhost by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 11 Aug 2016 00:41:25 +1000 Date: Wed, 10 Aug 2016 20:11:16 +0530 From: Bharata B Rao Reply-To: bharata@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Message-Id: <20160810144116.GA4514@in.ibm.com> Subject: [Qemu-devel] spapr: CPU compat option works only with -global for pseries-2.7 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, david@gibson.dropbear.id.au, groug@kaod.org, thuth@redhat.com, abologna@redhat.com, imammedo@redhat.com, ehabkost@redhat.com, sbhat@linux.vnet.ibm.com Hi, With CPU core hotplug support in pseries-2.7, we will have to specify the compat type using -global only as we don't yet take care of parsing -cpu cputype,compat=. There have been patches to support that: sPAPR specific one: https://lists.nongnu.org/archive/html/qemu-devel/2016-06/msg07564.html PPC generic one: https://lists.gnu.org/archive/html/qemu-devel/2016-07/msg02676.html but the patch isn't upstream yet. The result is that instead of specifying -cpu host,compat=power7 for pseries-2.7, we will have to use -cpu host -global driver=host-powerpc64-cpu,property=compat,value=power7 This behaviour is specific to pseries-2.7 and for earlier machine types the original way of specifying compat with -cpu works. Will this be a concern for libvirt ? Would it be difficult for libvirt to switch to -global when generating QEMU cmdline for compat mode for pseries-2.7 machine. Or, should we just include one of the above patches so that -cpu cputype,compat= continues to work for peseries-2.7 ? Regards, Bharata.