From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40772) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUaDW-0003Q3-Oj for qemu-devel@nongnu.org; Fri, 20 Jan 2017 09:31:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cUaDS-00059K-R1 for qemu-devel@nongnu.org; Fri, 20 Jan 2017 09:31:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41584) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cUaDS-00058h-LG for qemu-devel@nongnu.org; Fri, 20 Jan 2017 09:30:58 -0500 References: <20170117010204.4909-1-ehabkost@redhat.com> <309bd499-204d-df07-aa99-9a999cfecabc@linux.vnet.ibm.com> <20170118170049.GB3491@thinpad.lan.raisama.net> <45e82b29-1ebe-3f34-0cc1-35d60c6044da@linux.vnet.ibm.com> <20170118173406.GF3491@thinpad.lan.raisama.net> <20170119104837.GL3491@thinpad.lan.raisama.net> <20170119174559.GI16641@redhat.com> From: David Hildenbrand Message-ID: Date: Fri, 20 Jan 2017 15:30:54 +0100 MIME-Version: 1.0 In-Reply-To: <20170119174559.GI16641@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [libvirt] [PATCH 0/9] i386: query-cpu-model-expansion test script List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Eduardo Habkost , libvir-list@redhat.com, qemu-devel@nongnu.org, Christian Borntraeger , "Collin L. Walling" , "Jason J. Herne" , Cornelia Huck , Igor Mammedov , Jiri Denemark , Richard Henderson Am 19.01.2017 um 18:45 schrieb Daniel P. Berrange: > On Thu, Jan 19, 2017 at 06:21:22PM +0100, David Hildenbrand wrote: >> >>>> Also think about "query-cpu-model-expansion model=host type=static", >>>> which will primarily be used by libvirt on s390x. There is no way to >>>> expand this into a static cpu model. Faking anything will just hide errors. >>> >>> Yes, static expansion of host model must always return an error >>> if it's not possible to expand. >>> >>>> >>>> If "host" can't be expanded, QEMU has to be treated like there is no CPU >>>> model support (as for older QEMU versions). >>> >>> OK. I will propose a patch updating the query-cpu-model-expansion >>> documentation to be more explicit about it. >> >> The only real alternative I see would be disabling the query-cpu-model-* >> interface completely if KVM support is not available. >> >> This would however mean, that the same QEMU binary would have the >> interface when running under TCG, but not when running under KVM on an >> old KVM version. >> >> That also doesn't really feel right, or what do you think? > > Yeah that really isn't good. query-cpu-model-* needs to work on TCG > and *not* have a dependancy on KVM in that case, since you can be > running TCG s390 on a x86_64 host, so the host CPU is totally irrelevant > for TCG > Actually what I meant was: TCG: query-cpu-model-* interface always provided KVM (with cpu model support): query-cpu-model-* interface provided KVM (without cpu model support): no query-cpu-model-* interface provided This would avoid having to report an error when expanding "host" in the third case (KVM without cpu model support) but would lead to one QEMU binary having a different set of supported qmp calls when called from TCG and KVM. > Regards, > Daniel > -- David