From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [Qemu-devel] [PATCH 2/2] Expose tsc deadline timer cpuid to guest Date: Tue, 06 Mar 2012 11:14:55 +0100 Message-ID: <4F55E39F.6020608@siemens.com> References: <4F0482D6.8080705@web.de> <4F060961.9050002@web.de> <4F0A099C.5040805@web.de> <4F4BBAEC.2040603@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "qemu-devel@nongnu.org" , Marcelo Tosatti , Avi Kivity , kvm , Alexey Zaytsev To: "Liu, Jinsong" Return-path: Received: from goliath.siemens.de ([192.35.17.28]:26070 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758083Ab2CFKPK (ORCPT ); Tue, 6 Mar 2012 05:15:10 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 2012-03-06 08:49, Liu, Jinsong wrote: > Jan, > > Any comments? I feel some confused about your point 'disable cpuid feature for older machine types by default': are you planning a common approach for this common issue, or, you just ask me a specific solution for the tsc deadline timer case? I think a generic solution for this can be as simple as passing a feature exclusion mask to cpu_init. You could simple append a string of "-feature1,-feature2" to the cpu model that is specified on creation. And that string could be defined in the compat machine descriptions. Does this make sense? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:44148) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S4rQG-0000nY-H9 for qemu-devel@nongnu.org; Tue, 06 Mar 2012 05:15:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S4rQA-0004E2-95 for qemu-devel@nongnu.org; Tue, 06 Mar 2012 05:15:12 -0500 Received: from goliath.siemens.de ([192.35.17.28]:32757) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S4rQ9-00049r-UA for qemu-devel@nongnu.org; Tue, 06 Mar 2012 05:15:06 -0500 Message-ID: <4F55E39F.6020608@siemens.com> Date: Tue, 06 Mar 2012 11:14:55 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <4F0482D6.8080705@web.de> <4F060961.9050002@web.de> <4F0A099C.5040805@web.de> <4F4BBAEC.2040603@siemens.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 2/2] Expose tsc deadline timer cpuid to guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Liu, Jinsong" Cc: Alexey Zaytsev , Marcelo Tosatti , "qemu-devel@nongnu.org" , kvm , Avi Kivity On 2012-03-06 08:49, Liu, Jinsong wrote: > Jan, > > Any comments? I feel some confused about your point 'disable cpuid feature for older machine types by default': are you planning a common approach for this common issue, or, you just ask me a specific solution for the tsc deadline timer case? I think a generic solution for this can be as simple as passing a feature exclusion mask to cpu_init. You could simple append a string of "-feature1,-feature2" to the cpu model that is specified on creation. And that string could be defined in the compat machine descriptions. Does this make sense? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux