From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520Ab1LUKfz (ORCPT ); Wed, 21 Dec 2011 05:35:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35768 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752363Ab1LUKfw (ORCPT ); Wed, 21 Dec 2011 05:35:52 -0500 Message-ID: <4EF1B67D.7010603@redhat.com> Date: Wed, 21 Dec 2011 12:35:41 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 MIME-Version: 1.0 To: Jan Kiszka CC: Linus Torvalds , Alexey Zaytsev , "Liu, Jinsong" , Kernel development list , Marcelo Tosatti , "Garrett D'Amore" , kvm Subject: Re: [PATCH v2] KVM: x86: Prevent exposing TSC deadline timer feature in the absence of in-kernel APIC References: <4EF1146D.208@siemens.com> <4EF1B081.3010109@siemens.com> <4EF1B423.8050707@siemens.com> In-Reply-To: <4EF1B423.8050707@siemens.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/21/2011 12:25 PM, Jan Kiszka wrote: > We must not report the TSC deadline timer feature on our own when user > space provides the APIC as we have no clue about its features. We must not report the TSC deadline timer feature on our own, period. We should just update the timer mode mask there. Don't know how this slipped through review. I think your original idea was correct. Add a new KVM_CAP for the tsc deadline timer. Userspace can add the bit to cpuid if either it implements the feature in a userspace apic, or if it finds the new capability and uses the kernel apic. -- error compiling committee.c: too many arguments to function