Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753854AbaFRRdo (ORCPT ); Wed, 18 Jun 2014 13:33:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:29924 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbaFRRdn (ORCPT ); Wed, 18 Jun 2014 13:33:43 -0400 From: Bandan Das To: Paolo Bonzini Cc: Nadav Amit , gleb@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, joro@8bytes.org Subject: Re: [PATCH 3/3] KVM: x86: correct mwait and monitor emulation References: <1403101176-23664-1-git-send-email-namit@cs.technion.ac.il> <1403101176-23664-4-git-send-email-namit@cs.technion.ac.il> <53A1C1F2.4010909@redhat.com> Date: Wed, 18 Jun 2014 13:33:27 -0400 In-Reply-To: <53A1C1F2.4010909@redhat.com> (Paolo Bonzini's message of "Wed, 18 Jun 2014 18:44:34 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo Bonzini writes: > Il 18/06/2014 18:43, Bandan Das ha scritto: >>> > mwait and monitor are currently handled as nop. Considering this behavior, they >>> > should still be handled correctly, i.e., check execution conditions and generate >>> > exceptions when required. mwait and monitor may also be executed in real-mode >> Is this necessary ? They are NOPs and kvm prints that out (correctly so) to dmesg. >> Implementing them correctly is a different thing, but adding extra checks for NOPs >> just seems like adding extra cycles. > > Raising the correct exception is a good thing, though. The guest is > going to busy wait anyway, it doesn't matter how fast it does that. :) Thanks, makes sense. I was also thinking why to advertise it at all, but it's probably more common than I think it is. > Paolo > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/