From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/2] KVM: x86 emulator: don't update vcpu state if instruction is restarted. Date: Sun, 01 Aug 2010 15:35:41 +0300 Message-ID: <4C556A1D.2050105@redhat.com> References: <1280405513-579-2-git-send-email-gleb@redhat.com> <4C545C79.1010102@redhat.com> <20100801082815.GC24773@redhat.com> <4C55364E.9090605@redhat.com> <20100801090145.GD24773@redhat.com> <4C553B00.8030100@redhat.com> <20100801092438.GE24773@redhat.com> <4C5545AB.3080806@redhat.com> <20100801105337.GF24773@redhat.com> <4C5565C6.1090004@redhat.com> <20100801122316.GG24773@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46443 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755045Ab0HAMfn (ORCPT ); Sun, 1 Aug 2010 08:35:43 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o71CZguF025533 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 1 Aug 2010 08:35:43 -0400 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by int-mx05.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o71CZgMq019085 for ; Sun, 1 Aug 2010 08:35:42 -0400 In-Reply-To: <20100801122316.GG24773@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/01/2010 03:23 PM, Gleb Natapov wrote: > On Sun, Aug 01, 2010 at 03:17:10PM +0300, Avi Kivity wrote: >> On 08/01/2010 01:53 PM, Gleb Natapov wrote: >>>> That requires everyone to update, or suffer major breakage. >>>> >>> They will suffer major breakage when they update to a kvm that calls to >>> kvm-tpr-opt.c from emulator anyway. >> Why? >> > Because tpr code will be called with wrong rip. Emulator always updated rip at the end > of an instruction emulation in writeback stage. > We can change it before switching enabling e_i_g_s by default. >>> So what can we do about it? >>> >> Keep the existing behaviour. >> > Existing behaviour will cause breakage. > The existing user-visible behaviour. The user doesn't know whether the emulator is involved or not. -- error compiling committee.c: too many arguments to function