From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerhard Wiesinger Subject: Re: [PATCH] Fixed KVM problems with old DOS programs. Compatibility can be forced by module parameter. Date: Thu, 5 Nov 2015 17:07:39 +0100 Message-ID: <563B7ECB.9030504@wiesinger.com> References: <563A5D7D.4080201@wiesinger.com> <563A7827.8030506@redhat.com> <563A79B8.3020900@wiesinger.com> <563A80F4.6090204@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: Paolo Bonzini , kvm@vger.kernel.org Return-path: Received: from vps01.wiesinger.com ([46.36.37.179]:38650 "EHLO vps01.wiesinger.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033088AbbKEQHr (ORCPT ); Thu, 5 Nov 2015 11:07:47 -0500 In-Reply-To: <563A80F4.6090204@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 04.11.2015 23:04, Paolo Bonzini wrote: > > On 04/11/2015 22:33, Gerhard Wiesinger wrote: >>> What is the problem you are seeing? KVM can emulate task switches; the >>> intercept is set here because of a processor erratum that can mess them >>> up even though, in theory, AMD supports task switching from guest mode. >> See old thread: >> https://lists.nongnu.org/archive/html/qemu-devel/2012-04/msg01506.html > Can you obtain the traces you were asked for at the time? ./trace-cmd record -b 20000 -e kvm ./trace-cmd report | grep -i task_switch qemu-system-x86-6024 [001] 792774.719297: kvm_exit: reason task_switch rip 0x4883 info 158 4000000000 But I can't interpret it. But I know my patch works well. Since it is just a module parameter it is fully backward compatible by default and because of the one liner no side effects are possible. So a intergration would be good. Ciao, Gerhard