From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM: VMX: Conditionally reload debug register 6 Date: Tue, 01 Sep 2009 15:54:59 +0300 Message-ID: <4A9D19A3.1000500@redhat.com> References: <1251805232-16885-1-git-send-email-avi@redhat.com> <4A9D08D2.1020407@siemens.com> <4A9D0B47.20805@redhat.com> <4A9D144B.1020807@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , "kvm@vger.kernel.org" To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:41990 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754253AbZIAMzC (ORCPT ); Tue, 1 Sep 2009 08:55:02 -0400 In-Reply-To: <4A9D144B.1020807@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/01/2009 03:32 PM, Jan Kiszka wrote: > I'm worried about vm-exits that may take precedence over the #db trap. > If we skip to save/restore dr6 for them, the value that the interception > handler sees later on will be bogus. Or is this architecturally impossible? > I think it's architectually impossible. Debug traps take effect after the instruction executed, so if we made it to that point, nothing else can cause the vmexit. -- error compiling committee.c: too many arguments to function