From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753475AbaCJMYY (ORCPT ); Mon, 10 Mar 2014 08:24:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21897 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752780AbaCJMYW (ORCPT ); Mon, 10 Mar 2014 08:24:22 -0400 Message-ID: <531DAEEA.8000909@redhat.com> Date: Mon, 10 Mar 2014 13:24:10 +0100 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= CC: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, alex.williamson@redhat.com, mtosatti@redhat.com, gleb@kernel.org, jan.kiszka@siemens.com Subject: Re: [PATCH 4/7] KVM: vmx: Allow the guest to run with dirty debug registers References: <1394192571-11056-1-git-send-email-pbonzini@redhat.com> <1394192571-11056-5-git-send-email-pbonzini@redhat.com> <20140309182639.GA10479@potion.redhat.com> <531CCB15.6070402@redhat.com> <20140310121704.GB16023@potion.brq.redhat.com> In-Reply-To: <20140310121704.GB16023@potion.brq.redhat.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 10/03/2014 13:17, Radim Krčmář ha scritto: >> > I considered this, but decided that it's unlikely for emulation to >> > be faster than hardware---especially on those AMD CPUs that lack >> > decode assists (and it's good for VMX and SVM code to look as >> > similar as possible). > I meant to move it before the block that exits if there is the > 'exception on access' bit set in cr7, so we wouldn't exit again right > away on the actual access, which is quite likely. > (Exiting without emulation was a great move.) > Ah yes, for the GD bit. I don't know, it's quite unlikely that anyone will use it... It's a feeble attempt at allowing virtualization of the debug registers without VMX. Paolo