From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH v2] KVM: VMX: Conditionally reload debug register 6 Date: Thu, 03 Sep 2009 10:20:51 +0200 Message-ID: <4A9F7C63.70000@siemens.com> References: <1251810385-21050-1-git-send-email-avi@redhat.com> <20090902185453.GA4238@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , "kvm@vger.kernel.org" To: Marcelo Tosatti Return-path: Received: from thoth.sbs.de ([192.35.17.2]:22817 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752174AbZICIVG (ORCPT ); Thu, 3 Sep 2009 04:21:06 -0400 In-Reply-To: <20090902185453.GA4238@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > On Tue, Sep 01, 2009 at 04:06:25PM +0300, Avi Kivity wrote: >> Only reload debug register 6 if we're running with the guest's >> debug registers. Saves around 150 cycles from the guest lightweight >> exit path. >> >> dr6 contains a couple of bits that are updated on #DB, so intercept >> that unconditionally and update those bits then. > > Applied, thanks. > Will send a cleanup patch based on the discussion with Avi later. It just requires some testing. And I also have a kgdb-safe(r) version of the switch optimization here. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux