From mboxrd@z Thu Jan 1 00:00:00 1970 From: Izik Eidus Subject: Re: [PATCH 2/3] add SPTE_HOST_WRITEABLE flag to the shadow ptes Date: Mon, 14 Sep 2009 19:51:16 +0300 Message-ID: <4AAE7484.8040806@redhat.com> References: <1252600738-9456-1-git-send-email-ieidus@redhat.com> <1252600738-9456-2-git-send-email-ieidus@redhat.com> <1252600738-9456-3-git-send-email-ieidus@redhat.com> <20090914083417.GA3250@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: avi@redhat.com, kvm@vger.kernel.org, aarcange@redhat.com To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:64455 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751429AbZINQmi (ORCPT ); Mon, 14 Sep 2009 12:42:38 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n8EGgg0R012278 for ; Mon, 14 Sep 2009 12:42:42 -0400 In-Reply-To: <20090914083417.GA3250@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > Why can't you use the writable bit in the spte? So that you can only > sync a writeable spte if it was writeable before, in sync_page? > I could, but there we will add overhead for read only gptes that become writable in the guest... If you prefer to fault on the syncing of the guest gpte readonly to gpte writeable I can change it... What you prefer? > Is there any other need for the extra bit? > No