From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH] VMX: Eliminate cr3 store/load vmexit when UG enabled Date: Mon, 28 Oct 2013 13:52:08 +0000 Message-ID: <526E6C08.9020704@citrix.com> References: <1382513945-9479-1-git-send-email-yang.z.zhang@intel.com> <5267DFE7.5000802@citrix.com> <526E732E02000078000FD475@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <526E732E02000078000FD475@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: Yang Z Zhang , "xen-devel@lists.xensource.com" , Eddie Dong , Jun Nakajima List-Id: xen-devel@lists.xenproject.org On 28/10/13 13:22, Jan Beulich wrote: >>>> On 24.10.13 at 06:41, "Zhang, Yang Z" wrote: >> Andrew Cooper wrote on 2013-10-23: >>> On 23/10/13 08:39, Yang Zhang wrote: >>>> From: Yang Zhang >>>> >>>> With the feature of unrestricted guest, there should no vmexit be >>>> triggered when guest accesses the cr3 in non-paging mode. >>>> >>>> Signed-off-by: Yang Zhang >>> You English here confused me for a bit. I presume you mean "Xen >>> should not cause vmexits for cr3 accesses in unrestricted guests", >>> whereas the current meaning implies that hardware wont generate a >>> vmexit for cr3 accesses for unrestricted guests (which is not correct >> according to the SDM). >> Apology for my poor English. Yes, your understanding is right. > So assuming we'll get an ack from one of the VMX maintainers, > should this then be committed with the suggested change to the > description? Also, Andrew, any more concerns regarding this > change (IOW did Yang address your earlier questions)? > > Jan > I think so, but I really don't think I know the implications of the changes well enough to be happy giving it a Reviewed-by tag. Given the clarification regarding the commit message, I shall defer to the maintainers for the correctness of the change. ~Andrew