From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH 4/6] x86/NPT: don't walk entire page tables when changing types on a range Date: Fri, 18 Apr 2014 18:01:40 -0400 Message-ID: <5351A0C4.8070807@oracle.com> References: <535011EB020000780000A19A@nat28.tlf.novell.com> <53501375020000780000A1C4@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WbGnh-0002MP-AT for xen-devel@lists.xenproject.org; Fri, 18 Apr 2014 21:58:25 +0000 In-Reply-To: <53501375020000780000A1C4@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: Kevin Tian , Keir Fraser , suravee.suthikulpanit@amd.com, Tim Deegan , Eddie Dong , Jun Nakajima , xen-devel List-Id: xen-devel@lists.xenproject.org On 04/17/2014 11:46 AM, Jan Beulich wrote: > This builds on the fact that in order for no NPF VM exit to occur, > _PAGE_USER must always be set. I.e. by clearing the flag we can force a > VM exit allowing us to do similar lazy type changes as on EPT. > > That way, the generic entry-wise code can go away, and we could remove > the range restriction in enforced on HVMOP_track_dirty_vram for XSA-27. > > Signed-off-by: Jan Beulich I am not particularly familiar with p2m code which is why my only comment so far is to add comments in the code ;-) --- there is a bunch of new non-trivial (to my eye) routines and so having a little bit of text would greatly help with understanding the logic. -boris