From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH 2/2] xen: arm: Set all bits in mfn_to_xen_entry() Date: Mon, 17 Aug 2015 12:03:30 -0700 Message-ID: <55D23002.3040005@citrix.com> References: <4EE5B48738DDED408878C97C8E050A8B1D7EC7F5@SJEXCHMB05.corp.ad.broadcom.com> <55D22CB0.1020903@citrix.com> <4EE5B48738DDED408878C97C8E050A8B1D7F02CF@SJEXCHMB05.corp.ad.broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4EE5B48738DDED408878C97C8E050A8B1D7F02CF@SJEXCHMB05.corp.ad.broadcom.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: "Chris (Christopher) Brand" , "xen-devel@lists.xen.org" Cc: "stefano.stabellini@citrix.com" , "Ian Campbell (ian.campbell@citrix.com)" List-Id: xen-devel@lists.xenproject.org On 17/08/2015 11:58, Chris (Christopher) Brand wrote: > Hi Julien, > > Thanks for the review. > >>> + .pxn = 0, >> >> I would add a comment to explain that this bit is reserved for PL2 stage >> 1 page table. > > Will do. > >>> + .avail = 0, >> >> I don't think this one is necessary. avail is not used by the hardware neither >> Xen. > > "grep -rF pt.avail xen" gives 7 matches in xen/arch/arm/mm.c, so it is used by > Xen (I'll fully admit that I didn't dig in to the "how and why" of its use). Hmmm right. Sorry I haven't check the Xen code for that. It's used for domheap mapping to know how many times it has been referenced. > >> what about *t fields (pxnt, xnt, apt,...)? > > I figured that as we're setting table to 0, these are ignored, and any code setting > table to 1 should then set them. I can obviously easily set them here (I guess all > to zero would make sense) if you think it's worthwhile ... It was just an open question. :) I'm not sure what we should do with them. Regards, -- Julien Grall