From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH] xen/arm: Implement domain_get_maximum_gpfn Date: Mon, 08 Sep 2014 13:43:07 -0700 Message-ID: <540E14DB.5000100@linaro.org> References: <1404226666-7949-1-git-send-email-julien.grall@linaro.org> <53BD29CD.4020204@linaro.org> <1405526542.1087.50.camel@kazak.uk.xensource.com> <5404E5D3.4010302@linaro.org> <1409733899.24834.2.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XR5mK-0005fm-1O for xen-devel@lists.xenproject.org; Mon, 08 Sep 2014 20:43:12 +0000 Received: by mail-qc0-f170.google.com with SMTP id r5so16301680qcx.15 for ; Mon, 08 Sep 2014 13:43:09 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Tamas K Lengyel , Ian Campbell Cc: "xen-devel@lists.xenproject.org" , Tim Deegan , Stefano Stabellini , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org Hello Tamas, On 03/09/14 02:00, Tamas K Lengyel wrote: > > > > On Wed, Sep 3, 2014 at 10:44 AM, Ian Campbell > wrote: > > On Mon, 2014-09-01 at 17:32 -0400, Julien Grall wrote: > > Hi Ian, > > > > On 16/07/14 12:02, Ian Campbell wrote: > > > I'd much prefer to just have the fix to xc_dom_gnttab_hvm_seed > for ARM > > > and continue to punt on this interface until it is actually > needed by > > > something unavoidable on the guest side (and simultaneously > hope that > > > day never comes...). > > > > This patch is a requirement to make Xen Memory access working on ARM. > > Could you reconsider the possibility to apply this patch on Xen? > > Needs more rationale as to why it is required for Xen Memory (do you > mean xenaccess?). I assume I'll find that in the relevant thread once I > get to it? > > > It's used in a non-critical sanity check for performance reasons, as > seen here: > https://github.com/tklengyel/xen/blob/arm_memaccess3/xen/common/mem_access.c#L75. > Without the sanity check we might attempt to set mem_access permissions > on gpfn's that don't exist for the guest. It wouldn't break anything to > do that but if we know beforehand that the gpfn is outside the scope of > what the guest has we can skip the entire thing. It might be better if you carry this patch on your series. Regards, -- Julien Grall