From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH v4 07/17] x86/hvm: add length to mmio check op Date: Thu, 25 Jun 2015 13:21:27 +0100 Message-ID: <558BF247.9000208@citrix.com> References: <1435145089-21999-1-git-send-email-paul.durrant@citrix.com> <1435145089-21999-8-git-send-email-paul.durrant@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" 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 1Z869t-0002HH-4w for xen-devel@lists.xenproject.org; Thu, 25 Jun 2015 12:21:33 +0000 In-Reply-To: <1435145089-21999-8-git-send-email-paul.durrant@citrix.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: Paul Durrant , xen-devel@lists.xenproject.org Cc: Keir Fraser , Jan Beulich List-Id: xen-devel@lists.xenproject.org On 24/06/15 12:24, Paul Durrant wrote: > When memory mapped I/O is range checked by internal handlers, the length > of the access should be taken into account. > > Signed-off-by: Paul Durrant > Cc: Keir Fraser > Cc: Jan Beulich > Cc: Andrew Cooper > For what purpose? The length of the access doesn't affect which handler should accept the IO. This length check now causes an MMIO handler to not claim an access which straddles the upper boundary. It is probably fine to terminate such an access early, but it isn't fine to pass such a straddled access to the default ioreq server. ~Andrew