From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH for-4.6] xen/arm: vgic-v2: Map the GIC virtual CPU interface with the correct size Date: Mon, 21 Sep 2015 12:54:06 +0100 Message-ID: <1442836446.10338.59.camel@citrix.com> References: <1442512803-798-1-git-send-email-julien.grall@citrix.com> <1442566410.18856.252.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" 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 1ZdzgC-0003F2-IT for xen-devel@lists.xenproject.org; Mon, 21 Sep 2015 11:54:44 +0000 In-Reply-To: <1442566410.18856.252.camel@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: Julien Grall , xen-devel@lists.xenproject.org Cc: stefano.stabellini@citrix.com, Wei.Liu2@citrix.com List-Id: xen-devel@lists.xenproject.org On Fri, 2015-09-18 at 09:53 +0100, Ian Campbell wrote: > On Thu, 2015-09-17 at 19:00 +0100, Julien Grall wrote: > > On GICv2, the GIC virtual CPU interface is at minimum 8KB. Due some to > > some necessary quirk for GIC using 64KB stride, we are mapping the > > region in 2 time. > > The first mapping is 4KB and the second one is 8KB, i.e 12KB in total. > > Although the minimum supported size (and widely used) is 8KB. This > > means > > that we are mapping 4KB more to any guest using GICv2. > > > > While this looks scary at first glance, the GIC virtual CPU interface > > is > > most frequently at the end the GIC I/O region. So we will most likely > > map an an unused I/O region or a mirrored version of GICV for platform > > using 64KB stride. > > > > Nonetheless, fix the second mapping to only map 4KB. > > > > Signed-off-by: Julien Grall > > Acked-by: Ian Campbell > > > --- > > > > This is a candidate for Xen 4.6 and backport to Xen 4.5. > > I concur and with Wei not being around I shall plan to apply later today > unless there are objections. I got distracted. Now applied to staging and staging-4.6 now and noted for later application to 4.5