From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v2 04/15] xen: arm: add a quirk to handle platforms with unusual GIC layout Date: Fri, 22 Nov 2013 17:10:11 +0000 Message-ID: <528F8FF3.4060005@linaro.org> References: <1385137474-31245-4-git-send-email-ian.campbell@citrix.com> <528F8A64.4040807@linaro.org> <1385139825.25845.125.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1385139825.25845.125.camel@kazak.uk.xensource.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: Ian Campbell Cc: stefano.stabellini@eu.citrix.com, pranavkumar@linaro.org, tim@xen.org, Anup Patel , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 11/22/2013 05:03 PM, Ian Campbell wrote: > On Fri, 2013-11-22 at 16:46 +0000, Julien Grall wrote: >> >> On 11/22/2013 04:24 PM, Ian Campbell wrote: >>> Use this quirk on the xgene platform. >> >> With this quirk you only fix xen GIC. What about dom0/guest GIC ? I know >> that Linux is not using the secondary page, but we expose 2 pages >> contiguous page. With this quirk the first page is valid ... but the >> second page could belong to another device. > > Damn, good point. > >> Can we remove the second page when the quirk is enabled? > > I think what I will do is make gicv_setup map the two discontiguous 4K > regions contiguously into the guest space. This is consistent with the > DTB we expose to the guest. > > The reason for the discontinuity at the h/w level is (AFAICT) to support > OSes using 64K pages and/or granules. I think we can live without these > for the time being. I'm fine with this solution as long as we are sure there is no device memory just after the first page. -- Julien Grall