From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: Requesting for freeze exception for ARM/ITS patches Date: Tue, 14 Jul 2015 08:49:15 +0100 Message-ID: <1436860155.7019.137.camel@citrix.com> References: <20150713135504.GK4108@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: 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: Stefano Stabellini Cc: Wei Liu , Vijay Kilari , Prasun Kapoor , manish.jaggi@caviumnetworks.com, "xen-devel@lists.xen.org" , Julien Grall , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On Mon, 2015-07-13 at 18:24 +0100, Stefano Stabellini wrote: > On Mon, 13 Jul 2015, Wei Liu wrote: > > On Fri, Jul 10, 2015 at 04:16:07PM +0530, Vijay Kilari wrote: > > > Hi Wei, > > > > > > I would like to have freeze exception for ITS feature on ARM64. > > > Design got freeze few weeks back and I have sent v4 version of patch series > > > today. > > > > > > This patches will not impact any generic code of other platforms and have minor > > > changes generic arm related code. Also these patches are only for > > > ARM64 platform. > > > > > > These patches are pre-requisite for PCI support / Pass-through support > > > on ARM64 platforms. > > > > > > The risk is minor and as of today only used by Cavium ThunderX platform. > > > > > > > > > I'm not a ARM expert, but last time I checked most patches in v3 are not > > acked. > > > > I also got conflict statements from maintainers and core developer. I > > will wait a bit for them clarify the situation. > > > > But as Ian said, if you can't post v4 and get most if all of your > > patches acked / reviewed early this week, my answer to this request > > would be no. > > I pretty much agree with Ian: I went through the patches and the impact > of the series on non-ITS platforms will be null after Vijay addresses: > > - the lpi irq_desc and irq_pending allocation issues > - improve lpi_supported to check for ITS presence > > these two changes should be trivial and are certainly necessary for a > freeze exception in my view. > > > On this basis, if Vijay manages to resend a v5 version on time with > those two issues covered, making sure that the new code is not enabled > unless an its is present, then I think that a freeze exception would be > OK as the risk would be zero. I don't think we should be limiting ourselves to only fixing issues which reduce the risk on non-ITS platforms. So the two issues which you highlight above are necessary but not sufficient for a freeze exception in my view. For example I am firmly of the opinion that the VPLI injection code needs to be corrected as discussed during review. Likewise I said that care needs to be taken wrt when any of this code is enabled, which includes not exposing it to domU even on platforms which support ITS. I also view this as a requirement for a freeze exception. In other words only dom0 and only on an ITS enabled system should be exposed to any aspect of the ITS support. Ian.