From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753014AbdJMRym (ORCPT ); Fri, 13 Oct 2017 13:54:42 -0400 Received: from mail-wm0-f42.google.com ([74.125.82.42]:52940 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752901AbdJMRyk (ORCPT ); Fri, 13 Oct 2017 13:54:40 -0400 X-Google-Smtp-Source: AOwi7QBOgIcA/Rn2L4atgX/8V6i77IC1EQAaIEClCBdGJobkcOtpAFf/bPLbqqqVPSMmaQHMwzPlHQ== Date: Fri, 13 Oct 2017 19:54:46 +0200 From: Christoffer Dall To: Auger Eric Cc: Andre Przywara , eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, marc.zyngier@arm.com, peter.maydell@linaro.org, wanghaibin.wang@huawei.com, wu.wubin@huawei.com Subject: Re: [PATCH v2 02/10] KVM: arm/arm64: vgic-its: Always allow clearing GITS_CREADR/CWRITER Message-ID: <20171013175446.GC17578@cbox> References: <1506518920-18571-1-git-send-email-eric.auger@redhat.com> <1506518920-18571-3-git-send-email-eric.auger@redhat.com> <4315e223-a843-50d9-506d-a3902ee8d18d@arm.com> <20171013114412.GG8927@cbox> <065e1e4c-e16d-5df6-ceff-3415a2d91e8d@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <065e1e4c-e16d-5df6-ceff-3415a2d91e8d@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 13, 2017 at 01:54:34PM +0200, Auger Eric wrote: > Hi Christoffer, > On 13/10/2017 13:44, Christoffer Dall wrote: > > On Fri, Oct 06, 2017 at 05:29:02PM +0200, Auger Eric wrote: > >> Hi, > >> > >> On 06/10/2017 16:37, Andre Przywara wrote: > >>> Hi, > >>> > >>> On 27/09/17 14:28, Eric Auger wrote: > >>>> If the GITS_CBASER Size field is 0, which can correspond to a > >>>> reset value, the userspace fails to set the GITS_CREADR/CWRITER > >>>> offsets to 0. This failure is not justified. > >>>> > >>>> Let's allow this setting which can also correspond to a reset value. > >>> > >>> But the GITS_CBASER size field has a +1 encoding, so can never be 0, if > >>> I understand the manual (and ITS_CMD_BUFFER_SIZE) correctly. > >> Oh OK, you're. I missed that. I would have sworn I've seen that failure > >> but I must have misinterpreted it. > >> > > > > What is CWRITER is written to a brand new ITS before the CBASER is > > written? > > > > I don't see us initializing the cbaser field anywhere? > in vgic_its_create() its is allocated with kzalloc so its->cbaser is > initialized at this moment. > Right, so it can be 0, and we still need your patch, contrary to Andre's comment. Am I missing something? Thanks, -Christoffer