From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758056AbdJMLoP (ORCPT ); Fri, 13 Oct 2017 07:44:15 -0400 Received: from mail-wm0-f50.google.com ([74.125.82.50]:49487 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753258AbdJMLoH (ORCPT ); Fri, 13 Oct 2017 07:44:07 -0400 X-Google-Smtp-Source: AOwi7QB+nuva1Ok1tgU7JWu4+7VQ0ypbFQlCLc+38Z2zt7EfOby6y18poT9PimqO7X3+7+Cs2rdlpQ== Date: Fri, 13 Oct 2017 13:44:12 +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: <20171013114412.GG8927@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 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? Thanks, -Christoffer > > > > What am I missing here? > > > > Cheers, > > Andre. > > > >> Signed-off-by: Eric Auger > >> > >> --- > >> > >> need to CC stable > >> --- > >> virt/kvm/arm/vgic/vgic-its.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > >> index fbbc97b..76bed2d 100644 > >> --- a/virt/kvm/arm/vgic/vgic-its.c > >> +++ b/virt/kvm/arm/vgic/vgic-its.c > >> @@ -1329,7 +1329,7 @@ static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its, > >> > >> reg = update_64bit_reg(its->cwriter, addr & 7, len, val); > >> reg = ITS_CMD_OFFSET(reg); > >> - if (reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) { > >> + if (reg && reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) { > >> mutex_unlock(&its->cmd_lock); > >> return; > >> } > >> @@ -1370,7 +1370,7 @@ static int vgic_mmio_uaccess_write_its_creadr(struct kvm *kvm, > >> } > >> > >> cmd_offset = ITS_CMD_OFFSET(val); > >> - if (cmd_offset >= ITS_CMD_BUFFER_SIZE(its->cbaser)) { > >> + if (cmd_offset && cmd_offset >= ITS_CMD_BUFFER_SIZE(its->cbaser)) { > >> ret = -EINVAL; > >> goto out; > >> } > >>