From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752219AbdJFOhf (ORCPT ); Fri, 6 Oct 2017 10:37:35 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:35002 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751866AbdJFOha (ORCPT ); Fri, 6 Oct 2017 10:37:30 -0400 Subject: Re: [PATCH v2 02/10] KVM: arm/arm64: vgic-its: Always allow clearing GITS_CREADR/CWRITER To: Eric Auger , eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, marc.zyngier@arm.com, cdall@linaro.org, peter.maydell@linaro.org, wanghaibin.wang@huawei.com Cc: wu.wubin@huawei.com References: <1506518920-18571-1-git-send-email-eric.auger@redhat.com> <1506518920-18571-3-git-send-email-eric.auger@redhat.com> From: Andre Przywara Message-ID: <4315e223-a843-50d9-506d-a3902ee8d18d@arm.com> Date: Fri, 6 Oct 2017 15:37:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <1506518920-18571-3-git-send-email-eric.auger@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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; > } >