From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751932AbdJFP3I (ORCPT ); Fri, 6 Oct 2017 11:29:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59769 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750915AbdJFP3H (ORCPT ); Fri, 6 Oct 2017 11:29:07 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D018B2CE949 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eric.auger@redhat.com Subject: Re: [PATCH v2 02/10] KVM: arm/arm64: vgic-its: Always allow clearing GITS_CREADR/CWRITER To: Andre Przywara , 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 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> Cc: wu.wubin@huawei.com From: Auger Eric Message-ID: Date: Fri, 6 Oct 2017 17:29:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <4315e223-a843-50d9-506d-a3902ee8d18d@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 06 Oct 2017 15:29:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks! Eric > > 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; >> } >>