From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751966AbdJFOhO (ORCPT ); Fri, 6 Oct 2017 10:37:14 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:34984 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751487AbdJFOhM (ORCPT ); Fri, 6 Oct 2017 10:37:12 -0400 Subject: Re: [PATCH v2 01/10] KVM: arm/arm64: vgic-its: fix return value for restore 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> <1506518920-18571-2-git-send-email-eric.auger@redhat.com> From: Andre Przywara Message-ID: <87030c8b-2464-8602-5672-e9ad29a9db90@arm.com> Date: Fri, 6 Oct 2017 15:37:15 +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: <1506518920-18571-2-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: > From: wanghaibin > > This patch fix the migrate restore tables failure. > > The same scene, at the destination, the restore tables > interface traversal guest memory, and check the dte/ite > is valid or not. If all dtes/ites are invalid, we will do > try next one, and the last it will take the 1 return value, > but currently, it be treated as error. That's not correct. > > This patch try to fix this problem. > > Signed-off-by: wanghaibin Looks right to me. But I wonder if we actually should go over the file and unify the return value semantics or at least document them. It's a bit puzzling to have functions which return negative errors and 0 *or 1* on success, and then functions which go with the traditional C convention. That would help explaining the second hunk. Also this return value handling is a bit weird in cases, like in handle_l1_dte(): if (ret <= 0) return ret; return 1; which looks like a glorified "return ret;" in that case to me. But actually this is just nitpicking and the actual patch seems correct. Cheers, Andre. > --- > > need to CC stable > > v1 -> v2: > - if (ret > 0) ret = 0 > --- > 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 f51c1e1..fbbc97b 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -2018,7 +2018,7 @@ static int vgic_its_restore_dte(struct vgic_its *its, u32 id, > return PTR_ERR(dev); > > ret = vgic_its_restore_itt(its, dev); > - if (ret) { > + if (ret < 0) { > vgic_its_free_device(its->dev->kvm, dev); > return ret; > } > @@ -2141,7 +2141,7 @@ static int vgic_its_restore_device_tables(struct vgic_its *its) > } > > if (ret > 0) > - ret = -EINVAL; > + ret = 0; > > return ret; > } >