From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752331AbdJFPdG (ORCPT ); Fri, 6 Oct 2017 11:33:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49228 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323AbdJFPdE (ORCPT ); Fri, 6 Oct 2017 11:33:04 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 53E2125775 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eric.auger@redhat.com Subject: Re: [PATCH v2 01/10] KVM: arm/arm64: vgic-its: fix return value for restore 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> <1506518920-18571-2-git-send-email-eric.auger@redhat.com> <87030c8b-2464-8602-5672-e9ad29a9db90@arm.com> Cc: wu.wubin@huawei.com From: Auger Eric Message-ID: <128854cd-9c5d-a990-b09c-c84e7e44a15a@redhat.com> Date: Fri, 6 Oct 2017 17:33:00 +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: <87030c8b-2464-8602-5672-e9ad29a9db90@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 [10.5.110.39]); Fri, 06 Oct 2017 15:33:04 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andre, On 06/10/2017 16:37, Andre Przywara wrote: > 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. Yes that's sadly true. Yep this error handling is a mess I must confess. I will try to better document and unify as much as possible. Thanks a lot for your review. Eric > > 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; >> } >>