From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4FECC433E0 for ; Wed, 6 Jan 2021 16:33:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A1962312F for ; Wed, 6 Jan 2021 16:33:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727485AbhAFQdK (ORCPT ); Wed, 6 Jan 2021 11:33:10 -0500 Received: from foss.arm.com ([217.140.110.172]:43832 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727406AbhAFQdK (ORCPT ); Wed, 6 Jan 2021 11:33:10 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 66309106F; Wed, 6 Jan 2021 08:32:24 -0800 (PST) Received: from [192.168.0.110] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E07033F719; Wed, 6 Jan 2021 08:32:22 -0800 (PST) Subject: Re: [PATCH 1/9] KVM: arm64: vgic-v3: Fix some error codes when setting RDIST base To: Eric Auger , eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, maz@kernel.org, drjones@redhat.com Cc: james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, shuah@kernel.org, pbonzini@redhat.com References: <20201212185010.26579-1-eric.auger@redhat.com> <20201212185010.26579-2-eric.auger@redhat.com> From: Alexandru Elisei Message-ID: Date: Wed, 6 Jan 2021 16:32:23 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20201212185010.26579-2-eric.auger@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric, On 12/12/20 6:50 PM, Eric Auger wrote: > KVM_DEV_ARM_VGIC_GRP_ADDR group doc says we should return > -EEXIST in case the base address of the redist is already set. > We currently return -EINVAL. > > However we need to return -EINVAL in case a legacy REDIST address > is attempted to be set while REDIST_REGIONS were set. This case > is discriminated by looking at the count field. > > Signed-off-by: Eric Auger > --- > arch/arm64/kvm/vgic/vgic-mmio-v3.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c > index 15a6c98ee92f..8e8a862def76 100644 > --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c > +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c > @@ -792,8 +792,13 @@ static int vgic_v3_insert_redist_region(struct kvm *kvm, uint32_t index, > int ret; > > /* single rdist region already set ?*/ > - if (!count && !list_empty(rd_regions)) > - return -EINVAL; > + if (!count && !list_empty(rd_regions)) { > + rdreg = list_last_entry(rd_regions, > + struct vgic_redist_region, list); > + if (rdreg->count) > + return -EINVAL; /* Mixing REDIST and REDIST_REGION API */ > + return -EEXIST; > + } A few instructions below:     if (list_empty(rd_regions)) {         [..]     } else {         rdreg = list_last_entry(rd_regions,                     struct vgic_redist_region, list);         [..]         /* Cannot add an explicitly sized regions after legacy region */         if (!rdreg->count)             return -EINVAL;     } Isn't this testing for the same thing, but using the opposite condition? Or am I misunderstanding the code (quite likely)? Looks to me like KVM_DEV_ARM_VGIC_GRP_ADDR(KVM_VGIC_V3_ADDR_TYPE_REDIST{,_REGION}) used to return -EEXIST (from vgic_check_ioaddr()) before commit ccc27bf5be7b7 ("KVM: arm/arm64: Helper to register a new redistributor region") which added the vgic_v3_insert_redist_region() function, so bringing back the -EEXIST return code looks the right thing to me. Thanks, Alex > > /* cross the end of memory ? */ > if (base + size < base)