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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4322FC433EF for ; Mon, 29 Nov 2021 13:14:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WYfnFbKiKtUHf3TEYSJbjEqj9pJaG/S1QCzHeGMbqW8=; b=zIxTPzwiSPod7b FuL751Gd+wHbFmbWnUYaPoY+j4n+qDVsxD8e6Xu/joDggm8dBxFkl6pjvXVx0leXrCSzL6pTboo8W zuwzmH94FFk1Wu9SnEnzmNTFbQNS2JGi7D28XVedqTwBqN0J/80j0+7m5B7knGBaEuU7wWLo8lM/+ aQgObpAZevQ/Z/MOjwh9L4ADYeNL8ZkWPfSjk8PBooRqwiIFGK0EGOklYI/DCCa1X7yzPZWGf/zKW nD3kQUz0WEqJn8ms3evHqTehAlAf1cp08ZKUexY315A9RtZs2jeR2WyEmiiXAysvDPWe2tQwSrsmr f+pivD7y+r+wjrdZ7Pvw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mrgTG-000oWG-2q; Mon, 29 Nov 2021 13:13:26 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mrgTC-000oV6-8e for linux-arm-kernel@lists.infradead.org; Mon, 29 Nov 2021 13:13:23 +0000 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 616131515; Mon, 29 Nov 2021 05:13:19 -0800 (PST) Received: from [10.57.34.182] (unknown [10.57.34.182]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 317153F766; Mon, 29 Nov 2021 05:13:15 -0800 (PST) Message-ID: <76a1b5c1-01c8-bb30-6105-b4073dc23065@arm.com> Date: Mon, 29 Nov 2021 13:13:11 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [patch 33/37] iommu/arm-smmu-v3: Use msi_get_virq() Content-Language: en-GB To: Will Deacon , Thomas Gleixner Cc: Nishanth Menon , Mark Rutland , Stuart Yoder , linux-pci@vger.kernel.org, Ashok Raj , Marc Zygnier , x86@kernel.org, Sinan Kaya , iommu@lists.linux-foundation.org, Bjorn Helgaas , Megha Dey , Jason Gunthorpe , Kevin Tian , Alex Williamson , Santosh Shilimkar , linux-arm-kernel@lists.infradead.org, Tero Kristo , Greg Kroah-Hartman , LKML , Vinod Koul , dmaengine@vger.kernel.org References: <20211126224100.303046749@linutronix.de> <20211126230525.885757679@linutronix.de> <20211129105506.GA22761@willie-the-truck> From: Robin Murphy In-Reply-To: <20211129105506.GA22761@willie-the-truck> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211129_051322_447704_1C88C117 X-CRM114-Status: GOOD ( 18.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2021-11-29 10:55, Will Deacon wrote: > Hi Thomas, > > On Sat, Nov 27, 2021 at 02:20:59AM +0100, Thomas Gleixner wrote: >> Let the core code fiddle with the MSI descriptor retrieval. >> >> Signed-off-by: Thomas Gleixner >> --- >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 19 +++---------------- >> 1 file changed, 3 insertions(+), 16 deletions(-) >> >> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> @@ -3154,7 +3154,6 @@ static void arm_smmu_write_msi_msg(struc >> >> static void arm_smmu_setup_msis(struct arm_smmu_device *smmu) >> { >> - struct msi_desc *desc; >> int ret, nvec = ARM_SMMU_MAX_MSIS; >> struct device *dev = smmu->dev; >> >> @@ -3182,21 +3181,9 @@ static void arm_smmu_setup_msis(struct a >> return; >> } >> >> - for_each_msi_entry(desc, dev) { >> - switch (desc->msi_index) { >> - case EVTQ_MSI_INDEX: >> - smmu->evtq.q.irq = desc->irq; >> - break; >> - case GERROR_MSI_INDEX: >> - smmu->gerr_irq = desc->irq; >> - break; >> - case PRIQ_MSI_INDEX: >> - smmu->priq.q.irq = desc->irq; >> - break; >> - default: /* Unknown */ >> - continue; >> - } >> - } >> + smmu->evtq.q.irq = msi_get_virq(dev, EVTQ_MSI_INDEX); >> + smmu->gerr_irq = msi_get_virq(dev, GERROR_MSI_INDEX); >> + smmu->priq.q.irq = msi_get_virq(dev, PRIQ_MSI_INDEX); > > Prviously, if retrieval of the MSI failed then we'd fall back to wired > interrupts. Now, I think we'll clobber the interrupt with 0 instead. Can > we make the assignments to smmu->*irq here conditional on the MSI being > valid, please? I was just looking at that too, but reached the conclusion that it's probably OK, since consumption of this value later is gated on ARM_SMMU_FEAT_PRI, so the fact that it changes from 0 to an error value in the absence of PRI should make no practical difference. If we don't have MSIs at all, we'd presumably still fail earlier either at the dev->msi_domain check or upon trying to allocate the vectors, so we'll still fall back to any previously-set wired values before getting here. The only remaining case is if we've *successfully* allocated the expected number of vectors yet are then somehow unable to retrieve one or more of them - presumably the system has to be massively borked for that to happen, at which point do we really want to bother trying to reason about anything? Robin. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel