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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 20C47C3A59E for ; Mon, 2 Sep 2019 13:00:14 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E61A8217F4 for ; Mon, 2 Sep 2019 13:00:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E61A8217F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id AB274E2C; Mon, 2 Sep 2019 13:00:13 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id AFEEAE27 for ; Mon, 2 Sep 2019 13:00:11 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 50BBA887 for ; Mon, 2 Sep 2019 13:00:11 +0000 (UTC) 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 B4399337; Mon, 2 Sep 2019 06:00:10 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BE5DD3F246; Mon, 2 Sep 2019 06:00:08 -0700 (PDT) Subject: Re: [PATCH 3/7] iommu/arm-smmu: Add tlb_sync implementation hook To: Krishna Reddy References: <1567118827-26358-1-git-send-email-vdumpa@nvidia.com> <1567118827-26358-4-git-send-email-vdumpa@nvidia.com> <554f8de1-1638-4eb9-59ae-8e1f0d786c44@arm.com> From: Robin Murphy Message-ID: <3d734164-51c9-3465-cddd-276093389797@arm.com> Date: Mon, 2 Sep 2019 14:00:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-GB Cc: Timo Alho , Thierry Reding , Mikko Perttunen , "linux-kernel@vger.kernel.org" , "will.deacon@arm.com" , "iommu@lists.linux-foundation.org" , Pritesh Raithatha , "Thomas Zeng \(SW-TEGRA\)" , Sachin Nikam , "linux-tegra@vger.kernel.org" , Yu-Huan Hsu , Juha Tukkinen , Alexander Van Brunt , "linux-arm-kernel@lists.infradead.org" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On 30/08/2019 23:49, Krishna Reddy wrote: >>> + if (smmu->impl->tlb_sync) { >>> + smmu->impl->tlb_sync(smmu, page, sync, status); > >> What I'd hoped is that rather than needing a hook for this, you could just override smmu_domain->tlb_ops from .init_context to wire up the alternate .sync method directly. That would save this extra level of indirection. > > Hi Robin, overriding tlb_ops->tlb_sync function is not enough here. > There are direct references to arm_smmu_tlb_sync_context(), arm_smmu_tlb_sync_global() functions. > In arm-smmu.c. we can replace these direct references with tlb_ops->tlb_sync() function except in one function arm_smmu_device_reset(). > When arm_smmu_device_reset() gets called, domains are not initialized and tlb_ops is not available. > Should we add a new hook for arm_smmu_tlb_sync_global() or make this as a responsibility of impl->reset() hook as it gets > called at the same place? Ah, right, I'd forgotten about the TLB maintenance on reset. Looking again, though, I think you might need to implement impl->reset anyway for the sake of clearing GFSR correctly - since the value read from the base instance technically may not match whatever bits might happen to be set in the other instances - so I don't see any issue with just calling nsmmu_tlb_sync() from there as well. Robin. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu