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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 9D6ADC56201 for ; Thu, 12 Nov 2020 09:35:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F5ED22203 for ; Thu, 12 Nov 2020 09:35:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="cnKe4HJz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726731AbgKLJfz (ORCPT ); Thu, 12 Nov 2020 04:35:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:37826 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbgKLJfy (ORCPT ); Thu, 12 Nov 2020 04:35:54 -0500 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C586621D40; Thu, 12 Nov 2020 09:35:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605173754; bh=jZvtOR3PtNvquvOxsY83AMLM9eQ6NrPnFVAxESmIl28=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cnKe4HJzQy1Z4Fa3OHn1PJ7Uh7RHRVdjgfXmxYJYHH7lF7Zi06HIbOiwghgMPlOHY SyVnBkxOeiSY1fd2ZB7tBZAKbJWxOpB8nqD6afena+H2UTTmaZf6YJipCEisreDZso YcX9r7FjcfOuOxk8SMu0snM+yi0uuhmEazJHAGdw= Date: Thu, 12 Nov 2020 09:35:48 +0000 From: Will Deacon To: Sai Prakash Ranjan Cc: Robin Murphy , Joerg Roedel , Jordan Crouse , Rob Clark , iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Akhil P Oommen , freedreno@lists.freedesktop.org, "Kristian H . Kristensen" , dri-devel@lists.freedesktop.org Subject: Re: [PATCHv7 2/7] iommu/arm-smmu: Add domain attribute for system cache Message-ID: <20201112093547.GA19049@willie-the-truck> References: <20201110121835.GC16239@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 11, 2020 at 12:10:50PM +0530, Sai Prakash Ranjan wrote: > On 2020-11-10 17:48, Will Deacon wrote: > > On Fri, Oct 30, 2020 at 02:53:09PM +0530, Sai Prakash Ranjan wrote: > > > Add iommu domain attribute for using system cache aka last level > > > cache by client drivers like GPU to set right attributes for caching > > > the hardware pagetables into the system cache. > > > > > > Signed-off-by: Sai Prakash Ranjan > > > --- > > > drivers/iommu/arm/arm-smmu/arm-smmu.c | 17 +++++++++++++++++ > > > drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 + > > > include/linux/iommu.h | 1 + > > > 3 files changed, 19 insertions(+) > > > > > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c > > > b/drivers/iommu/arm/arm-smmu/arm-smmu.c > > > index b1cf8f0abc29..070d13f80c7e 100644 > > > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > > > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > > > @@ -789,6 +789,9 @@ static int arm_smmu_init_domain_context(struct > > > iommu_domain *domain, > > > if (smmu_domain->non_strict) > > > pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; > > > > > > + if (smmu_domain->sys_cache) > > > + pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_SYS_CACHE; > > > + > > > pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain); > > > if (!pgtbl_ops) { > > > ret = -ENOMEM; > > > @@ -1520,6 +1523,9 @@ static int arm_smmu_domain_get_attr(struct > > > iommu_domain *domain, > > > case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE: > > > *(int *)data = smmu_domain->non_strict; > > > return 0; > > > + case DOMAIN_ATTR_SYS_CACHE: > > > + *((int *)data) = smmu_domain->sys_cache; > > > + return 0; > > > default: > > > return -ENODEV; > > > } > > > @@ -1551,6 +1557,17 @@ static int arm_smmu_domain_set_attr(struct > > > iommu_domain *domain, > > > else > > > smmu_domain->stage = ARM_SMMU_DOMAIN_S1; > > > break; > > > + case DOMAIN_ATTR_SYS_CACHE: > > > + if (smmu_domain->smmu) { > > > + ret = -EPERM; > > > + goto out_unlock; > > > + } > > > + > > > + if (*((int *)data)) > > > + smmu_domain->sys_cache = true; > > > + else > > > + smmu_domain->sys_cache = false; > > > + break; > > > default: > > > ret = -ENODEV; > > > } > > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h > > > b/drivers/iommu/arm/arm-smmu/arm-smmu.h > > > index 885840f3bec8..dfc44d806671 100644 > > > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h > > > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h > > > @@ -373,6 +373,7 @@ struct arm_smmu_domain { > > > struct mutex init_mutex; /* Protects smmu pointer */ > > > spinlock_t cb_lock; /* Serialises ATS1* ops and TLB syncs */ > > > struct iommu_domain domain; > > > + bool sys_cache; > > > }; > > > > > > struct arm_smmu_master_cfg { > > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > > > index b95a6f8db6ff..4f4bb9c6f8f6 100644 > > > --- a/include/linux/iommu.h > > > +++ b/include/linux/iommu.h > > > @@ -118,6 +118,7 @@ enum iommu_attr { > > > DOMAIN_ATTR_FSL_PAMUV1, > > > DOMAIN_ATTR_NESTING, /* two stages of translation */ > > > DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, > > > + DOMAIN_ATTR_SYS_CACHE, > > > > I think you're trying to make this look generic, but it's really not. > > If we need to funnel io-pgtable quirks through domain attributes, then I > > think we should be open about that and add something like > > DOMAIN_ATTR_IO_PGTABLE_CFG which could take a struct of page-table > > configuration data for the domain (this could just be quirks initially, > > but maybe it's worth extending to take ias, oas and page size) > > > > Actually the initial versions used DOMAIN_ATTR_QCOM_SYS_CACHE > to make it QCOM specific and not generic, I don't see anyone else > using this attribute, would that work? No -- I'd prefer to have _one_ domain attribute for funneling all the IP_PGTABLE_CFG data. Otherwise, we'll just end up with things like DOMAIN_ATTR_QCOM_SYS_CACHE_EXT or DOMAIN_ATTR_QCOM_QUIRKS later on. Will