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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 673FAC433EF for ; Fri, 8 Oct 2021 12:14:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4577360F92 for ; Fri, 8 Oct 2021 12:14:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240457AbhJHMQX (ORCPT ); Fri, 8 Oct 2021 08:16:23 -0400 Received: from foss.arm.com ([217.140.110.172]:47704 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240715AbhJHMQX (ORCPT ); Fri, 8 Oct 2021 08:16:23 -0400 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 C30DFED1; Fri, 8 Oct 2021 05:14:27 -0700 (PDT) Received: from [10.57.22.120] (unknown [10.57.22.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6E72F3F766; Fri, 8 Oct 2021 05:14:25 -0700 (PDT) Subject: Re: [PATCH v7 1/9] iommu: Introduce a union to struct iommu_resv_region To: Shameer Kolothum , linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org Cc: jon@solid-run.com, linuxarm@huawei.com, steven.price@arm.com, guohanjun@huawei.com, yangyicong@huawei.com, Sami.Mujawar@arm.com, will@kernel.org, wanghuiqiang@huawei.com References: <20210805080724.480-1-shameerali.kolothum.thodi@huawei.com> <20210805080724.480-2-shameerali.kolothum.thodi@huawei.com> From: Robin Murphy Message-ID: Date: Fri, 8 Oct 2021 13:14:19 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20210805080724.480-2-shameerali.kolothum.thodi@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 2021-08-05 09:07, Shameer Kolothum wrote: > A union is introduced to struct iommu_resv_region to hold > any firmware specific data. This is in preparation to add > support for IORT RMR reserve regions and the union now holds > the RMR specific information. > > Signed-off-by: Shameer Kolothum > --- > include/linux/iommu.h | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 32d448050bf7..bd0e4641c569 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -114,6 +114,13 @@ enum iommu_resv_type { > IOMMU_RESV_SW_MSI, > }; > > +struct iommu_iort_rmr_data { > +#define IOMMU_RMR_REMAP_PERMITTED (1 << 0) > + u32 flags; > + u32 sid; /* Stream Id associated with RMR entry */ > + void *smmu; /* Associated IORT SMMU node pointer */ > +}; Do we really need to duplicate all this data? AFAICS we could just save the acpi_iort_rmr pointer in the iommu_resv_region (with a forward declaration here if necessary) and defer parsing its actual mappings until the point where we can directly consume the results. Robin. > + > /** > * struct iommu_resv_region - descriptor for a reserved memory region > * @list: Linked list pointers > @@ -121,6 +128,7 @@ enum iommu_resv_type { > * @length: Length of the region in bytes > * @prot: IOMMU Protection flags (READ/WRITE/...) > * @type: Type of the reserved region > + * @rmr: ACPI IORT RMR specific data > */ > struct iommu_resv_region { > struct list_head list; > @@ -128,6 +136,9 @@ struct iommu_resv_region { > size_t length; > int prot; > enum iommu_resv_type type; > + union { > + struct iommu_iort_rmr_data rmr; > + } fw_data; > }; > > /** >