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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 B06BFC4346E for ; Thu, 24 Sep 2020 08:28:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 262DD221EB for ; Thu, 24 Sep 2020 08:28:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 262DD221EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AD96D900010; Thu, 24 Sep 2020 04:28:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A62EB90000C; Thu, 24 Sep 2020 04:28:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 978A2900010; Thu, 24 Sep 2020 04:28:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0137.hostedemail.com [216.40.44.137]) by kanga.kvack.org (Postfix) with ESMTP id 74E2E90000C for ; Thu, 24 Sep 2020 04:28:39 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 325413636 for ; Thu, 24 Sep 2020 08:28:39 +0000 (UTC) X-FDA: 77297278758.02.moon54_3e185e12715d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id F1AAC101528F4 for ; Thu, 24 Sep 2020 08:28:38 +0000 (UTC) X-HE-Tag: moon54_3e185e12715d X-Filterd-Recvd-Size: 2320 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by imf44.hostedemail.com (Postfix) with ESMTP for ; Thu, 24 Sep 2020 08:28:38 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id 9CBAC295; Thu, 24 Sep 2020 10:28:36 +0200 (CEST) Date: Thu, 24 Sep 2020 10:28:30 +0200 From: Joerg Roedel To: Marek Szyprowski Cc: Shaik Ameer Basha , Robin Murphy , Ajay kumar , Linux IOMMU , linux-mm@kvack.org, Rob Clark , Thierry Reding , jean-philippe@linaro.org, will@kernel.org, hch@lst.de, baolu.lu@linux.intel.com, Shaik Ameer Basha Subject: Re: IOVA allocation dependency between firmware buffer and remaining buffers Message-ID: <20200924082830.GB27174@8bytes.org> References: <59cda41f-170c-a1ad-a345-bc38b9ed4d73@arm.com> <11584d09-5995-6133-3bd3-8f7a0afd0e01@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11584d09-5995-6133-3bd3-8f7a0afd0e01@samsung.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Sep 23, 2020 at 08:48:26AM +0200, Marek Szyprowski wrote: > It allows to remap given buffer at the specific IOVA address, although > it doesn't guarantee that those specific addresses won't be later used > by the IOVA allocator. Probably it would make sense to add an API for > generic IOMMU-DMA framework to mark the given IOVA range as > reserved/unused to protect them. There is an API for that, the IOMMU driver can return IOVA reserved regions per device and the IOMMU core code will take care of mapping these regions and reserving them in the IOVA allocator, so that DMA-IOMMU code will not use it for allocations. Have a look at the iommu_ops->get_resv_regions() and iommu_ops->put_resv_regions(). Regards, Joerg