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=-5.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 B2B42C47082 for ; Thu, 3 Jun 2021 08:01:00 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 13705613E3 for ; Thu, 3 Jun 2021 08:01:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 13705613E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id BFC80404F7; Thu, 3 Jun 2021 08:00:59 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6obL9Sq3lbeT; Thu, 3 Jun 2021 08:00:59 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp2.osuosl.org (Postfix) with ESMTP id C6A0740515; Thu, 3 Jun 2021 08:00:58 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id A490DC000E; Thu, 3 Jun 2021 08:00:58 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id E74AFC0001 for ; Thu, 3 Jun 2021 08:00:56 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id C77B8405BD for ; Thu, 3 Jun 2021 08:00:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id HKuRrRuoEHxy for ; Thu, 3 Jun 2021 08:00:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 8D47B40582 for ; Thu, 3 Jun 2021 08:00:55 +0000 (UTC) Received: from fraeml736-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4FwdLK2htKz6J9Tk; Thu, 3 Jun 2021 15:48:25 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml736-chm.china.huawei.com (10.206.15.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 3 Jun 2021 10:00:52 +0200 Received: from [10.47.80.115] (10.47.80.115) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 3 Jun 2021 09:00:51 +0100 Subject: Re: [PATCH v3 0/7] iommu: Allow IOVA rcache range be configured To: Lu Baolu , , , References: <1622557781-211697-1-git-send-email-john.garry@huawei.com> <834ad35a-7310-1738-7d17-7c061ca73e4c@linux.intel.com> <1cbf8cc2-8cee-0579-2514-56f664baa9cd@huawei.com> <5e6ff4d6-cd67-d4ab-814c-e10a258191b1@linux.intel.com> From: John Garry Message-ID: <74dd66d6-315c-3273-afaa-e6164b4ea33f@huawei.com> Date: Thu, 3 Jun 2021 09:00:45 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <5e6ff4d6-cd67-d4ab-814c-e10a258191b1@linux.intel.com> Content-Language: en-US X-Originating-IP: [10.47.80.115] X-ClientProxiedBy: lhreml751-chm.china.huawei.com (10.201.108.201) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Cc: iommu@lists.linux-foundation.org, linuxarm@huawei.com, linux-kernel@vger.kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 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" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 03/06/2021 01:39, Lu Baolu wrote: >> I did actually try increasing the range for a 'live' domain in the v1 >> series, but it turned out too messy. First problem is reallocating the >> memory to hold the rcaches. Second problem is that we need to deal >> with the issue that all IOVAs in the rcache need to be a pow-of-2, >> which is difficult to enforce for IOVAs which weren't being cached >> before, but now would be. >> >> So now I changed to work similar to how we change the default domain >> type, i.e. don't operate on a 'live' domain. > > If these hard restrictions on users are just to walk around the messy > code in kernel, I would rather solve those messy code to achieve a > better user experience. :-) Hi Baolu, It's not that the code is messy. I'm just saying that it's difficult to change the rcache range of a live domain. So we take an approach similar to changing the domain default type - it is more straightforward to configure the rcache range that way. Anyway, it would be great if you or anyone could look at the code so that some progress can be made here. Thanks, John _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu