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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 0B480C64E7B for ; Wed, 2 Dec 2020 14:40:20 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 783BF21D7F for ; Wed, 2 Dec 2020 14:40:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 783BF21D7F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.42779.76985 (Exim 4.92) (envelope-from ) id 1kkTIa-00030g-8b; Wed, 02 Dec 2020 14:40:04 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 42779.76985; Wed, 02 Dec 2020 14:40:04 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kkTIa-0002zx-4s; Wed, 02 Dec 2020 14:40:04 +0000 Received: by outflank-mailman (input) for mailman id 42779; Wed, 02 Dec 2020 14:40:02 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kkTIX-0002eh-TN for xen-devel@lists.xenproject.org; Wed, 02 Dec 2020 14:40:02 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kkTIX-0003A7-I1; Wed, 02 Dec 2020 14:40:01 +0000 Received: from [54.239.6.187] (helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1kkTIX-00031E-Af; Wed, 02 Dec 2020 14:40:01 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=+hRPY9g6YRAHj9s3GL8eUWDrrun+ZidHmmbIACfNpS8=; b=u1zcfHICyNIyvWtZUuBx2wgRc/ s0O9aNWb1zYdImVmytsJtRJz3TDWxJvumQi21j7fauxpUzOWx4X/KconPnZL0F2AD8OydVNMz+b+4 P1ZqXYnDqxzJXp5IOSQ2aWOozkGviOLNNLzG6dFP3oIdjWGUMiCkgbeVrLA2k0G2zs60=; Subject: Re: [PATCH v2 7/8] xen/arm: Remove Linux specific code that is not usable in XEN To: Rahul Singh , Stefano Stabellini Cc: "xen-devel@lists.xenproject.org" , Bertrand Marquis , Volodymyr Babchuk References: <1d9da8ed4845aeb9e86a5ce6750b811bd7e2020e.1606406359.git.rahul.singh@arm.com> <804B8C95-FF10-4FE5-AC82-9959EC9B8041@arm.com> From: Julien Grall Message-ID: Date: Wed, 2 Dec 2020 14:39:59 +0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <804B8C95-FF10-4FE5-AC82-9959EC9B8041@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Hi Rahul, On 02/12/2020 14:34, Rahul Singh wrote: >>> dev_info(smmu->dev, "ias %lu-bit, oas %lu-bit (features 0x%08x)\n", >>> @@ -2595,9 +2208,6 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev, >>> >>> parse_driver_options(smmu); >>> >>> - if (of_dma_is_coherent(dev->of_node)) >>> - smmu->features |= ARM_SMMU_FEAT_COHERENCY; >>> - >> >> Why this change? The ARM_SMMU_FEAT_COHERENCY flag is still used in >> arm_smmu_device_hw_probe. > > I remove this as this is linux specific. I will remove ARM_SMMU_FEAT_COHERENCY flag used in arm_smmu_device_hw_probe From my understanding, ARM_SMMU_FEAT_COHERENCY indicate whether the SMMU page table walker will snoop the cache. If the flag is not set, then Xen will have to clean to PoC every entry updated in the p2m. Therefore, I think we need to keep this code. In the case we don't need to keep the code, then I think the reason should be explained in the commit message. Cheers, -- Julien Grall