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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 A3EF7C11F6A for ; Wed, 30 Jun 2021 06:54:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F4F461D0D for ; Wed, 30 Jun 2021 06:54:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232673AbhF3G5V (ORCPT ); Wed, 30 Jun 2021 02:57:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232453AbhF3G5S (ORCPT ); Wed, 30 Jun 2021 02:57:18 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96221C061766; Tue, 29 Jun 2021 23:54:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=f/Ss2iSM2QGOE0K5ddDAmgJLDWuc6gafnUUbn6I+ywE=; b=EjtYVsIFXW62/EkGI7hOZiVxWu WtQ1QOiJ+kE2LqSAajX/iny/lZxgDgpw4Lqlm87T+L3KdMUw9xtCm/qbkjnNm+n9HchMjHUuhlxdz w2OPufXyWbuv31Dot4DIGelHWZHewJ/p/raVKncRixUUmP7uchkRq1HvqmlhbTVJgHVFLODbv/YHA RNDQhV6qzSdLYF0g40BOD2Ta0/YGu2gzi83bR6eLmhaerMvfLzmNz8rtyEcmJ8Yhva1wvB3sNhoIm 1xB1suxXnDYbBmr21iG+4XFobuyQO+ec3qti7Yrj8KfMA7I5Z33WvXyyfut+u94vA1XrYQhuXZ2+W lhuwYjjA==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lyU6N-0050fY-DH; Wed, 30 Jun 2021 06:53:46 +0000 Date: Wed, 30 Jun 2021 07:53:39 +0100 From: Christoph Hellwig To: Jason Wang Cc: Alex Williamson , Jason Gunthorpe , Jean-Philippe Brucker , "Tian, Kevin" , "Jiang, Dave" , "Raj, Ashok" , "kvm@vger.kernel.org" , Jonathan Corbet , David Woodhouse , LKML , Kirti Wankhede , "iommu@lists.linux-foundation.org" , Paolo Bonzini , Robin Murphy , David Gibson Subject: Re: [RFC] /dev/ioasid uAPI proposal Message-ID: References: <2c62b5c7-582a-c710-0436-4ac5e8fd8b39@redhat.com> <20210604172207.GT1002214@nvidia.com> <20210604152918.57d0d369.alex.williamson@redhat.com> <20210604230108.GB1002214@nvidia.com> <20210607094148.7e2341fc.alex.williamson@redhat.com> <20210607181858.GM1002214@nvidia.com> <20210607125946.056aafa2.alex.williamson@redhat.com> <20210607190802.GO1002214@nvidia.com> <20210607134128.58c2ea31.alex.williamson@redhat.com> <12631cf3-4ef8-7c38-73bb-649d57c0226b@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12631cf3-4ef8-7c38-73bb-649d57c0226b@redhat.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 08, 2021 at 09:20:29AM +0800, Jason Wang wrote: > " > > 6.2.17 _CCA (Cache Coherency Attribute) The _CCA object returns whether or > not a bus-master device supports hardware managed cache coherency. Expected > values are 0 to indicate it is not supported, and 1 to indicate that it is > supported. All other values are reserved. > > ... > > On Intel platforms, if the _CCA object is not supplied, the OSPM will assume > the devices are hardware cache coherent. > > " _CCA is mostly used on arm/arm64 platforms to figure out if a device needs non-coherent DMA handling in the DMA API or not. It is not related to the NoSnoop TLPs that override the setting for an otherwise coherent device. 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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 1F392C11F69 for ; Wed, 30 Jun 2021 06:55:06 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 C71A061C72 for ; Wed, 30 Jun 2021 06:55:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C71A061C72 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 9156260624; Wed, 30 Jun 2021 06:55:05 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id U2A1vqtv1J5R; Wed, 30 Jun 2021 06:55:04 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 8160E606FD; Wed, 30 Jun 2021 06:55:04 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 50F31C0010; Wed, 30 Jun 2021 06:55:04 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 11F1FC000E for ; Wed, 30 Jun 2021 06:55:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id F06AA83AB2 for ; Wed, 30 Jun 2021 06:55:02 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp1.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=infradead.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Rbj6sWNbYdq7 for ; Wed, 30 Jun 2021 06:55:02 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by smtp1.osuosl.org (Postfix) with ESMTPS id 5D02683AA9 for ; Wed, 30 Jun 2021 06:55:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=f/Ss2iSM2QGOE0K5ddDAmgJLDWuc6gafnUUbn6I+ywE=; b=EjtYVsIFXW62/EkGI7hOZiVxWu WtQ1QOiJ+kE2LqSAajX/iny/lZxgDgpw4Lqlm87T+L3KdMUw9xtCm/qbkjnNm+n9HchMjHUuhlxdz w2OPufXyWbuv31Dot4DIGelHWZHewJ/p/raVKncRixUUmP7uchkRq1HvqmlhbTVJgHVFLODbv/YHA RNDQhV6qzSdLYF0g40BOD2Ta0/YGu2gzi83bR6eLmhaerMvfLzmNz8rtyEcmJ8Yhva1wvB3sNhoIm 1xB1suxXnDYbBmr21iG+4XFobuyQO+ec3qti7Yrj8KfMA7I5Z33WvXyyfut+u94vA1XrYQhuXZ2+W lhuwYjjA==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lyU6N-0050fY-DH; Wed, 30 Jun 2021 06:53:46 +0000 Date: Wed, 30 Jun 2021 07:53:39 +0100 From: Christoph Hellwig To: Jason Wang Subject: Re: [RFC] /dev/ioasid uAPI proposal Message-ID: References: <2c62b5c7-582a-c710-0436-4ac5e8fd8b39@redhat.com> <20210604172207.GT1002214@nvidia.com> <20210604152918.57d0d369.alex.williamson@redhat.com> <20210604230108.GB1002214@nvidia.com> <20210607094148.7e2341fc.alex.williamson@redhat.com> <20210607181858.GM1002214@nvidia.com> <20210607125946.056aafa2.alex.williamson@redhat.com> <20210607190802.GO1002214@nvidia.com> <20210607134128.58c2ea31.alex.williamson@redhat.com> <12631cf3-4ef8-7c38-73bb-649d57c0226b@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <12631cf3-4ef8-7c38-73bb-649d57c0226b@redhat.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Cc: Jean-Philippe Brucker , "Tian, Kevin" , "Jiang, Dave" , "Raj, Ashok" , "kvm@vger.kernel.org" , Jonathan Corbet , Robin Murphy , LKML , Kirti Wankhede , Alex Williamson , "iommu@lists.linux-foundation.org" , Jason Gunthorpe , Paolo Bonzini , David Woodhouse , David Gibson 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, Jun 08, 2021 at 09:20:29AM +0800, Jason Wang wrote: > " > > 6.2.17 _CCA (Cache Coherency Attribute) The _CCA object returns whether or > not a bus-master device supports hardware managed cache coherency. Expected > values are 0 to indicate it is not supported, and 1 to indicate that it is > supported. All other values are reserved. > > ... > > On Intel platforms, if the _CCA object is not supplied, the OSPM will assume > the devices are hardware cache coherent. > > " _CCA is mostly used on arm/arm64 platforms to figure out if a device needs non-coherent DMA handling in the DMA API or not. It is not related to the NoSnoop TLPs that override the setting for an otherwise coherent device. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu