From mboxrd@z Thu Jan 1 00:00:00 1970 From: Auger Eric Subject: Re: [PATCH v3 1/7] dt-bindings: virtio-mmio: Add IOMMU description Date: Thu, 15 Nov 2018 09:45:32 +0100 Message-ID: <02c507c1-6f64-5116-756a-e0a23b32fe2a@redhat.com> References: <20181012145917.6840-1-jean-philippe.brucker@arm.com> <20181012145917.6840-2-jean-philippe.brucker@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181012145917.6840-2-jean-philippe.brucker@arm.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jean-Philippe Brucker , iommu@lists.linux-foundation.org, virtualization@lists.linux-foundation.org, devicetree@vger.kernel.org Cc: mark.rutland@arm.com, peter.maydell@linaro.org, lorenzo.pieralisi@arm.com, tnowicki@caviumnetworks.com, mst@redhat.com, marc.zyngier@arm.com, linux-pci@vger.kernel.org, will.deacon@arm.com, kvmarm@lists.cs.columbia.edu, robh+dt@kernel.org, robin.murphy@arm.com, joro@8bytes.org List-Id: devicetree@vger.kernel.org Hi Jean, On 10/12/18 4:59 PM, Jean-Philippe Brucker wrote: > The nature of a virtio-mmio node is discovered by the virtio driver at > probe time. However the DMA relation between devices must be described > statically. When a virtio-mmio node is a virtio-iommu device, it needs an > "#iommu-cells" property as specified by bindings/iommu/iommu.txt. > > Otherwise, the virtio-mmio device may perform DMA through an IOMMU, which > requires an "iommus" property. Describe these requirements in the > device-tree bindings documentation. > > Signed-off-by: Jean-Philippe Brucker > --- > .../devicetree/bindings/virtio/mmio.txt | 30 +++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/Documentation/devicetree/bindings/virtio/mmio.txt b/Documentation/devicetree/bindings/virtio/mmio.txt > index 5069c1b8e193..748595473b36 100644 > --- a/Documentation/devicetree/bindings/virtio/mmio.txt > +++ b/Documentation/devicetree/bindings/virtio/mmio.txt > @@ -8,10 +8,40 @@ Required properties: > - reg: control registers base address and size including configuration space > - interrupts: interrupt generated by the device > > +Required properties for virtio-iommu: > + > +- #iommu-cells: When the node corresponds to a virtio-iommu device, it is > + linked to DMA masters using the "iommus" or "iommu-map" > + properties [1][2]. #iommu-cells specifies the size of the > + "iommus" property. For virtio-iommu #iommu-cells must be > + 1, each cell describing a single endpoint ID. > + > +Optional properties: > + > +- iommus: If the device accesses memory through an IOMMU, it should > + have an "iommus" property [1]. Since virtio-iommu itself > + does not access memory through an IOMMU, the "virtio,mmio" > + node cannot have both an "#iommu-cells" and an "iommus" > + property. > + > Example: > > virtio_block@3000 { > compatible = "virtio,mmio"; > reg = <0x3000 0x100>; > interrupts = <41>; > + > + /* Device has endpoint ID 23 */ > + iommus = <&viommu 23> > } > + > + viommu: virtio_iommu@3100 { > + compatible = "virtio,mmio"; > + reg = <0x3100 0x100>; > + interrupts = <42>; > + > + #iommu-cells = <1> > + } > + > +[1] Documentation/devicetree/bindings/iommu/iommu.txt > +[2] Documentation/devicetree/bindings/pci/pci-iommu.txt > Reviewed-by: Eric Auger Thanks Eric 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 917EEC43441 for ; Thu, 15 Nov 2018 08:45:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59E43223DD for ; Thu, 15 Nov 2018 08:45:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59E43223DD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-pci-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728605AbeKOSwb (ORCPT ); Thu, 15 Nov 2018 13:52:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50486 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728527AbeKOSwa (ORCPT ); Thu, 15 Nov 2018 13:52:30 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D0BE3A833A; Thu, 15 Nov 2018 08:45:37 +0000 (UTC) Received: from [10.36.116.180] (ovpn-116-180.ams2.redhat.com [10.36.116.180]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ADEC617B4F; Thu, 15 Nov 2018 08:45:33 +0000 (UTC) Subject: Re: [PATCH v3 1/7] dt-bindings: virtio-mmio: Add IOMMU description To: Jean-Philippe Brucker , iommu@lists.linux-foundation.org, virtualization@lists.linux-foundation.org, devicetree@vger.kernel.org Cc: linux-pci@vger.kernel.org, kvmarm@lists.cs.columbia.edu, peter.maydell@linaro.org, joro@8bytes.org, mst@redhat.com, jasowang@redhat.com, robh+dt@kernel.org, mark.rutland@arm.com, tnowicki@caviumnetworks.com, kevin.tian@intel.com, marc.zyngier@arm.com, robin.murphy@arm.com, will.deacon@arm.com, lorenzo.pieralisi@arm.com References: <20181012145917.6840-1-jean-philippe.brucker@arm.com> <20181012145917.6840-2-jean-philippe.brucker@arm.com> From: Auger Eric Message-ID: <02c507c1-6f64-5116-756a-e0a23b32fe2a@redhat.com> Date: Thu, 15 Nov 2018 09:45:32 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181012145917.6840-2-jean-philippe.brucker@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 15 Nov 2018 08:45:38 +0000 (UTC) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi Jean, On 10/12/18 4:59 PM, Jean-Philippe Brucker wrote: > The nature of a virtio-mmio node is discovered by the virtio driver at > probe time. However the DMA relation between devices must be described > statically. When a virtio-mmio node is a virtio-iommu device, it needs an > "#iommu-cells" property as specified by bindings/iommu/iommu.txt. > > Otherwise, the virtio-mmio device may perform DMA through an IOMMU, which > requires an "iommus" property. Describe these requirements in the > device-tree bindings documentation. > > Signed-off-by: Jean-Philippe Brucker > --- > .../devicetree/bindings/virtio/mmio.txt | 30 +++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/Documentation/devicetree/bindings/virtio/mmio.txt b/Documentation/devicetree/bindings/virtio/mmio.txt > index 5069c1b8e193..748595473b36 100644 > --- a/Documentation/devicetree/bindings/virtio/mmio.txt > +++ b/Documentation/devicetree/bindings/virtio/mmio.txt > @@ -8,10 +8,40 @@ Required properties: > - reg: control registers base address and size including configuration space > - interrupts: interrupt generated by the device > > +Required properties for virtio-iommu: > + > +- #iommu-cells: When the node corresponds to a virtio-iommu device, it is > + linked to DMA masters using the "iommus" or "iommu-map" > + properties [1][2]. #iommu-cells specifies the size of the > + "iommus" property. For virtio-iommu #iommu-cells must be > + 1, each cell describing a single endpoint ID. > + > +Optional properties: > + > +- iommus: If the device accesses memory through an IOMMU, it should > + have an "iommus" property [1]. Since virtio-iommu itself > + does not access memory through an IOMMU, the "virtio,mmio" > + node cannot have both an "#iommu-cells" and an "iommus" > + property. > + > Example: > > virtio_block@3000 { > compatible = "virtio,mmio"; > reg = <0x3000 0x100>; > interrupts = <41>; > + > + /* Device has endpoint ID 23 */ > + iommus = <&viommu 23> > } > + > + viommu: virtio_iommu@3100 { > + compatible = "virtio,mmio"; > + reg = <0x3100 0x100>; > + interrupts = <42>; > + > + #iommu-cells = <1> > + } > + > +[1] Documentation/devicetree/bindings/iommu/iommu.txt > +[2] Documentation/devicetree/bindings/pci/pci-iommu.txt > Reviewed-by: Eric Auger Thanks Eric