From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
To: joro@8bytes.org, mst@redhat.com
Cc: mark.rutland@arm.com, virtio-dev@lists.oasis-open.org,
kevin.tian@intel.com, tnowicki@caviumnetworks.com,
frowand.list@gmail.com, devicetree@vger.kernel.org,
linux-pci@vger.kernel.org, jasowang@redhat.com,
virtualization@lists.linux-foundation.org,
iommu@lists.linux-foundation.org, robh+dt@kernel.org,
bhelgaas@google.com, robin.murphy@arm.com,
kvmarm@lists.cs.columbia.edu
Subject: [PATCH v8 1/7] dt-bindings: virtio-mmio: Add IOMMU description
Date: Thu, 30 May 2019 18:09:23 +0100 [thread overview]
Message-ID: <20190530170929.19366-2-jean-philippe.brucker@arm.com> (raw)
In-Reply-To: <20190530170929.19366-1-jean-philippe.brucker@arm.com>
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.
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
---
.../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..21af30fbb81f 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: 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
--
2.21.0
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-05-30 17:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 17:09 [PATCH v8 0/7] Add virtio-iommu driver Jean-Philippe Brucker
2019-05-30 17:09 ` Jean-Philippe Brucker [this message]
2019-05-30 17:09 ` [PATCH v8 2/7] dt-bindings: virtio: Add virtio-pci-iommu node Jean-Philippe Brucker
2019-05-30 17:45 ` Michael S. Tsirkin
2019-05-31 11:13 ` [virtio-dev] " Jean-Philippe Brucker
2019-06-16 20:04 ` Michael S. Tsirkin
2019-05-30 17:09 ` [PATCH v8 3/7] of: Allow the iommu-map property to omit untranslated devices Jean-Philippe Brucker
2019-05-30 17:09 ` [PATCH v8 4/7] PCI: OF: Initialize dev->fwnode appropriately Jean-Philippe Brucker
2019-05-30 17:09 ` [PATCH v8 5/7] iommu: Add virtio-iommu driver Jean-Philippe Brucker
2019-06-14 7:33 ` Auger Eric
2019-05-30 17:09 ` [PATCH v8 6/7] iommu/virtio: Add probe request Jean-Philippe Brucker
2019-05-30 17:09 ` [PATCH v8 7/7] iommu/virtio: Add event queue Jean-Philippe Brucker
2019-06-13 15:54 ` [PATCH v8 0/7] Add virtio-iommu driver Auger Eric
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