From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
To: iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
devicetree@vger.kernel.org,
virtualization@lists.linux-foundation.org,
virtio-dev@lists.oasis-open.org, joro@8bytes.org, mst@redhat.com
Cc: jasowang@redhat.com, robh+dt@kernel.org, mark.rutland@arm.com,
bhelgaas@google.com, frowand.list@gmail.com,
kvmarm@lists.cs.columbia.edu, eric.auger@redhat.com,
tnowicki@caviumnetworks.com, kevin.tian@intel.com,
marc.zyngier@arm.com, robin.murphy@arm.com, will.deacon@arm.com,
lorenzo.pieralisi@arm.com, bharat.bhushan@nxp.com
Subject: [PATCH v7 2/7] dt-bindings: virtio: Add virtio-pci-iommu node
Date: Tue, 15 Jan 2019 12:19:54 +0000 [thread overview]
Message-ID: <20190115121959.23763-3-jean-philippe.brucker@arm.com> (raw)
In-Reply-To: <20190115121959.23763-1-jean-philippe.brucker@arm.com>
Some systems implement virtio-iommu as a PCI endpoint. The operating
system needs to discover the relationship between IOMMU and masters long
before the PCI endpoint gets probed. Add a PCI child node to describe the
virtio-iommu device.
The virtio-pci-iommu is conceptually split between a PCI programming
interface and a translation component on the parent bus. The latter
doesn't have a node in the device tree. The virtio-pci-iommu node
describes both, by linking the PCI endpoint to "iommus" property of DMA
master nodes and to "iommu-map" properties of bus nodes.
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/iommu.txt | 66 +++++++++++++++++++
1 file changed, 66 insertions(+)
create mode 100644 Documentation/devicetree/bindings/virtio/iommu.txt
diff --git a/Documentation/devicetree/bindings/virtio/iommu.txt b/Documentation/devicetree/bindings/virtio/iommu.txt
new file mode 100644
index 000000000000..2407fea0651c
--- /dev/null
+++ b/Documentation/devicetree/bindings/virtio/iommu.txt
@@ -0,0 +1,66 @@
+* virtio IOMMU PCI device
+
+When virtio-iommu uses the PCI transport, its programming interface is
+discovered dynamically by the PCI probing infrastructure. However the
+device tree statically describes the relation between IOMMU and DMA
+masters. Therefore, the PCI root complex that hosts the virtio-iommu
+contains a child node representing the IOMMU device explicitly.
+
+Required properties:
+
+- compatible: Should be "virtio,pci-iommu"
+- reg: PCI address of the IOMMU. As defined in the PCI Bus
+ Binding reference [1], the reg property is a five-cell
+ address encoded as (phys.hi phys.mid phys.lo size.hi
+ size.lo). phys.hi should contain the device's BDF as
+ 0b00000000 bbbbbbbb dddddfff 00000000. The other cells
+ should be zero.
+- #iommu-cells: Each platform DMA master managed by the IOMMU is assigned
+ an endpoint ID, described by the "iommus" property [2].
+ For virtio-iommu, #iommu-cells must be 1.
+
+Notes:
+
+- DMA from the IOMMU device isn't managed by another IOMMU. Therefore the
+ virtio-iommu node doesn't have an "iommus" property, and is omitted from
+ the iommu-map property of the root complex.
+
+Example:
+
+pcie@10000000 {
+ compatible = "pci-host-ecam-generic";
+ ...
+
+ /* The IOMMU programming interface uses slot 00:01.0 */
+ iommu0: iommu@0008 {
+ compatible = "virtio,pci-iommu";
+ reg = <0x00000800 0 0 0 0>;
+ #iommu-cells = <1>;
+ };
+
+ /*
+ * The IOMMU manages all functions in this PCI domain except
+ * itself. Omit BDF 00:01.0.
+ */
+ iommu-map = <0x0 &iommu0 0x0 0x8>
+ <0x9 &iommu0 0x9 0xfff7>;
+};
+
+pcie@20000000 {
+ compatible = "pci-host-ecam-generic";
+ ...
+ /*
+ * The IOMMU also manages all functions from this domain,
+ * with endpoint IDs 0x10000 - 0x1ffff
+ */
+ iommu-map = <0x0 &iommu0 0x10000 0x10000>;
+};
+
+ethernet@fe001000 {
+ ...
+ /* The IOMMU manages this platform device with endpoint ID 0x20000 */
+ iommus = <&iommu0 0x20000>;
+};
+
+[1] Documentation/devicetree/bindings/pci/pci.txt
+[2] Documentation/devicetree/bindings/iommu/iommu.txt
--
2.19.1
next prev parent reply other threads:[~2019-01-15 12:25 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 12:19 [PATCH v7 0/7] Add virtio-iommu driver Jean-Philippe Brucker
2019-01-15 12:19 ` [PATCH v7 1/7] dt-bindings: virtio-mmio: Add IOMMU description Jean-Philippe Brucker
2019-01-15 12:19 ` Jean-Philippe Brucker [this message]
2019-01-15 12:19 ` [PATCH v7 3/7] of: Allow the iommu-map property to omit untranslated devices Jean-Philippe Brucker
2019-01-15 12:19 ` [PATCH v7 4/7] PCI: OF: Initialize dev->fwnode appropriately Jean-Philippe Brucker
2019-01-15 12:19 ` [PATCH v7 5/7] iommu: Add virtio-iommu driver Jean-Philippe Brucker
2019-01-15 12:19 ` [PATCH v7 6/7] iommu/virtio: Add probe request Jean-Philippe Brucker
2019-01-15 12:19 ` [PATCH v7 7/7] iommu/virtio: Add event queue Jean-Philippe Brucker
2019-01-18 15:51 ` [PATCH v7 0/7] Add virtio-iommu driver Michael S. Tsirkin
2019-01-21 11:29 ` Jean-Philippe Brucker
2019-01-29 18:54 ` Michael S. Tsirkin
2019-02-21 21:57 ` Thiago Jung Bauermann
2019-01-23 8:34 ` Joerg Roedel
2019-01-24 16:03 ` Jean-Philippe Brucker
2019-02-21 22:18 ` Thiago Jung Bauermann
2019-02-22 12:18 ` Jean-Philippe Brucker
2019-02-25 13:20 ` Tomasz Nowicki
2019-05-12 16:31 ` Michael S. Tsirkin
2019-05-27 9:26 ` Joerg Roedel
2019-05-27 15:15 ` Michael S. Tsirkin
2019-05-28 9:18 ` Jean-Philippe Brucker
2019-05-12 17:15 ` Michael S. Tsirkin
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