[PATCH v4 8/8] qemu-options.hx: Document arm-smmuv3 device's accel properties

[Nathan Chen <nathanc@nvidia.com>]

From: Nathan Chen <nathanc@nvidia.com>

Document arm-smmuv3 properties for setting HW-acceleration,
Range Invalidation, and Address Translation Services support, as
well as setting Output Address size and Substream ID size.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Shameer Kolothum <skolothumtho@nvidia.com>
Signed-off-by: Nathan Chen <nathanc@nvidia.com>
---
 qemu-options.hx | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 69e5a874c1..f8da35513a 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1279,13 +1279,43 @@ SRST
     ``aw-bits=val`` (val between 32 and 64, default depends on machine)
         This decides the address width of the IOVA address space.
 
-``-device arm-smmuv3,primary-bus=id``
+``-device arm-smmuv3,primary-bus=id[,option=...]``
     This is only supported by ``-machine virt`` (ARM).
 
     ``primary-bus=id``
         Accepts either the default root complex (pcie.0) or a
         pxb-pcie based root complex.
 
+    ``accel=on|off`` (default: off)
+        Enables guest to leverage host SMMUv3 features for acceleration.
+        Enabling accel configures the host SMMUv3 in nested mode to support
+        vfio-pci passthrough.
+
+     The following options are available when accel=on.
+     Note: 'auto' mode is not currently supported.
+
+    ``ril=on|off`` (default: on)
+        Support for Range Invalidation, which allows the SMMUv3 driver to
+        invalidate TLB entries for a range of IOVAs at once instead of issuing
+        separate commands to invalidate each page. Must match with host SMMUv3
+        Range Invalidation support.
+
+    ``ats=on|off`` (default: off)
+        Support for Address Translation Services, which enables PCIe devices to
+        cache address translations in their local TLB and reduce latency. Host
+        SMMUv3 must support ATS in order to enable this feature for the vIOMMU.
+
+    ``oas=val`` (supported values are 44 and 48. default: 44)
+        Sets the Output Address Size in bits. The value set here must be less
+        than or equal to the host SMMUv3's supported OAS, so that the
+        intermediate physical addresses (IPA) consumed by host SMMU for stage-2
+        translation do not exceed the host's max supported IPA size.
+
+    ``ssidsize=val`` (val between 0 and 20. default: 0)
+        Sets the Substream ID size in bits. When set to a non-zero value,
+        PASID capability is advertised to the vIOMMU and accelerated use cases
+        such as Shared Virtual Addressing (SVA) are supported.
+
 ``-device amd-iommu[,option=...]``
     Enables emulation of an AMD-Vi I/O Memory Management Unit (IOMMU).
     Only available with ``-machine q35``, it supports the following options:
-- 
2.43.0