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| -rw-r--r-- | qemu-options.hx | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/qemu-options.hx b/qemu-options.hx index 214c477dcc..0c9ddc0274 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -939,6 +939,39 @@ SRST ``-device pci-ipmi-bt,bmc=id`` Like the KCS interface, but defines a BT interface on the PCI bus. + +``-device intel-iommu[,option=...]`` + This is only supported by ``-machine q35``, which will enable Intel VT-d + emulation within the guest. It supports below options: + + ``intremap=on|off`` (default: auto) + This enables interrupt remapping feature. It's required to enable + complete x2apic. Currently it only supports kvm kernel-irqchip modes + ``off`` or ``split``, while full kernel-irqchip is not yet supported. + The default value is "auto", which will be decided by the mode of + kernel-irqchip. + + ``caching-mode=on|off`` (default: off) + This enables caching mode for the VT-d emulated device. When + caching-mode is enabled, each guest DMA buffer mapping will generate an + IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in + a synchronous way. It is required for ``-device vfio-pci`` to work + with the VT-d device, because host assigned devices requires to setup + the DMA mapping on the host before guest DMA starts. + + ``device-iotlb=on|off`` (default: off) + This enables device-iotlb capability for the emulated VT-d device. So + far virtio/vhost should be the only real user for this parameter, + paired with ats=on configured for the device. + + ``aw-bits=39|48`` (default: 39) + This decides the address width of IOVA address space. The address + space has 39 bits width for 3-level IOMMU page tables, and 48 bits for + 4-level IOMMU page tables. + + Please also refer to the wiki page for general scenarios of VT-d + emulation in QEMU: https://wiki.qemu.org/Features/VT-d. + ERST DEF("name", HAS_ARG, QEMU_OPTION_name, |