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Diffstat (limited to 'docs/system/devices/vdpa-net.rst')
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diff --git a/docs/system/devices/vdpa-net.rst b/docs/system/devices/vdpa-net.rst new file mode 100644 index 0000000000..323d8c926a --- /dev/null +++ b/docs/system/devices/vdpa-net.rst @@ -0,0 +1,121 @@ +vdpa net +============ + +This document explains the setup and usage of the vdpa network device. +The vdpa network device is a paravirtualized vdpa emulate device. + +Description +----------- + +VDPA net devices support dirty page bitmap mark and vring state saving and recovery. + +Users can use this VDPA device for live migration simulation testing in a nested virtualization environment. + +Registers layout +---------------- + +The vdpa device add live migrate registers layout as follow:: + + Offset Register Name Bitwidth Associated vq + 0x0 LM_LOGGING_CTRL 4bits + 0x10 LM_BASE_ADDR_LOW 32bits + 0x14 LM_BASE_ADDR_HIGH 32bits + 0x18 LM_END_ADDR_LOW 32bits + 0x1c LM_END_ADDR_HIGH 32bits + 0x20 LM_RING_STATE_OFFSET 32bits vq0 + 0x24 LM_RING_STATE_OFFSET 32bits vq1 + 0x28 LM_RING_STATE_OFFSET 32bits vq2 + ...... + 0x20+1023*4 LM_RING_STATE_OFFSET 32bits vq1023 + +These registers are extended at the end of the notify bar space. + +Architecture diagram +-------------------- +:: + + |------------------------------------------------------------------------| + | guest-L1-user-space | + | | + | |----------------------------------------| + | | [virtio-net driver] | + | | ^ guest-L2-src(iommu=on) | + | |--------------|-------------------------| + | | | qemu-L2-src(viommu) | + | [dpdk-vdpa]<->[vhost socket]<-+->[vhost-user backend(iommu=on)] | + -------------------------------------------------------------------------- + -------------------------------------------------------------------------- + | ^ guest-L1-kernel-space | + | | | + | [VFIO] | + | ^ | + | | guest-L1-src(iommu=on) | + --------|----------------------------------------------------------------- + --------|----------------------------------------------------------------- + | [vdpa net device(iommu=on)] [manager nic device] | + | | | | + | | | | + | [tap device] qemu-L1-src(viommu) | | + ------------------------------------------------+------------------------- + | + | + --------------------- | + | kernel net bridge |<----- + | virbr0 |<---------------------------------- + --------------------- | + | + | + -------------------------------------------------------------------------- | + | guest-L1-user-space | | + | | | + | |----------------------------------------| | + | | [virtio-net driver] | | + | | ^ guest-L2-dst(iommu=on) | | + | |--------------|-------------------------| | + | | | qemu-L2-dst(viommu) | | + | [dpdk-vdpa]<->[vhost socket]<-+->[vhost-user backend(iommu=on)] | | + -------------------------------------------------------------------------- | + -------------------------------------------------------------------------- | + | ^ guest-L1-kernel-space | | + | | | | + | [VFIO] | | + | ^ | | + | | guest-L1-dst(iommu=on) | | + --------|----------------------------------------------------------------- | + --------|----------------------------------------------------------------- | + | [vdpa net device(iommu=on)] [manager nic device]----------------+---- + | | | + | | | + | [tap device] qemu-L1-dst(viommu) | + -------------------------------------------------------------------------- + + +Device properties +----------------- + +The Virtio vdpa device can be configured with the following properties: + + * ``vdpa=on`` open vdpa device emulated. + +Usages +-------- +This patch add virtio sriov support and vdpa live migrate support. +You can open vdpa by set xml file as follow:: + + <qemu:commandline xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'> + <qemu:arg value='-device'/> + <qemu:arg value='intel-iommu,intremap=on,device-iotlb=on,aw-bits=48'/> + <qemu:arg value='-netdev'/> + <qemu:arg value='tap,id=hostnet1,script=no,downscript=no,vhost=off'/> + <qemu:arg value='-device'/> + <qemu:arg value='virtio-net-pci,netdev=hostnet1,id=net1,mac=56:4a:b7:4f:4d:a9,bus=pci.6,addr=0x0,iommu_platform=on,ats=on,vdpa=on'/> + </qemu:commandline> + +Limitations +----------- +1. Dependent on tap device with param ``vhost=off``. +2. Nested virtualization environment only supports ``q35`` machines. +3. Current only support split vring live migrate. + + + |