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hw/virtio: Add support for VDPA network simulation devices

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This patch adds support for VDPA network simulation devices.
The device is developed based on virtio-net and tap backend,
and supports hardware live migration function.

For more details, please refer to "docs/system/devices/vdpa-net.rst"

Signed-off-by: Hao Chen <chenh@yusur.tech>
Message-Id: <20240221073802.2888022-1-chenh@yusur.tech>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Hao Chen 2024-02-21 15:38:02 +08:00 • committed by Michael S. Tsirkin
parent 043e127a12
commit cd341fd1ff
9 changed files with 399 additions and 3 deletions
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1
docs/system/device-emulation.rst
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@ -99,3 +99,4 @@ Emulated Devices
devices/canokey.rst
devices/usb-u2f.rst
devices/igb.rst
devices/vdpa-net.rst

121
docs/system/devices/vdpa-net.rst Normal file
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@ -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.