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| author | Akihiko Odaki <akihiko.odaki@daynix.com> | 2024-07-15 14:19:14 +0900 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2024-07-22 20:15:41 -0400 |
| commit | d6f40c95b35bd380340b698e4306704fe22a5d68 (patch) | |
| tree | 872d4371c5ab06cf88097cd02a694cf8662fcae9 /docs | |
| parent | c2d6db6a1f39780b24538440091893f9fbe060a7 (diff) | |
docs: Document composable SR-IOV device
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20240715-sriov-v5-8-3f5539093ffc@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/system/index.rst | 1 | ||||
| -rw-r--r-- | docs/system/sriov.rst | 36 |
2 files changed, 37 insertions, 0 deletions
diff --git a/docs/system/index.rst b/docs/system/index.rst index c21065e519..718e9d3c56 100644 --- a/docs/system/index.rst +++ b/docs/system/index.rst @@ -39,3 +39,4 @@ or Hypervisor.Framework. multi-process confidential-guest-support vm-templating + sriov diff --git a/docs/system/sriov.rst b/docs/system/sriov.rst new file mode 100644 index 0000000000..a851a66a4b --- /dev/null +++ b/docs/system/sriov.rst @@ -0,0 +1,36 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +Compsable SR-IOV device +======================= + +SR-IOV (Single Root I/O Virtualization) is an optional extended capability of a +PCI Express device. It allows a single physical function (PF) to appear as +multiple virtual functions (VFs) for the main purpose of eliminating software +overhead in I/O from virtual machines. + +There are devices with predefined SR-IOV configurations, but it is also possible +to compose an SR-IOV device yourself. Composing an SR-IOV device is currently +only supported by virtio-net-pci. + +Users can configure an SR-IOV-capable virtio-net device by adding +virtio-net-pci functions to a bus. Below is a command line example: + +.. code-block:: shell + + -netdev user,id=n -netdev user,id=o + -netdev user,id=p -netdev user,id=q + -device pcie-root-port,id=b + -device virtio-net-pci,bus=b,addr=0x0.0x3,netdev=q,sriov-pf=f + -device virtio-net-pci,bus=b,addr=0x0.0x2,netdev=p,sriov-pf=f + -device virtio-net-pci,bus=b,addr=0x0.0x1,netdev=o,sriov-pf=f + -device virtio-net-pci,bus=b,addr=0x0.0x0,netdev=n,id=f + +The VFs specify the paired PF with ``sriov-pf`` property. The PF must be +added after all VFs. It is the user's responsibility to ensure that VFs have +function numbers larger than one of the PF, and that the function numbers +have a consistent stride. + +You may also need to perform additional steps to activate the SR-IOV feature on +your guest. For Linux, refer to [1]_. + +.. [1] https://docs.kernel.org/PCI/pci-iov-howto.html |