4a97ecd040
- qemu_migration: Refactor qemuMigrationSrcRestoreDomainState (RHEL-79168) - qemu_migration: Do not automatically resume domain after I/O error (RHEL-79168) - qemucapabilitiestest: Add data for the qemu-10.0 dev cycle on x86_64 (RHEL-79095) - qemucapabilitiestest: Update 'caps_10.0.0_x86_64' to 'v9.2.0-1636-gffaf7f0376' (RHEL-79095) - qemu: capabilies: Introduce QEMU_CAPS_BLOCKDEV_SET_ACTIVE (RHEL-79095) - qemu: monitor: Add monitor backend for 'blockdev-set-active' (RHEL-79095) - qemu: migration: Reactivate block nodes after migration if VM is left paused (RHEL-79095) - conf: change virDomainHostdevInsert() to return void (RHEL-69455) - qemu: fix qemu validation to forbid guest-side IP address for type='vdpa' (RHEL-69455) - qemu: validate that model is virtio for vhostuser and vdpa interfaces in the same place (RHEL-69455) - qemu: automatically set model type='virtio' for interface type='vhostuser' (RHEL-69455) - qemu: do all vhostuser attribute validation in qemu driver (RHEL-69455) - conf/qemu: make <source> element *almost* optional for type=vhostuser (RHEL-69455) - qemu: use switch instead of if in qemuProcessPrepareDomainNetwork() (RHEL-69455) - qemu: make qemuPasstCreateSocketPath() public (RHEL-69455) - qemu: complete vhostuser + passt support (RHEL-69455) - qemu: fail validation if a domain def has vhostuser/passt but no shared mem (RHEL-69455) - docs: improve type='user' docs to higlight differences between SLIRP and passt (RHEL-69455) - docs: document using passt backend with <interface type='vhostuser'> (RHEL-69455) - utils: Canonicalize paths before comparing them (RHEL-79166) Resolves: RHEL-69455, RHEL-79095, RHEL-79166, RHEL-79168
140 lines
6.2 KiB
Diff
140 lines
6.2 KiB
Diff
From 3bcec68251696b1255be7dc2504378b927ef5123 Mon Sep 17 00:00:00 2001
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Message-ID: <3bcec68251696b1255be7dc2504378b927ef5123.1739824250.git.jdenemar@redhat.com>
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From: Laine Stump <laine@redhat.com>
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Date: Fri, 14 Feb 2025 23:35:56 -0500
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Subject: [PATCH] docs: document using passt backend with <interface
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type='vhostuser'>
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Almost everything is already there (in the section for using passt
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with type='user'), so we just need to point to that from the
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type='vhostuser' section (and vice versa), and add a bit of glue.
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Also updated a few related details that have changed (e.g. default
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model type for vhostuser is now 'virtio', and source type/mode are now
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optional), and changed "vhost-user interface" to "vhost-user
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connection" because the interface is a virtio interface, and
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vhost-user is being used to connect that interface to the outside.
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Signed-off-by: Laine Stump <laine@redhat.com>
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Reviewed-by: Ján Tomko <jtomko@redhat.com>
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(cherry picked from commit 96fd17a99b514e585a94d43d40ab9a74907c7a5b)
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https://issues.redhat.com/browse/RHEL-69455
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Signed-off-by: Laine Stump <laine@redhat.com>
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---
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docs/formatdomain.rst | 73 ++++++++++++++++++++++++++++++++++++-------
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1 file changed, 62 insertions(+), 11 deletions(-)
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diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
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index 577366b934..c077c09a39 100644
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--- a/docs/formatdomain.rst
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+++ b/docs/formatdomain.rst
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@@ -5131,6 +5131,15 @@ destined for the host toward the guest instead), and a socket between
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passt and QEMU forwards that traffic on to the guest (and back out,
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of course).
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+*(:since:`Since 11.1.0 (QEMU and KVM only)` you may prefer to use the
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+passt backend with the more efficient and performant type='vhostuser'
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+rather than type='user'. All the options related to passt in the
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+paragraphs below here also apply when using the passt backend with
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+type='vhostuser'; any other details specific to vhostuser are
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+described* `here
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+<formatdomain.html#vhost-user-connection-with-passt-backend>`__.)
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+
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+
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Similar to SLIRP, passt has an internal DHCP server that provides a
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requesting guest with one ipv4 and one ipv6 address. There are default
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values for both of these, or you can use the ``<ip>`` element
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@@ -5823,7 +5832,7 @@ following attributes are available for the ``virtio`` NIC driver:
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The optional ``queues`` attribute controls the number of queues to be used
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for either `Multiqueue
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virtio-net <https://www.linux-kvm.org/page/Multiqueue>`__ or vhost-user (See
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- `vhost-user interface`_) network interfaces. Use of multiple packet
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+ `vhost-user connection`_) network interfaces. Use of multiple packet
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processing queues requires the interface having the
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``<model type='virtio'/>`` element. Each queue will potentially be handled by
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a different processor, resulting in much higher throughput.
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@@ -6267,8 +6276,8 @@ similarly named elements used to configure the guest side of the interface
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(described above).
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-vhost-user interface
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-^^^^^^^^^^^^^^^^^^^^
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+vhost-user connection
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+^^^^^^^^^^^^^^^^^^^^^
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:since:`Since 1.2.7` the vhost-user enables the communication between a QEMU
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virtual machine and other userspace process using the Virtio transport protocol.
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@@ -6295,16 +6304,58 @@ plane is based on shared memory.
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</devices>
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...
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-The ``<source>`` element has to be specified along with the type of char device.
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-Currently, only type='unix' is supported, where the path (the directory path of
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-the socket) and mode attributes are required. Both ``mode='server'`` and
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-``mode='client'`` are supported. vhost-user requires the virtio model type, thus
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-the ``<model>`` element is mandatory. :since:`Since 4.1.0` the element has an
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-optional child element ``reconnect`` which configures reconnect timeout if the
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-connection is lost. It has two attributes ``enabled`` (which accepts ``yes`` and
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-``no``) and ``timeout`` which specifies the amount of seconds after which
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+The ``<source>`` element has to be specified along with the type of
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+char device. Currently, only type='unix' is supported, where the path
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+(the directory path of the socket) and mode attributes are
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+required. Both ``mode='server'`` and ``mode='client'`` are
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+supported. (:since:`Since 11.1.0` the default source type for
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+vhostuser interfaces is 'unix' and default mode is 'client', so those
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+two attributes are now optional).
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+
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+The vhost-user protocol only works with the virtio guest driver, so
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+the ``<model>`` element ``type`` attribute is mandatory (:since:`Since
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+11.1.0` the default model type for vhostuser interfaces is now
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+'virtio' so ``<model>`` is no longer mandatory). :since:`Since 4.1.0`
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+the ``<source>`` element has an optional child element ``reconnect``
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+which configures reconnect timeout if the connection is lost. It has
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+two attributes ``enabled`` (which accepts ``yes`` and ``no``) and
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+``timeout`` which specifies the amount of seconds after which
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hypervisor tries to reconnect.
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+
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+vhost-user connection with passt backend
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+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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+
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+:since:`Since 11.1.0 (QEMU and KVM only)` passt can be used as the
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+other end of the vhost-user connection. This is a compelling
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+alternative, because passt provides all of its network connectivity
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+without requiring any elevated privileges or capabilities, and
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+vhost-user uses shared memory to make this unprivileged connection
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+very high performance as well. You can set a type='vhostuser'
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+interface to use passt as the backend by adding ``<backend
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+type='passt'/>``. When passt is the backend, only a single driver
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+queue is supported, and the ``<source>`` path/type/mode are all
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+implied to be "matching the passt process" so **must not** be
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+specified. All of the passt options `described here
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+<formatdomain.html#userspace-connection-using-passt>`__, are also
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+supported for ``type='vhostuser'`` with the passt backend, e.g.
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+setting guest-side IP addresses with ``<ip>`` and port forwarding with
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+``<portForward``.
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+
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+::
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+
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+ ...
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+ <devices>
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+ <interface type='vhostuser'>
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+ <backend type='passt'/>
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+ <mac address='52:54:00:3b:83:1a'/>
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+ <source dev='enp1s0'/>
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+ <ip address='10.30.0.5 prefix='24'/>
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+ </interface>
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+ </devices>
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+ ...
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+
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+
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Traffic filtering with NWFilter
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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--
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2.48.1
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