7:10 a.m.
Signed-off-by: Peter Krempa <pkrempa(a)redhat.com>
---
docs/formatdomain.rst | 20 +-
docs/formatdomaincaps.html.in | 693 ----------------------------------
docs/formatdomaincaps.rst | 602 +++++++++++++++++++++++++++++
docs/kbase/backing_chains.rst | 2 +-
docs/meson.build | 2 +-
5 files changed, 614 insertions(+), 705 deletions(-)
delete mode 100644 docs/formatdomaincaps.html.in
create mode 100644 docs/formatdomaincaps.rst
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 95ace2677e..2dc52baa14 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -1406,15 +1406,15 @@ In case no restrictions need to be put on CPU model and its
features, a simpler
expected. :since:`Since 3.2.0 and QEMU 2.9.0` this mode works the way it
was designed and it is indicated by the ``fallback`` attribute set to
``forbid`` in the host-model CPU definition advertised in `domain
- capabilities XML <formatdomaincaps.html#elementsCPU>`__. When ``fallback``
- attribute is set to ``allow`` in the domain capabilities XML, it is
- recommended to use ``custom`` mode with just the CPU model from the host
- capabilities XML. :since:`Since 1.2.11` PowerISA allows processors to run
- VMs in binary compatibility mode supporting an older version of ISA.
- Libvirt on PowerPC architecture uses the ``host-model`` to signify a guest
- mode CPU running in binary compatibility mode. Example: When a user needs
- a power7 VM to run in compatibility mode on a Power8 host, this can be
- described in XML as follows :
+ capabilities XML <formatdomaincaps.html#cpu-configuration>`__. When
+ ``fallback`` attribute is set to ``allow`` in the domain capabilities
+ XML, it is recommended to use ``custom`` mode with just the CPU model
+ from the host capabilities XML. :since:`Since 1.2.11` PowerISA allows
+ processors to run VMs in binary compatibility mode supporting an older
+ version of ISA. Libvirt on PowerPC architecture uses the ``host-model``
+ to signify a guest mode CPU running in binary compatibility mode.
+ Example: When a user needs a power7 VM to run in compatibility mode on a
+ Power8 host, this can be described in XML as follows :
::
@@ -2902,7 +2902,7 @@ paravirtualized driver is specified via the ``disk`` element.
This element describes the backing store used by the disk specified by
sibling ``source`` element. :since:`Since 1.2.4.` If the hypervisor driver
does not support the
- `backingStoreInput <formatdomaincaps.html#featureBackingStoreInput>`__ (
+ `backingStoreInput <formatdomaincaps.html#backingstoreinput>`__ (
:since:`Since 5.10.0` ) domain feature the ``backingStore`` is ignored on
input and only used for output to describe the detected backing chains of
running domains. If ``backingStoreInput`` is supported the ``backingStore``
diff --git a/docs/formatdomaincaps.html.in b/docs/formatdomaincaps.html.in
deleted file mode 100644
index 35b8bf3def..0000000000
--- a/docs/formatdomaincaps.html.in
+++ /dev/null
@@ -1,693 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE html>
-<html xmlns="http://www.w3.org/1999/xhtml">
- <body>
- <h1>Domain capabilities XML format</h1>
-
- <ul id="toc"></ul>
-
- <h2><a id="Overview">Overview</a></h2>
-
- <p>Sometimes, when a new domain is to be created it may come handy to know
- the capabilities of the hypervisor so the correct combination of devices and
- drivers is used. For example, when management application is considering the
- mode for a host device's passthrough there are several options depending not
- only on host, but on hypervisor in question too. If the hypervisor is qemu
- then it needs to be more recent to support VFIO, while legacy KVM is
- achievable just fine with older qemus.</p>
-
- <p>The main difference between
- <a
href="/html/libvirt-libvirt-host.html#virConnectGetCapabilities">
- <code>virConnectGetCapabilities</code>
- </a>
- and the emulator capabilities API is, the former one aims more on
- the host capabilities (e.g. NUMA topology, security models in
- effect, etc.) while the latter one specializes on the hypervisor
- capabilities.</p>
-
- <p>While the <a href="formatcaps.html">Driver
Capabilities</a> provides the
- host capabilities (e.g NUMA topology, security models in effect, etc.), the
- Domain Capabilities provides the hypervisor specific capabilities for
- Management Applications to query and make decisions regarding what to
- utilize.</p>
-
- <p>The Domain Capabilities can provide information such as the correct
- combination of devices and drivers that are supported. Knowing which host
- and hypervisor specific options are available or supported would allow the
- management application to choose an appropriate mode for a pass-through
- host device as well as which adapter to utilize.</p>
-
- <p>Some XML elements may be entirely omitted from the domaincapabilities
- XML, depending on what the libvirt driver has filled in. Applications
- should only act on what is explicitly reported in the domaincapabilities
- XML. For example, if <disk supported='yes'/> is present, you
can safely
- assume the driver supports <disk> devices. If <disk
supported='no'/> is
- present, you can safely assume the driver does NOT support <disk>
- devices. If the <disk> block is omitted entirely, the driver is not
- indicating one way or the other whether it supports <disk> devices,
and
- applications should not interpret the missing block to mean any thing in
- particular.</p>
-
- <h2><a id="elements">Element and attribute
overview</a></h2>
-
- <p> A new query interface was added to the virConnect API's to retrieve
the
- XML listing of the set of domain capabilities (<span
class="since">Since
- 1.2.7</span>):</p>
-
-<pre>
-<a
href="/html/libvirt-libvirt-domain.html#virConnectGetDomainCapabilities">virConnectGetDomainCapabilities</a>
-</pre>
-
- <p>The root element that emulator capability XML document starts with has
- name <code>domainCapabilities</code>. It contains at least four direct
- child elements:</p>
-
-<pre>
-<domainCapabilities>
- <path>/usr/bin/qemu-system-x86_64</path>
- <domain>kvm</domain>
- <machine>pc-i440fx-2.1</machine>
- <arch>x86_64</arch>
- ...
-</domainCapabilities>
-</pre>
- <dl>
- <dt><code>path</code></dt>
- <dd>The full path to the emulator binary.</dd>
-
- <dt><code>domain</code></dt>
- <dd>Describes the <a
href="formatdomain.html#elements">virtualization
- type</a> (or so called domain type).</dd>
-
- <dt><code>machine</code></dt>
- <dd>The domain's <a
href="formatdomain.html#elementsOSBIOS">machine
- type</a>. Since not every hypervisor has a sense of machine types
- this element might be omitted in such drivers.</dd>
-
- <dt><code>arch</code></dt>
- <dd>The domain's <a
href="formatdomain.html#elementsOSBIOS">
- architecture</a>.</dd>
-
- </dl>
-
- <h3><a id="elementsCPUAllocation">CPU
Allocation</a></h3>
-
- <p>Before any devices capability occurs, there might be info on domain
- wide capabilities, e.g. virtual CPUs:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <vcpu max='255'/>
- ...
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>vcpu</code></dt>
- <dd>The maximum number of supported virtual CPUs</dd>
- </dl>
-
- <h3><a id="elementsOSBIOS">BIOS
bootloader</a></h3>
-
- <p>Sometimes users might want to tweak some BIOS knobs or use
- UEFI. For cases like that, <a
-
href="formatdomain.html#elementsOSBIOS"><code>os</code></a>
- element exposes what values can be passed to its children.</p>
-
-<pre>
-<domainCapabilities>
- ...
- <os supported='yes'>
- <enum name='firmware'>
- <value>bios</value>
- <value>efi</value>
- </enum>
- <loader supported='yes'>
- <value>/usr/share/OVMF/OVMF_CODE.fd</value>
- <enum name='type'>
- <value>rom</value>
- <value>pflash</value>
- </enum>
- <enum name='readonly'>
- <value>yes</value>
- <value>no</value>
- </enum>
- <enum name='secure'>
- <value>yes</value>
- <value>no</value>
- </enum>
- </loader>
- </os>
- ...
-<domainCapabilities>
-</pre>
-
- <p>The <code>firmware</code> enum corresponds to the
- <code>firmware</code> attribute of the <code>os</code>
element in
- the domain XML. The presence of this enum means libvirt is capable
- of the so-called firmware auto-selection feature. And the listed
- firmware values represent the accepted input in the domain
- XML. Note that the <code>firmware</code> enum reports only those
- values for which a firmware "descriptor file" exists on the host.
- Firmware descriptor file is a small JSON document that describes
- details about a given BIOS or UEFI binary on the host, e.g. the
- firmware binary path, its architecture, supported machine types,
- NVRAM template, etc. This ensures that the reported values won't
- cause a failure on guest boot.
- </p>
-
- <p>For the <code>loader</code> element, the following can
occur:</p>
-
- <dl>
- <dt><code>value</code></dt>
- <dd>List of known firmware binary paths. Currently this is used
- only to advertise the known location of OVMF binaries for
- QEMU. OVMF binaries will only be listed if they actually exist on
- host.</dd>
-
- <dt><code>type</code></dt>
- <dd>Whether the boot loader is a typical BIOS (<code>rom</code>)
- or a UEFI firmware (<code>pflash</code>). Each
<code>value</code>
- sub-element under the <code>type</code> enum represents a possible
- value for the <code>type</code> attribute for the
<loader/>
- element in the domain XML. E.g. the presence
- of <code>pfalsh</code> under the <code>type</code> enum
means that
- a domain XML can use UEFI firmware via: <loader/>
- type="pflash"
...>/path/to/the/firmware/binary/</loader>.
- </dd>
-
- <dt><code>readonly</code></dt>
- <dd>Options for the <code>readonly</code> attribute of the
- <loader/> element in the domain XML.</dd>
-
- <dt><code>secure</code></dt>
- <dd>Options for the <code>secure</code> attribute of the
- <loader/> element in the domain XML. Note that the
- value <code>yes</code> is listed only if libvirt detects a
- firmware descriptor file that has path to an OVMF binary that
- supports Secure boot, and lists its architecture and supported
- machine type.</dd>
- </dl>
-
- <h3><a id="elementsCPU">CPU configuration</a></h3>
-
- <p>
- The <code>cpu</code> element exposes options usable for configuring
- <a href="formatdomain.html#elementsCPU">guest CPUs</a>.
- </p>
-
-<pre>
-<domainCapabilities>
- ...
- <cpu>
- <mode name='host-passthrough' supported='yes'>
- <enum name='hostPassthroughMigratable'>
- <value>on</value>
- <value>off</value>
- </enum>
- </mode>
- <mode name='maximum' supported='yes'>
- <enum name='maximumMigratable'>
- <value>on</value>
- <value>off</value>
- </enum>
- </mode>
- <mode name='host-model' supported='yes'>
- <model fallback='allow'>Broadwell</model>
- <vendor>Intel</vendor>
- <feature policy='disable' name='aes'/>
- <feature policy='require' name='vmx'/>
- </mode>
- <mode name='custom' supported='yes'>
- <model usable='no'
deprecated='no'>Broadwell</model>
- <model usable='yes'
deprecated='no'>Broadwell-noTSX</model>
- <model usable='no'
deprecated='yes'>Haswell</model>
- ...
- </mode>
- </cpu>
- ...
-<domainCapabilities>
-</pre>
-
- <p>
- Each CPU mode understood by libvirt is described with a
- <code>mode</code> element which tells whether the particular mode
- is supported and provides (when applicable) more details about it:
- </p>
-
- <dl>
- <dt><code>host-passthrough</code></dt>
- <dd>
- The <code>hostPassthroughMigratable</code> enum shows possible
values
- of the <code>migratable</code> attribute for the <cpu>
element
- with <code>mode='host-passthrough'</code> in the domain XML.
- </dd>
-
- <dt><code>host-model</code></dt>
- <dd>
- If <code>host-model</code> is supported by the hypervisor, the
- <code>mode</code> describes the guest CPU which will be used when
- starting a domain with <code>host-model</code> CPU. The hypervisor
- specifics (such as unsupported CPU models or features, machine type,
- etc.) may be accounted for in this guest CPU specification and thus
- the CPU can be different from the one shown in host capabilities XML.
- This is indicated by the <code>fallback</code> attribute of the
- <code>model</code> sub element: <code>allow</code> means
not all
- specifics were accounted for and thus the CPU a guest will see may
- be different; <code>forbid</code> indicates that the CPU a guest
will
- see should match this CPU definition.
- </dd>
-
- <dt><code>custom</code></dt>
- <dd>
- The <code>mode</code> element contains a list of supported CPU
- models, each described by a dedicated <code>model</code> element.
- The <code>usable</code> attribute specifies whether the model can
- be used directly on the host. When usable='no' the corresponding model
- cannot be used without disabling some features that the CPU of such
- model is expected to have. A special value <code>unknown</code>
- indicates libvirt does not have enough information to provide the
- usability data. The <code>deprecated</code> attribute reflects
- the hypervisor's policy on usage of this model
- <span class="since">(since 7.1.0)</span>.
- </dd>
- </dl>
-
- <h3><a id="elementsIothreads">I/O Threads</a></h3>
-
- <p>
- The <code>iothread</code> elements indicates whether or not
- <a href="formatdomain.html#elementsIOThreadsAllocation">I/O
threads</a>
- are supported.
- </p>
-
-<pre>
-<domainCapabilities>
- ...
- <iothread supported='yes'/>
- ...
-<domainCapabilities>
-</pre>
-
- <h3><a id="elementsMemoryBacking">Memory
Backing</a></h3>
-
- <p>
- The <code>memory backing</code> element indicates whether or not
- <a href="formatdomain.html#memory-backing">memory
backing</a>
- is supported.
- </p>
-
-<pre>
-<domainCapabilities>
- ...
- <memoryBacking supported='yes'>
- <enum name='sourceType'>
- <value>anonymous</value>
- <value>file</value>
- <value>memfd</value>
- </enum>
- </memoryBacking>
- ...
-<domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>sourceType</code></dt>
- <dd>Options for the <code>type</code> attribute of the
- <memoryBacking><source> element.</dd>
- </dl>
-
- <h3><a id="elementsDevices">Devices</a></h3>
-
- <p>
- Another set of XML elements describe the supported devices and their
- capabilities. All devices occur as children of the main
- <code>devices</code> element.
- </p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <disk supported='yes'>
- <enum name='diskDevice'>
- <value>disk</value>
- <value>cdrom</value>
- <value>floppy</value>
- <value>lun</value>
- </enum>
- ...
- </disk>
- <hostdev supported='no'/>
- </devices>
-</domainCapabilities>
-</pre>
-
- <p>Reported capabilities are expressed as an enumerated list of available
- options for each of the element or attribute. For example, the
- <disk/> element has an attribute <code>device</code> which
can
- support the values <code>disk</code>, <code>cdrom</code>,
- <code>floppy</code>, or <code>lun</code>.</p>
-
- <h4><a id="elementsDisks">Hard drives, floppy disks,
CDROMs</a></h4>
- <p>Disk capabilities are exposed under the <code>disk</code>
element. For
- instance:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <disk supported='yes'>
- <enum name='diskDevice'>
- <value>disk</value>
- <value>cdrom</value>
- <value>floppy</value>
- <value>lun</value>
- </enum>
- <enum name='bus'>
- <value>ide</value>
- <value>fdc</value>
- <value>scsi</value>
- <value>virtio</value>
- <value>xen</value>
- <value>usb</value>
- <value>sata</value>
- <value>sd</value>
- </enum>
- </disk>
- ...
- </devices>
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>diskDevice</code></dt>
- <dd>Options for the <code>device</code> attribute of the
<disk/>
- element.</dd>
-
- <dt><code>bus</code></dt>
- <dd>Options for the <code>bus</code> attribute of the
<target/>
- element for a <disk/>.</dd>
- </dl>
-
-
- <h4><a id="elementsGraphics">Graphical
framebuffers</a></h4>
- <p>Graphics device capabilities are exposed under the
- <code>graphics</code> element. For instance:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <graphics supported='yes'>
- <enum name='type'>
- <value>sdl</value>
- <value>vnc</value>
- <value>spice</value>
- </enum>
- </graphics>
- ...
- </devices>
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>type</code></dt>
- <dd>Options for the <code>type</code> attribute of the
<graphics/>
- element.</dd>
- </dl>
-
-
- <h4><a id="elementsVideo">Video device</a></h4>
- <p>Video device capabilities are exposed under the
- <code>video</code> element. For instance:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <video supported='yes'>
- <enum name='modelType'>
- <value>vga</value>
- <value>cirrus</value>
- <value>vmvga</value>
- <value>qxl</value>
- <value>virtio</value>
- </enum>
- </video>
- ...
- </devices>
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>modelType</code></dt>
- <dd>Options for the <code>type</code> attribute of the
- <video><model> element.</dd>
- </dl>
-
-
- <h4><a id="elementsHostDev">Host device
assignment</a></h4>
- <p>Some host devices can be passed through to a guest (e.g. USB, PCI and
- SCSI). Well, only if the following is enabled:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <hostdev supported='yes'>
- <enum name='mode'>
- <value>subsystem</value>
- <value>capabilities</value>
- </enum>
- <enum name='startupPolicy'>
- <value>default</value>
- <value>mandatory</value>
- <value>requisite</value>
- <value>optional</value>
- </enum>
- <enum name='subsysType'>
- <value>usb</value>
- <value>pci</value>
- <value>scsi</value>
- </enum>
- <enum name='capsType'>
- <value>storage</value>
- <value>misc</value>
- <value>net</value>
- </enum>
- <enum name='pciBackend'>
- <value>default</value>
- <value>kvm</value>
- <value>vfio</value>
- <value>xen</value>
- </enum>
- </hostdev>
- </devices>
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>mode</code></dt>
- <dd>Options for the <code>mode</code> attribute of the
<hostdev/>
- element.</dd>
-
- <dt><code>startupPolicy</code></dt>
- <dd>Options for the <code>startupPolicy</code> attribute of the
- <hostdev/> element.</dd>
-
- <dt><code>subsysType</code></dt>
- <dd>Options for the <code>type</code> attribute of the
<hostdev/>
- element in case of <code>mode="subsystem"</code>.</dd>
-
- <dt><code>capsType</code></dt>
- <dd>Options for the <code>type</code> attribute of the
<hostdev/>
- element in case of
<code>mode="capabilities"</code>.</dd>
-
- <dt><code>pciBackend</code></dt>
- <dd>Options for the <code>name</code> attribute of the
<driver/>
- element.</dd>
- </dl>
-
-
- <h4><a id="elementsRNG">RNG device</a></h4>
- <p>RNG device capabilities are exposed under the
- <code>rng</code> element. For instance:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <rng supported='yes'>
- <enum name='model'>
- <value>virtio</value>
- <value>virtio-transitional</value>
- <value>virtio-non-transitional</value>
- </enum>
- <enum name='backendModel'>
- <value>random</value>
- <value>egd</value>
- <value>builtin</value>
- </enum>
- </rng>
- ...
- </devices>
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>model</code></dt>
- <dd>Options for the <code>model</code> attribute of the
- <rng> element.</dd>
- <dt><code>backendModel</code></dt>
- <dd>Options for the <code>model</code> attribute of the
- <rng><backend> element.</dd>
- </dl>
-
-
- <h4><a id="elementsFilesystem">Filesystem
device</a></h4>
- <p>Filesystem device capabilities are exposed under the
- <code>filesystem</code> element. For instance:</p>
-
-<pre>
-<domainCapabilities>
- ...
- <devices>
- <filesystem supported='yes'>
- <enum name='driverType'>
- <value>default</value>
- <value>path</value>
- <value>handle</value>
- <value>virtiofs</value>
- </enum>
- </filesystem>
- ...
- </devices>
-</domainCapabilities>
-</pre>
-
- <dl>
- <dt><code>driverType</code></dt>
- <dd>Options for the <code>type</code> attribute of the
- <filesystem><driver> element.</dd>
- </dl>
-
-
- <h3><a id="elementsFeatures">Features</a></h3>
-
- <p>One more set of XML elements describe the supported features and
- their capabilities. All features occur as children of the main
- <code>features</code> element.</p>
-
-<pre>
-<domainCapabilities>
- ...
- <features>
- <gic supported='yes'>
- <enum name='version'>
- <value>2</value>
- <value>3</value>
- </enum>
- </gic>
- <vmcoreinfo supported='yes'/>
- <genid supported='yes'/>
- <backingStoreInput supported='yes'/>
- <backup supported='yes'/>
- <sev>
- <cbitpos>47</cbitpos>
- <reduced-phys-bits>1</reduced-phys-bits>
- </sev>
- </features>
-</domainCapabilities>
-</pre>
-
- <p>Reported capabilities are expressed as an enumerated list of
- possible values for each of the elements or attributes. For example, the
- <code>gic</code> element has an attribute
<code>version</code> which can
- support the values <code>2</code> or
<code>3</code>.</p>
-
- <p>For information about the purpose of each feature, see the
- <a href="formatdomain.html#elementsFeatures">relevant
section</a> in
- the domain XML documentation.
- </p>
-
- <h4><a id="elementsGIC">GIC capabilities</a></h4>
-
- <p>GIC capabilities are exposed under the <code>gic</code>
element.</p>
-
- <dl>
- <dt><code>version</code></dt>
- <dd>Options for the <code>version</code> attribute of the
- <code>gic</code> element.</dd>
- </dl>
-
- <h4><a id="elementsvmcoreinfo">vmcoreinfo</a></h4>
-
- <p>Reports whether the vmcoreinfo feature can be enabled.</p>
-
- <h4><a id="elementsgenid">genid</a></h4>
-
- <p>Reports whether the genid feature can be used by the domain.</p>
-
- <h4><a
id="featureBackingStoreInput">backingStoreInput</a></h4>
-
- <p>Reports whether the hypervisor will obey the <backingStore>
- elements configured for a <disk> when booting the guest, hotplugging
- the disk to a running guest, or similar.
- <span class="since">(Since 5.10)</span>
- </p>
-
- <h4><a id="featureBackup">backup</a></h4>
-
- <p>Reports whether the hypervisor supports the backup, checkpoint, and
- related features. (<code>virDomainBackupBegin</code>,
- <code>virDomainCheckpointCreateXML</code> etc). The presence of the
- <code>backup</code> element even if
<code>supported='no'</code> implies that
- the <code>VIR_DOMAIN_UNDEFINE_CHECKPOINTS_METADATA</code> flag for
- <code>virDomainUndefine</code> is supported.
- </p>
-
- <h4><a id="elementsS390PV">s390-pv
capability</a></h4>
-
- <p>Reports whether the hypervisor supports the Protected Virtualization.
- In order to use Protected Virtualization with libvirt have a look at the
- <a href="formatdomain.html#launchSecurity">launchSecurity element in
the
- domain XML</a>. For more details on the Protected Virtualization feature
- please see <a href="kbase/s390_protected_virt.html">Protected
- Virtualization on s390</a>.
- </p>
-
- <h4><a id="elementsSEV">SEV capabilities</a></h4>
-
- <p>AMD Secure Encrypted Virtualization (SEV) capabilities are exposed under
- the <code>sev</code> element.
- SEV is an extension to the AMD-V architecture which supports running
- virtual machines (VMs) under the control of a hypervisor. When supported,
- guest owner can create a VM whose memory contents will be transparently
- encrypted with a key unique to that VM.</p>
-
- <p>
- For more details on the SEV feature, please follow resources in the
- AMD developer's document store. In order to use SEV with libvirt have
- a look at <a href="formatdomain.html#launchSecurity">SEV in domain
XML</a>
- </p>
-
- <dl>
- <dt><code>cbitpos</code></dt>
- <dd>When memory encryption is enabled, one of the physical address bits
- (aka the C-bit) is utilized to mark if a memory page is protected. The
- C-bit position is Hypervisor dependent.</dd>
- <dt><code>reducedPhysBits</code></dt>
- <dd>When memory encryption is enabled, we lose certain bits in physical
- address space. The number of bits we lose is hypervisor dependent.</dd>
- <dt><code>maxGuests</code></dt>
- <dd>The maximum number of SEV guests that can be launched on the host.
- This value may be configurable in the firmware for some hosts.</dd>
- <dt><code>maxESGuests</code></dt>
- <dd>The maximum number of SEV-ES guests that can be launched on the host.
- This value may be configurable in the firmware for some hosts.</dd>
- </dl>
-
- </body>
-</html>
diff --git a/docs/formatdomaincaps.rst b/docs/formatdomaincaps.rst
new file mode 100644
index 0000000000..c07c07da4b
--- /dev/null
+++ b/docs/formatdomaincaps.rst
@@ -0,0 +1,602 @@
+.. role:: since
+
+==============================
+Domain capabilities XML format
+==============================
+
+.. contents::
+
+Overview
+--------
+
+Sometimes, when a new domain is to be created it may come handy to know the
+capabilities of the hypervisor so the correct combination of devices and drivers
+is used. For example, when management application is considering the mode for a
+host device's passthrough there are several options depending not only on host,
+but on hypervisor in question too. If the hypervisor is qemu then it needs to be
+more recent to support VFIO, while legacy KVM is achievable just fine with older
+qemus.
+
+The main difference between
+`virConnectGetCapabilities
</html/libvirt-libvirt-host.html#virConnectGetCapabilities>`__
+and the emulator capabilities API is, the former one aims more on the host
+capabilities (e.g. NUMA topology, security models in effect, etc.) while the
+latter one specializes on the hypervisor capabilities.
+
+While the `Driver Capabilities <formatcaps.html>`__ provides the host
+capabilities (e.g NUMA topology, security models in effect, etc.), the Domain
+Capabilities provides the hypervisor specific capabilities for Management
+Applications to query and make decisions regarding what to utilize.
+
+The Domain Capabilities can provide information such as the correct combination
+of devices and drivers that are supported. Knowing which host and hypervisor
+specific options are available or supported would allow the management
+application to choose an appropriate mode for a pass-through host device as well
+as which adapter to utilize.
+
+Some XML elements may be entirely omitted from the domaincapabilities XML,
+depending on what the libvirt driver has filled in. Applications should only act
+on what is explicitly reported in the domaincapabilities XML. For example, if
+<disk supported='yes'/> is present, you can safely assume the driver
supports
+<disk> devices. If <disk supported='no'/> is present, you can safely
assume the
+driver does NOT support <disk> devices. If the <disk> block is omitted
entirely,
+the driver is not indicating one way or the other whether it supports <disk>
+devices, and applications should not interpret the missing block to mean any
+thing in particular.
+
+Element and attribute overview
+------------------------------
+
+A new query interface was added to the virConnect API's to retrieve the XML
+listing of the set of domain capabilities ( :since:`Since 1.2.7` ):
+
+::
+
+ virConnectGetDomainCapabilities
+
+The root element that emulator capability XML document starts with has name
+``domainCapabilities``. It contains at least four direct child elements:
+
+::
+
+ <domainCapabilities>
+ <path>/usr/bin/qemu-system-x86_64</path>
+ <domain>kvm</domain>
+ <machine>pc-i440fx-2.1</machine>
+ <arch>x86_64</arch>
+ ...
+ </domainCapabilities>
+
+``path``
+ The full path to the emulator binary.
+``domain``
+ Describes the `virtualization type <formatdomain.html#elements>`__ (or so
+ called domain type).
+``machine``
+ The domain's `machine type <formatdomain.html#elementsOSBIOS>`__. Since not
+ every hypervisor has a sense of machine types this element might be omitted
+ in such drivers.
+``arch``
+ The domain's `architecture <formatdomain.html#elementsOSBIOS>`__.
+
+CPU Allocation
+~~~~~~~~~~~~~~
+
+Before any devices capability occurs, there might be info on domain wide
+capabilities, e.g. virtual CPUs:
+
+::
+
+ <domainCapabilities>
+ ...
+ <vcpu max='255'/>
+ ...
+ </domainCapabilities>
+
+``vcpu``
+ The maximum number of supported virtual CPUs
+
+BIOS bootloader
+~~~~~~~~~~~~~~~
+
+Sometimes users might want to tweak some BIOS knobs or use UEFI. For cases like
+that, `os <formatdomain.html#elementsOSBIOS>`__ element exposes what values can
+be passed to its children.
+
+::
+
+ <domainCapabilities>
+ ...
+ <os supported='yes'>
+ <enum name='firmware'>
+ <value>bios</value>
+ <value>efi</value>
+ </enum>
+ <loader supported='yes'>
+ <value>/usr/share/OVMF/OVMF_CODE.fd</value>
+ <enum name='type'>
+ <value>rom</value>
+ <value>pflash</value>
+ </enum>
+ <enum name='readonly'>
+ <value>yes</value>
+ <value>no</value>
+ </enum>
+ <enum name='secure'>
+ <value>yes</value>
+ <value>no</value>
+ </enum>
+ </loader>
+ </os>
+ ...
+ <domainCapabilities>
+
+The ``firmware`` enum corresponds to the ``firmware`` attribute of the ``os``
+element in the domain XML. The presence of this enum means libvirt is capable of
+the so-called firmware auto-selection feature. And the listed firmware values
+represent the accepted input in the domain XML. Note that the ``firmware`` enum
+reports only those values for which a firmware "descriptor file" exists on the
+host. Firmware descriptor file is a small JSON document that describes details
+about a given BIOS or UEFI binary on the host, e.g. the firmware binary path,
+its architecture, supported machine types, NVRAM template, etc. This ensures
+that the reported values won't cause a failure on guest boot.
+
+For the ``loader`` element, the following can occur:
+
+``value``
+ List of known firmware binary paths. Currently this is used only to advertise
+ the known location of OVMF binaries for QEMU. OVMF binaries will only be
+ listed if they actually exist on host.
+``type``
+ Whether the boot loader is a typical BIOS (``rom``) or a UEFI firmware
+ (``pflash``). Each ``value`` sub-element under the ``type`` enum represents a
+ possible value for the ``type`` attribute for the <loader/> element in the
+ domain XML. E.g. the presence of ``pfalsh`` under the ``type`` enum means
+ that a domain XML can use UEFI firmware via: <loader/> type="pflash"
+ ...>/path/to/the/firmware/binary/</loader>.
+``readonly``
+ Options for the ``readonly`` attribute of the <loader/> element in the domain
+ XML.
+``secure``
+ Options for the ``secure`` attribute of the <loader/> element in the domain
+ XML. Note that the value ``yes`` is listed only if libvirt detects a firmware
+ descriptor file that has path to an OVMF binary that supports Secure boot,
+ and lists its architecture and supported machine type.
+
+CPU configuration
+~~~~~~~~~~~~~~~~~
+
+The ``cpu`` element exposes options usable for configuring `guest
+CPUs <formatdomain.html#elementsCPU>`__.
+
+::
+
+ <domainCapabilities>
+ ...
+ <cpu>
+ <mode name='host-passthrough' supported='yes'>
+ <enum name='hostPassthroughMigratable'>
+ <value>on</value>
+ <value>off</value>
+ </enum>
+ </mode>
+ <mode name='maximum' supported='yes'>
+ <enum name='maximumMigratable'>
+ <value>on</value>
+ <value>off</value>
+ </enum>
+ </mode>
+ <mode name='host-model' supported='yes'>
+ <model fallback='allow'>Broadwell</model>
+ <vendor>Intel</vendor>
+ <feature policy='disable' name='aes'/>
+ <feature policy='require' name='vmx'/>
+ </mode>
+ <mode name='custom' supported='yes'>
+ <model usable='no'
deprecated='no'>Broadwell</model>
+ <model usable='yes'
deprecated='no'>Broadwell-noTSX</model>
+ <model usable='no' deprecated='yes'>Haswell</model>
+ ...
+ </mode>
+ </cpu>
+ ...
+ <domainCapabilities>
+
+Each CPU mode understood by libvirt is described with a ``mode`` element which
+tells whether the particular mode is supported and provides (when applicable)
+more details about it:
+
+``host-passthrough``
+ The ``hostPassthroughMigratable`` enum shows possible values of the
+ ``migratable`` attribute for the <cpu> element with
+ ``mode='host-passthrough'`` in the domain XML.
+``host-model``
+ If ``host-model`` is supported by the hypervisor, the ``mode`` describes the
+ guest CPU which will be used when starting a domain with ``host-model`` CPU.
+ The hypervisor specifics (such as unsupported CPU models or features, machine
+ type, etc.) may be accounted for in this guest CPU specification and thus the
+ CPU can be different from the one shown in host capabilities XML. This is
+ indicated by the ``fallback`` attribute of the ``model`` sub element:
+ ``allow`` means not all specifics were accounted for and thus the CPU a guest
+ will see may be different; ``forbid`` indicates that the CPU a guest will see
+ should match this CPU definition.
+``custom``
+ The ``mode`` element contains a list of supported CPU models, each described
+ by a dedicated ``model`` element. The ``usable`` attribute specifies whether
+ the model can be used directly on the host. When usable='no' the
+ corresponding model cannot be used without disabling some features that the
+ CPU of such model is expected to have. A special value ``unknown`` indicates
+ libvirt does not have enough information to provide the usability data. The
+ ``deprecated`` attribute reflects the hypervisor's policy on usage of this
+ model :since:`(since 7.1.0)` .
+
+I/O Threads
+~~~~~~~~~~~
+
+The ``iothread`` elements indicates whether or not `I/O
+threads <formatdomain.html#elementsIOThreadsAllocation>`__ are supported.
+
+::
+
+ <domainCapabilities>
+ ...
+ <iothread supported='yes'/>
+ ...
+ <domainCapabilities>
+
+Memory Backing
+~~~~~~~~~~~~~~
+
+The ``memory backing`` element indicates whether or not `memory
+backing <formatdomain.html#memory-backing>`__ is supported.
+
+::
+
+ <domainCapabilities>
+ ...
+ <memoryBacking supported='yes'>
+ <enum name='sourceType'>
+ <value>anonymous</value>
+ <value>file</value>
+ <value>memfd</value>
+ </enum>
+ </memoryBacking>
+ ...
+ <domainCapabilities>
+
+``sourceType``
+ Options for the ``type`` attribute of the <memoryBacking><source>
element.
+
+Devices
+~~~~~~~
+
+Another set of XML elements describe the supported devices and their
+capabilities. All devices occur as children of the main ``devices`` element.
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <disk supported='yes'>
+ <enum name='diskDevice'>
+ <value>disk</value>
+ <value>cdrom</value>
+ <value>floppy</value>
+ <value>lun</value>
+ </enum>
+ ...
+ </disk>
+ <hostdev supported='no'/>
+ </devices>
+ </domainCapabilities>
+
+Reported capabilities are expressed as an enumerated list of available options
+for each of the element or attribute. For example, the <disk/> element has an
+attribute ``device`` which can support the values ``disk``, ``cdrom``,
+``floppy``, or ``lun``.
+
+Hard drives, floppy disks, CDROMs
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Disk capabilities are exposed under the ``disk`` element. For instance:
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <disk supported='yes'>
+ <enum name='diskDevice'>
+ <value>disk</value>
+ <value>cdrom</value>
+ <value>floppy</value>
+ <value>lun</value>
+ </enum>
+ <enum name='bus'>
+ <value>ide</value>
+ <value>fdc</value>
+ <value>scsi</value>
+ <value>virtio</value>
+ <value>xen</value>
+ <value>usb</value>
+ <value>sata</value>
+ <value>sd</value>
+ </enum>
+ </disk>
+ ...
+ </devices>
+ </domainCapabilities>
+
+``diskDevice``
+ Options for the ``device`` attribute of the <disk/> element.
+``bus``
+ Options for the ``bus`` attribute of the <target/> element for a <disk/>.
+
+Graphical framebuffers
+^^^^^^^^^^^^^^^^^^^^^^
+
+Graphics device capabilities are exposed under the ``graphics`` element. For
+instance:
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <graphics supported='yes'>
+ <enum name='type'>
+ <value>sdl</value>
+ <value>vnc</value>
+ <value>spice</value>
+ </enum>
+ </graphics>
+ ...
+ </devices>
+ </domainCapabilities>
+
+``type``
+ Options for the ``type`` attribute of the <graphics/> element.
+
+Video device
+^^^^^^^^^^^^
+
+Video device capabilities are exposed under the ``video`` element. For instance:
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <video supported='yes'>
+ <enum name='modelType'>
+ <value>vga</value>
+ <value>cirrus</value>
+ <value>vmvga</value>
+ <value>qxl</value>
+ <value>virtio</value>
+ </enum>
+ </video>
+ ...
+ </devices>
+ </domainCapabilities>
+
+``modelType``
+ Options for the ``type`` attribute of the <video><model> element.
+
+Host device assignment
+^^^^^^^^^^^^^^^^^^^^^^
+
+Some host devices can be passed through to a guest (e.g. USB, PCI and SCSI).
+Well, only if the following is enabled:
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <hostdev supported='yes'>
+ <enum name='mode'>
+ <value>subsystem</value>
+ <value>capabilities</value>
+ </enum>
+ <enum name='startupPolicy'>
+ <value>default</value>
+ <value>mandatory</value>
+ <value>requisite</value>
+ <value>optional</value>
+ </enum>
+ <enum name='subsysType'>
+ <value>usb</value>
+ <value>pci</value>
+ <value>scsi</value>
+ </enum>
+ <enum name='capsType'>
+ <value>storage</value>
+ <value>misc</value>
+ <value>net</value>
+ </enum>
+ <enum name='pciBackend'>
+ <value>default</value>
+ <value>kvm</value>
+ <value>vfio</value>
+ <value>xen</value>
+ </enum>
+ </hostdev>
+ </devices>
+ </domainCapabilities>
+
+``mode``
+ Options for the ``mode`` attribute of the <hostdev/> element.
+``startupPolicy``
+ Options for the ``startupPolicy`` attribute of the <hostdev/> element.
+``subsysType``
+ Options for the ``type`` attribute of the <hostdev/> element in case of
+ ``mode="subsystem"``.
+``capsType``
+ Options for the ``type`` attribute of the <hostdev/> element in case of
+ ``mode="capabilities"``.
+``pciBackend``
+ Options for the ``name`` attribute of the <driver/> element.
+
+RNG device
+^^^^^^^^^^
+
+RNG device capabilities are exposed under the ``rng`` element. For instance:
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <rng supported='yes'>
+ <enum name='model'>
+ <value>virtio</value>
+ <value>virtio-transitional</value>
+ <value>virtio-non-transitional</value>
+ </enum>
+ <enum name='backendModel'>
+ <value>random</value>
+ <value>egd</value>
+ <value>builtin</value>
+ </enum>
+ </rng>
+ ...
+ </devices>
+ </domainCapabilities>
+
+``model``
+ Options for the ``model`` attribute of the <rng> element.
+``backendModel``
+ Options for the ``model`` attribute of the <rng><backend> element.
+
+Filesystem device
+^^^^^^^^^^^^^^^^^
+
+Filesystem device capabilities are exposed under the ``filesystem`` element. For
+instance:
+
+::
+
+ <domainCapabilities>
+ ...
+ <devices>
+ <filesystem supported='yes'>
+ <enum name='driverType'>
+ <value>default</value>
+ <value>path</value>
+ <value>handle</value>
+ <value>virtiofs</value>
+ </enum>
+ </filesystem>
+ ...
+ </devices>
+ </domainCapabilities>
+
+``driverType``
+ Options for the ``type`` attribute of the <filesystem><driver> element.
+
+Features
+~~~~~~~~
+
+One more set of XML elements describe the supported features and their
+capabilities. All features occur as children of the main ``features`` element.
+
+::
+
+ <domainCapabilities>
+ ...
+ <features>
+ <gic supported='yes'>
+ <enum name='version'>
+ <value>2</value>
+ <value>3</value>
+ </enum>
+ </gic>
+ <vmcoreinfo supported='yes'/>
+ <genid supported='yes'/>
+ <backingStoreInput supported='yes'/>
+ <backup supported='yes'/>
+ <sev>
+ <cbitpos>47</cbitpos>
+ <reduced-phys-bits>1</reduced-phys-bits>
+ </sev>
+ </features>
+ </domainCapabilities>
+
+Reported capabilities are expressed as an enumerated list of possible values for
+each of the elements or attributes. For example, the ``gic`` element has an
+attribute ``version`` which can support the values ``2`` or ``3``.
+
+For information about the purpose of each feature, see the `relevant
+section <formatdomain.html#elementsFeatures>`__ in the domain XML documentation.
+
+GIC capabilities
+^^^^^^^^^^^^^^^^
+
+GIC capabilities are exposed under the ``gic`` element.
+
+``version``
+ Options for the ``version`` attribute of the ``gic`` element.
+
+vmcoreinfo
+^^^^^^^^^^
+
+Reports whether the vmcoreinfo feature can be enabled.
+
+genid
+^^^^^
+
+Reports whether the genid feature can be used by the domain.
+
+backingStoreInput
+^^^^^^^^^^^^^^^^^
+
+Reports whether the hypervisor will obey the <backingStore> elements configured
+for a <disk> when booting the guest, hotplugging the disk to a running guest, or
+similar. :since:`(Since 5.10)`
+
+backup
+^^^^^^
+
+Reports whether the hypervisor supports the backup, checkpoint, and related
+features. (``virDomainBackupBegin``, ``virDomainCheckpointCreateXML`` etc). The
+presence of the ``backup`` element even if ``supported='no'`` implies that the
+``VIR_DOMAIN_UNDEFINE_CHECKPOINTS_METADATA`` flag for ``virDomainUndefine`` is
+supported.
+
+s390-pv capability
+^^^^^^^^^^^^^^^^^^
+
+Reports whether the hypervisor supports the Protected Virtualization. In order
+to use Protected Virtualization with libvirt have a look at the `launchSecurity
+element in the domain XML <formatdomain.html#launchSecurity>`__. For more
+details on the Protected Virtualization feature please see `Protected
+Virtualization on s390 <kbase/s390_protected_virt.html>`__.
+
+SEV capabilities
+^^^^^^^^^^^^^^^^
+
+AMD Secure Encrypted Virtualization (SEV) capabilities are exposed under the
+``sev`` element. SEV is an extension to the AMD-V architecture which supports
+running virtual machines (VMs) under the control of a hypervisor. When
+supported, guest owner can create a VM whose memory contents will be
+transparently encrypted with a key unique to that VM.
+
+For more details on the SEV feature, please follow resources in the AMD
+developer's document store. In order to use SEV with libvirt have a look at `SEV
+in domain XML <formatdomain.html#launchSecurity>`__
+
+``cbitpos``
+ When memory encryption is enabled, one of the physical address bits (aka the
+ C-bit) is utilized to mark if a memory page is protected. The C-bit position
+ is Hypervisor dependent.
+``reducedPhysBits``
+ When memory encryption is enabled, we lose certain bits in physical address
+ space. The number of bits we lose is hypervisor dependent.
+``maxGuests``
+ The maximum number of SEV guests that can be launched on the host. This value
+ may be configurable in the firmware for some hosts.
+``maxESGuests``
+ The maximum number of SEV-ES guests that can be launched on the host. This
+ value may be configurable in the firmware for some hosts.
diff --git a/docs/kbase/backing_chains.rst b/docs/kbase/backing_chains.rst
index 89920a61b1..38a9a2337b 100644
--- a/docs/kbase/backing_chains.rst
+++ b/docs/kbase/backing_chains.rst
@@ -97,7 +97,7 @@ specification can be used:
</disk>
This makes libvirt follow the settings as configured in the XML. Note that this
-is supported only when the
https://libvirt.org/formatdomaincaps.html#featureBackingStoreInput
+is supported only when the https://libvirt.org/formatdomaincaps.html#backingstoreinput
capability is present.
An empty ``<backingStore/>`` element signals the end of the chain. Using this
diff --git a/docs/meson.build b/docs/meson.build
index 95c9babcf5..81f348398d 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -22,7 +22,6 @@ docs_html_in_files = [
'csharp',
'dbus',
'docs',
- 'formatdomaincaps',
'formatnetwork',
'formatnetworkport',
'formatnode',
@@ -85,6 +84,7 @@ docs_rst_files = [
'formatcaps',
'formatcheckpoint',
'formatdomain',
+ 'formatdomaincaps',
'formatsecret',
'formatsnapshot',
'formatstorage',
--
2.35.1