<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <!-- This file is autogenerated from formatcaps.html.in Do not edit this file. Changes will be lost. --> <!-- This page was generated at Mon Nov 13 21:46:26 UTC 2017. --> <head> <meta charset="UTF-8"/> <meta name="viewport" content="width=device-width, initial-scale=1"/> <link rel="stylesheet" type="text/css" href="main.css"/> <link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png"/> <link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png"/> <link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png"/> <link rel="manifest" href="/manifest.json"/> <meta name="theme-color" content="#ffffff"/> <title>libvirt: Driver capabilities XML format</title> <meta name="description" content="libvirt, virtualization, virtualization API"/> <script type="text/javascript"> <!-- function init() { window.addEventListener('scroll', function(e){ var distanceY = window.pageYOffset || document.documentElement.scrollTop, shrinkOn = 94 home = document.getElementById("home"); links = document.getElementById("jumplinks"); search = document.getElementById("search"); body = document.getElementById("body"); if (distanceY > shrinkOn) { if (home.className != "navhide") { body.className = "navhide" home.className = "navhide" links.className = "navhide" search.className = "navhide" } } else { if (home.className == "navhide") { body.className = "" home.className = "" links.className = "" search.className = "" } } }); } window.onload = init(); --> </script> </head> <body> <div id="body"> <div id="content"> <h1>Driver capabilities XML format</h1> <ul> <li> <a href="#elements">Element and attribute overview</a> <ul> <li> <a href="#elementHost">Host capabilities</a> </li> <li> <a href="#elementGuest">Guest capabilities</a> </li> <li> <a href="#elementExamples">Examples</a> </li> </ul> </li> </ul> <h2> <a id="elements">Element and attribute overview</a> <a class="headerlink" href="#elements" title="Permalink to this headline">¶</a> </h2> <p>As new virtualization engine support gets added to libvirt, and to handle cases like QEMU supporting a variety of emulations, a query interface has been added in 0.2.1 allowing to list the set of supported virtualization capabilities on the host:</p> <pre>char * virConnectGetCapabilities (virConnectPtr conn);</pre> <p>The value returned is an XML document listing the virtualization capabilities of the host and virtualization engine to which <code>@conn</code> is connected. One can test it using <code>virsh</code> command line tool command '<code>capabilities</code>', it dumps the XML associated to the current connection. </p> <p>As can be seen in the <a href="#elementExamples">example</a>, the capabilities XML consists of the <code>capabilities</code> element which have exactly one <code>host</code> child element to report information on host capabilities, and zero or more <code>guest</code> element to express the set of architectures the host can run at the moment.</p> <h3> <a id="elementHost">Host capabilities</a> <a class="headerlink" href="#elementHost" title="Permalink to this headline">¶</a> </h3> <p>The <code><host/></code> element consists of the following child elements:</p> <dl> <dt> <code>uuid</code> </dt> <dd>The host UUID.</dd> <dt> <code>cpu</code> </dt> <dd>The host CPU architecture and features.</dd> <dt> <code>power_management</code> </dt> <dd>whether host is capable of memory suspend, disk hibernation, or hybrid suspend.</dd> <dt> <code>migration</code> </dt> <dd>This element exposes information on the hypervisor's migration capabilities, like live migration, supported URI transports, and so on.</dd> <dt> <code>topology</code> </dt> <dd>This element embodies the host internal topology. Management applications may want to learn this information when orchestrating new guests - e.g. due to reduce inter-NUMA node transfers.</dd> <dt> <code>secmodel</code> </dt> <dd>To find out default security labels for different security models you need to parse this element. In contrast with the former elements, this is repeated for each security model the libvirt daemon currently supports. </dd> </dl> <h3> <a id="elementGuest">Guest capabilities</a> <a class="headerlink" href="#elementGuest" title="Permalink to this headline">¶</a> </h3> <p>While the <a href="#elementHost">previous section</a> aims at host capabilities, this one focuses on capabilities available to a guest using a given hypervisor. The <code><guest/></code> element will typically wrap up the following elements:</p> <dl> <dt> <code>os_type</code> </dt> <dd>This expresses what kind of operating system the hypervisor is able to run. Possible values are: <dl><dt><code>xen</code></dt><dd>for XEN</dd><dt><code>linux</code></dt><dd>legacy alias for <code>xen</code></dd><dt><code>hvm</code></dt><dd>Unmodified operating system</dd><dt><code>exe</code></dt><dd>Container based virtualization</dd><dt><code>uml</code></dt><dd>User Mode Linux</dd></dl> </dd> <dt> <code>arch</code> </dt> <dd>This element brings some information on supported guest architecture.</dd> <dt> <code>features</code> </dt> <dd>This optional element encases possible features that can be used with a guest of described type. Possible subelements are: <dl><dt><code>pae</code></dt><dd>If present, 32-bit guests can use PAE address space extensions, <span class="since">since 0.4.1</span></dd><dt><code>nonpae</code></dt><dd>If present, 32-bit guests can be run without requiring PAE, <span class="since">since 0.4.1</span></dd><dt><code>ia64_be</code></dt><dd>If present, IA64 guests can be run in big-endian mode, <span class="since">since 0.4.1</span></dd><dt><code>acpi</code></dt><dd>If this element is present, the <code>default</code> attribute describes whether the hypervisor exposes ACPI to the guest by default, and the <code>toggle</code> attribute describes whether the user can override this default. <span class="since">Since 0.4.1</span></dd><dt><code>apic</code></dt><dd>If this element is present, the <code>default</code> attribute describes whether the hypervisor exposes APIC to the guest by default, and the <code>toggle</code> attribute describes whether the user can override this default. <span class="since">Since 0.4.1</span></dd><dt><code>cpuselection</code></dt><dd>If this element is present, the hypervisor supports the <code><cpu></code> element within a domain definition for fine-grained control over the CPU presented to the guest. <span class="since">Since 0.7.5</span></dd><dt><code>deviceboot</code></dt><dd>If this element is present, the <code><boot order='...'/></code> element can be used inside devices, rather than the older boot specification by category. <span class="since">Since 0.8.8</span></dd><dt><code>disksnapshot</code></dt><dd>If this element is present, the <code>default</code> attribute describes whether external disk snapshots are supported. If absent, external snapshots may still be supported, but it requires attempting the API and checking for an error to find out for sure. <span class="since">Since 1.2.3</span></dd></dl> </dd> </dl> <h3> <a id="elementExamples">Examples</a> <a class="headerlink" href="#elementExamples" title="Permalink to this headline">¶</a> </h3> <p>For example, in the case of a 64-bit machine with hardware virtualization capabilities enabled in the chip and BIOS you will see:</p> <pre><capabilities> <span style="color: #E50000"><host> <cpu> <arch>x86_64</arch> <features> <vmx/> </features> <model>core2duo</model> <vendor>Intel</vendor> <topology sockets="1" cores="2" threads="1"/> <feature name="lahf_lm"/> <feature name='xtpr'/> ... </cpu> <power_management> <suspend_mem/> <suspend_disk/> <suspend_hybrid/> </power_management> </host></span> <!-- xen-3.0-x86_64 --> <span style="color: #0000E5"><guest> <os_type>xen</os_type> <arch name="x86_64"> <wordsize>64</wordsize> <domain type="xen"></domain> <emulator>/usr/lib64/xen/bin/qemu-dm</emulator> </arch> <features> </features> </guest></span> <!-- hvm-3.0-x86_32 --> <span style="color: #00B200"><guest> <os_type>hvm</os_type> <arch name="i686"> <wordsize>32</wordsize> <domain type="xen"></domain> <emulator>/usr/lib/xen/bin/qemu-dm</emulator> <machine>pc</machine> <machine>isapc</machine> <loader>/usr/lib/xen/boot/hvmloader</loader> </arch> <features> <cpuselection/> <deviceboot/> </features> </guest></span> ... </capabilities></pre> </div> </div> <div id="nav"> <div id="home"> <a href="index.html">Home</a> </div> <div id="jumplinks"> <ul> <li> <a href="downloads.html">Download</a> </li> <li> <a href="contribute.html">Contribute</a> </li> <li> <a href="docs.html">Docs</a> </li> </ul> </div> <div id="search"> <form action="search.php" enctype="application/x-www-form-urlencoded" method="get"> <div> <input name="query" type="text" size="12" value=""/> <input name="submit" type="submit" value="Go"/> </div> </form> </div> </div> <div id="footer"> <div id="contact"> <h3>Contact</h3> <ul> <li> <a href="contact.html#email">email</a> </li> <li> <a href="contact.html#irc">irc</a> </li> </ul> </div> <div id="community"> <h3>Community</h3> <ul> <li> <a href="https://twitter.com/hashtag/libvirt">twitter</a> </li> <li> <a href="https://plus.google.com/communities/109522598353007505282">google+</a> </li> <li> <a href="http://stackoverflow.com/questions/tagged/libvirt">stackoverflow</a> </li> <li> <a href="http://serverfault.com/questions/tagged/libvirt">serverfault</a> </li> </ul> </div> <div id="conduct"> Participants in the libvirt project agree to abide by <a href="governance.html#codeofconduct">the project code of conduct</a></div> <br class="clear"/> </div> </body> </html>