[libvirt] [PATCH] docs: document <address> elements in one place
Eric Blake
eblake at redhat.com
Fri Dec 9 23:35:33 UTC 2011
Improve the documentation of what forms a valid <address> element,
since these elements appear in numerous devices.
* docs/formatdomain.html.in (elementsAddress): New section.
(elementsControllers, elementsUSB, elementsNICS, elementsInput)
(elementsHub, elementsCharChannel, elementsSound): Refer to it.
---
I went ahead and assumed Michael's SPAPR-VIO patches go in, but
I was guessing on the content to use there.
docs/formatdomain.html.in | 133 +++++++++++++++++++++++++++++++++------------
1 files changed, 99 insertions(+), 34 deletions(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index f9dbcda..035b9b8 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1404,12 +1404,87 @@
</dd>
</dl>
+ <h4><a name="elementsAddress">Device Addresses</a></h4>
+
+ <p>
+ Many devices have an optional <code><address></code>
+ sub-element to describe where the device is placed on the
+ virtual bus presented to the guest. If an address is omitted on
+ input, libvirt will generate an appropriate address; but an
+ explicit address is required if more control over layout is
+ required. See below for device examples including an address
+ element.
+ </p>
+
+ <p>
+ Every address has a mandatory attribute <code>type</code> that
+ describes which bus the device is on. The choice of which
+ address to use for a given device is constrained in part by the
+ device and the architecture of the guest. For example,
+ a <code><disk></code> device
+ uses <code>type='disk'</code>, while
+ a <code><console></code> device would
+ use <code>type='pci'</code> on i686 or x86_64 guests,
+ or <code>type='spapr-vio'</code> on PowerPC64 pseries guests.
+ Each address type has further optional attributes that control
+ where on the bus the device will be placed:
+ </p>
+
+ <dl>
+ <dt><code>type='pci'</code></dt>
+ <dd>PCI addresses have the following additional
+ attributes: <code>domain</code> (a 2-byte hex integer, not
+ currently used by qemu), <code>bus</code> (a hex value between
+ 0 and 0xff, inclusive), <code>slot</code> (a hex value between
+ 0x0 and 0x1f, inclusive), and <code>function</code> (a value
+ between 0 and 7, inclusive). Also available is
+ the <code>multifunction</code> attribute, which controls
+ turning on the multifunction bit for a particular
+ slot/function in the PCI control register
+ (<span class="since">since 0.9.7, requires QEMU
+ 0.13</span>). <code>multifunction</code> defaults to 'off',
+ but should be set to 'on' for function 0 of a slot that will
+ have multiple functions used.
+ </dd>
+ <dt><code>type='drive'</code></dt>
+ <dd>Drive addresses have the following additional
+ attributes: <code>controller</code> (a 2-digit controller
+ number), <code>bus</code> (a 2-digit bus number),
+ and <code>unit</code> (a 2-digit unit number on the bus).
+ </dd>
+ <dt><code>type='virtio-serial'</code></dt>
+ <dd>Each virtio-serial address has the following additional
+ attributes: <code>controller</code> (a 2-digit controller
+ number), <code>bus</code> (a 2-digit bus number),
+ and <code>slot</code> (a 2-digit slot within the bus).
+ </dd>
+ <dt><code>type='ccid'</code></dt>
+ <dd>A CCID address, for smart-cards, has the following
+ additional attributes: <code>bus</code> (a 2-digit bus
+ number), and <code>slot</code> attribute (a 2-digit slot
+ within the bus). <span class="since">Since 0.8.8.</span>
+ <dt><code>type='usb'</code></dt>
+ <dd>USB addresses have the following additional
+ attributes: <code>bus</code> (a hex value between 0 and 0xfff,
+ inclusive), and <code>port</code> (a dotted notation of up to
+ four octets, such as 1.2 or 2.1.3.1).
+ </dd>
+ <dt><code>type='spapr-vio'</code></dt>
+ <dd>On PowerPC guests, devices are assigned on the SPAPR-VIO
+ bus, which is a flat 64-bit address space, where each address
+ should be aligned on a multiple of 0x1000. Each address has
+ the following additional attribute: <code>reg</code> (the hex
+ value address of the starting
+ register). <span class="since">Since 0.9.9.</span>
+ </dd>
+ </dl>
+
<h4><a name="elementsControllers">Controllers</a></h4>
<p>
- Many devices that have an <code><address></code>
- sub-element are designed to work with a controller to manage
- related devices. Normally, libvirt can automatically infer such
+ Depending on the guest architecture, some device busses can
+ appear more than once, with a group of virtual devices tied to a
+ virtual controller. Normally, libvirt can automatically infer such
controllers without requiring explicit XML markup, but sometimes
it is necessary to provide an explicit controller element.
</p>
@@ -1443,15 +1518,15 @@
A "usb" controller has an optional attribute <code>model</code>,
which is one of "piix3-uhci", "piix4-uhci", "ehci",
"ich9-ehci1", "ich9-uhci1", "ich9-uhci2", "ich9-uhci3",
- "vt82c686b-uhci" or "pci-ohci".
+ "vt82c686b-uhci" or "pci-ohci". The PowerPC64 "spapr-vio"
+ addresses do not have an associated controller.
</p>
<p>
For controllers that are themselves devices on a PCI or USB bus,
an optional sub-element <code><address></code> can specify
the exact relationship of the controller to its master bus, with
- semantics like any other device's <code>address</code>
- sub-element.
+ semantics <a href="#elementsAddress">given above</a>.
</p>
<p>
@@ -1608,19 +1683,9 @@
(starting with 0x) or octal (starting with 0) form.
For PCI devices the element carries 3 attributes allowing to designate
the device as can be found with the <code>lspci</code> or
- with <code>virsh nodedev-list</code>. The
- <code>bus</code> attribute allows the hexadecimal values 0 to ff, the
- <code>slot</code> attribute allows the hexadecimal values 0 to 1f, and
- the <code>function</code> attribute allows the hexadecimal values 0 to 7.
- The <code>multifunction</code> attribute controls turning on the
- multifunction bit for a particular slot/function in the PCI
- control register<span class="since">since 0.9.7, requires QEMU
- 0.13</span>. <code>multifunction</code> defaults to 'off', but
- should be set to 'on' for function 0 of a slot that will have
- multiple functions used.
- There is also an optional <code>domain</code> attribute for
- the PCI domain, with hexadecimal values 0 to ffff, but it is
- currently not used by qemu.</dd>
+ with <code>virsh
+ nodedev-list</code>. <a href="elementsAddress">See above</a> for
+ more details on the address element.
</dl>
<h4><a name="elementsRedir">Redirected devices</a></h4>
@@ -1756,12 +1821,9 @@
<p>
Each mode supports an optional
sub-element <code><address></code>, which fine-tunes the
- correlation between the smartcard and a ccid bus controller.
- If present, the element must have an attribute
- of <code>type='ccid'</code> as well as a <code>bus</code>
- attribute listing the index of the bus that the smartcard
- utilizes. An optional <code>slot</code> attribute lists which
- slot within the bus. For now, qemu only supports at most one
+ correlation between the smartcard and a ccid bus
+ controller, <a href="#elementsAddress">documented above</a>.
+ For now, qemu only supports at most one
smartcard, with an address of bus=0 slot=0.
</p>
@@ -1786,10 +1848,8 @@
each <code><interface></code> element has an
optional <code><address></code> sub-element that can tie
the interface to a particular pci slot, with
- attribute <code>type='pci'</code> and additional
- attributes <code>domain</code>, <code>bus</code>, <code>slot</code>,
- <code>function</code>, and <code>multifunction</code>
- <span class="since">since 0.9.7, requires QEMU 0.13</span> as appropriate.
+ attribute <code>type='pci'</code>
+ as <a href="#elementsAddress">documented above</a>.
</p>
<h5><a name="elementsNICSVirtual">Virtual network</a></h5>
@@ -2387,7 +2447,8 @@ qemu-kvm -net nic,model=? /dev/null
<p>
The <code>input</code> element has an optional
sub-element <code><address></code> which can tie the
- device to a particular PCI slot.
+ device to a particular PCI
+ slot, <a href="#elementsAddress">documented above</a>.
</p>
<h4><a name="elementsHub">Hub devices</a></h4>
@@ -2413,8 +2474,10 @@ qemu-kvm -net nic,model=? /dev/null
<p>
The <code>hub</code> element has an optional
- sub-element <code><address></code> which can tie the
- device to a particular controller.
+ sub-element <code><address></code>
+ with <code>type='usb'</code>which can tie the device to a
+ particular controller, <a href="#elementsAddress">documented
+ above</a>.
</p>
<h4><a name="elementsGraphics">Graphical framebuffers</a></h4>
@@ -2876,7 +2939,8 @@ qemu-kvm -net nic,model=? /dev/null
/dev/virtio-ports/$name (for more info, please see
<a href="http://fedoraproject.org/wiki/Features/VirtioSerial">http://fedoraproject.org/wiki/Features/VirtioSerial</a>). The
optional element <code>address</code> can tie the channel to a
- particular <code>type='virtio-serial'</code> controller.
+ particular <code>type='virtio-serial'</code>
+ controller, <a href="#elementsAddress">documented above</a>.
<span class="since">Since 0.7.7</span></dd>
<dt><code>spicevmc</code></dt>
@@ -3152,7 +3216,8 @@ qemu-kvm -net nic,model=? /dev/null
<p>
Each <code>sound</code> element has an optional
sub-element <code><address></code> which can tie the
- device to a particular PCI slot.
+ device to a particular PCI
+ slot, <a href="#elementsAddress">documented above</a>.
</p>
<h4><a name="elementsWatchdog">Watchdog device</a></h4>
--
1.7.7.3
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