On Thu, Apr 20, 2017 at 03:05:59PM +0200, Erik Skultety wrote: > There's lot more to document about the nodedev driver, besides PCI and > SR-IOV (even this might need to be extended), but let's start small-ish > and at least have a page for it linked from the drivers.html. > > Signed-off-by: Erik Skultety <eskultet@xxxxxxxxxx> > --- > docs/drivers.html.in | 6 +- > docs/drvnodedev.html.in | 184 ++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 189 insertions(+), 1 deletion(-) > create mode 100644 docs/drvnodedev.html.in > > diff --git a/docs/drivers.html.in b/docs/drivers.html.in > index be7483b9b..61993861e 100644 > --- a/docs/drivers.html.in > +++ b/docs/drivers.html.in > @@ -4,7 +4,11 @@ > <body> > <h1>Internal drivers</h1> > > - <ul id="toc"></ul> > + <ul> > + <li><a href="#hypervisor">Hypervisor drivers</a></li> > + <li><a href="#storage">Storage drivers</a></li> > + <li><a href="drvnodedev.html">Node device driver</a></li> > + </ul> > > <p> > The libvirt public API delegates its implementation to one or > diff --git a/docs/drvnodedev.html.in b/docs/drvnodedev.html.in > new file mode 100644 > index 000000000..ed185c3df > --- /dev/null > +++ b/docs/drvnodedev.html.in > @@ -0,0 +1,184 @@ > +<?xml version="1.0" encoding="UTF-8"?> > +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";> > +<html xmlns="http://www.w3.org/1999/xhtml";> > + <body> > + <h1>Host device management</h1> > + > + <p> > + Libvirt provides management of both physical and virtual host devices > + (historically also referred to as node devices) like USB, PCI, SCSI, and > + network devices. This also includes various virtualization capabilities > + which the aforementioned devices provide for utilization, for example > + SR-IOV, NPIV, MDEV, DRM, etc. <br/> > + <br/> You should use </p> and <p> instead of double <br/> if we are using paragraphs. > + The node device driver provides means to list and show details about host > + devices (<code>virsh nodedev-list</code>, > + <code>virsh nodedev-dumpxml</code>), which are generic and can be used > + with all devices. It also provides means to create and destroy devices > + (<code>virsh nodedev-create</code>, <code>virsh nodedev-destroy</code>) > + which are meant to be used to create virtual devices, currently only > + supported by NPIV > + (<a href="http://wiki.libvirt.org/page/NPIV_in_libvirt";>more info about NPIV)</a>). <br/> > + <br/> Same here. > + Devices on the host system are arranged in a tree-like hierarchy, with > + the root node being called <code>computer</code>. The node device driver > + supports two backends to manage the devices, HAL and udev, with the former > + being deprecated in favour of the latter.<br/> Either remove the single <br/> or replace it with a pair of </p> and <p> to end current paragraph and start a new one. > + The generic format of a host device XML can be seen below. > + To identify a device both within the host and the device tree hierarchy, > + the following elements are used: > + </p> > + <dl> > + <dt><code>name</code></dt> > + <dd> > + The device's name will be generated by libvirt using the subsystem, > + like pci and the device's sysfs basename. > + </dd> > + <dt><code>path</code></dt> > + <dd> > + Fully qualified sysfs path to the device. > + </dd> > + <dt><code>parent</code></dt> > + <dd> > + This element identifies the parent node in the device hierarchy. The > + value of the element will correspond with the device parent's > + <code>name</code> element or <code>computer</code> if the device does > + not have any parent. > + </dd> > + <dt><code>driver</code></dt> > + <dd> > + This elements reports the driver in use for this device. The presence > + of this element in the output XML depends on whether the underlying > + device manager (most likely udev) exposes information about the > + driver. > + </dd> > + <dt><code>capability</code></dt> > + <dd> > + Describes the device in terms of feature support. The element has one > + mandatory attribute <code>type</code> the value of which determines > + the type of the device. Currently recognized values for the attribute > + are: > + <code>system</code>, > + <code>pci</code>, > + <code>usb</code>, > + <code>usb_device</code>, > + <code>net</code>, > + <code>scsi</code>, > + <code>scsi_host</code> (<span class="since">Since 0.4.7</span>), > + <code>fc_host</code>, > + <code>vports</code>, > + <code>scsi_target</code> (<span class="since">Since 0.7.3</span>), > + <code>storage</code> (<span class="since">Since 1.0.4</span>), > + <code>scsi_generic</code> (<span class="since">Since 1.0.7</span>), > + <code>drm</code> (<span class="since">Since 3.1.0</span>), and > + <code>mdev</code> (<span class="since">Since 3.2.0</span>). > + This element can be nested in which case it further specifies a > + device's capability. Refer to specific device types to see more values > + for the <code>type</code> attribute which are exclusive. > + </dd> > + </dl> > + > + <h2>Basic structure of a node device</h2> > + <pre> > +<device> > + <name>pci_0000_00_17_0</name> > + <path>/sys/devices/pci0000:00/0000:00:17.0</path> > + <parent>computer</parent> > + <driver> > + <name>ahci</name> > + </driver> > + <capability type='pci'> > +... > + </capability> > +</device></pre> > + > + <ul id="toc"/> > + > + <h2><a name="PCI">PCI host devices</a></h2> > + <dl> > + <dt><code>capability</code></dt> > + <dd> > + When used as top level element, the supported values for the > + <code>type</code> attribute are <code>pci</code> and > + <code>phys_function</code> (see <a href="#SRIOVCap">SR-IOV below</a>). > + </dd> > + </dl> > + <pre> > +<device> > + <name>pci_0000_04_00_1</name> > + <path>/sys/devices/pci0000:00/0000:00:06.0/0000:04:00.1</path> > + <parent>pci_0000_00_06_0</parent> > + <driver> > + <name>igb</name> > + </driver> > + <capability type='pci'> > + <domain>0</domain> > + <bus>4</bus> > + <slot>0</slot> > + <function>1</function> > + <product id='0x10c9'>82576 Gigabit Network Connection</product> > + <vendor id='0x8086'>Intel Corporation</vendor> > + <iommuGroup number='15'> > + <address domain='0x0000' bus='0x04' slot='0x00' function='0x1'/> > + </iommuGroup> > + <numa node='0'/> > + <pci-express> > + <link validity='cap' port='1' speed='2.5' width='2'/> > + <link validity='sta' speed='2.5' width='2'/> > + </pci-express> > + </capability> > +</device></pre> > + > + <p> > + The XML format for a PCI device stays the same for any further > + capabilities it supports, a single nested <code><capability></code> > + element will be included for each capability the device supports. > + </p> > + > + <h3><a name="SRIOVCap">SR-IOV capability</a></h3> > + <p> > + Single root input/output virtualization (SR-IOV) allows sharing of the > + PCIe resources by multiple virtual environments. That is achieved by > + slicing up a single full-featured physical resource called physical > + function (PF) into multiple devices called virtual functions (VFs) sharing > + their configuration with the underlying PF. Despite the SR-IOV > + specification, the amount of VFs that can be created on a PF varies among > + manufacturers.<br/> > + <br/> Replace double <br/> with </p> and <p>. > + Suppose the NIC <a href="#PCI">above</a> was also SR-IOV capable, it would > + also include a nested > + <code><capability></code> element enumerating all virtual > + functions available on the physical device (physical port) like in the > + example below. > + </p> > + > + <pre> > +<capability type='pci'> > +... > + <capability type='virt_functions' maxCount='7'> > + <address domain='0x0000' bus='0x04' slot='0x10' function='0x1'/> > + <address domain='0x0000' bus='0x04' slot='0x10' function='0x3'/> > + <address domain='0x0000' bus='0x04' slot='0x10' function='0x5'/> > + <address domain='0x0000' bus='0x04' slot='0x10' function='0x7'/> > + <address domain='0x0000' bus='0x04' slot='0x11' function='0x1'/> > + <address domain='0x0000' bus='0x04' slot='0x11' function='0x3'/> > + <address domain='0x0000' bus='0x04' slot='0x11' function='0x5'/> > + </capability> > +... > +</capability></pre> > + <p> > + A SR-IOV child device on the other hand, would then report its top level > + capability type as a physical function instead: > + </p> > + > + <pre> > +<device> > +... > + <capability type='phys_function'> > + <address domain='0x0000' bus='0x04' slot='0x00' function='0x0'/> > + </capability> > +... > +<device></pre> > + > + </body> > +</html> > -- > 2.12.2 I'm not a native speaker but the text makes sense and having something is definitely better than having no documentation at all. ACK Pavel
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