Signed-off-by: Erik Skultety <eskultet@xxxxxxxxxx> --- docs/drvnodedev.html.in | 91 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) diff --git a/docs/drvnodedev.html.in b/docs/drvnodedev.html.in index ed185c3df3..776c88cc87 100644 --- a/docs/drvnodedev.html.in +++ b/docs/drvnodedev.html.in @@ -180,5 +180,96 @@ ... <device></pre> + <h3><a name="MDEVCap">MDEV capability</a></h3> + <p> + A PCI device capable of creating mediated devices will include a nested + capability mdev which enumerates all the supported mdev types on the + physical device, along with the type attributes available through sysfs. + For a more info about mediated devices, refer to the + <a href="#MDEV">paragraph below</a>. + </p> + +<pre> +<device> +... + <driver> + <name>nvidia</name> + </driver> + <capability type='pci'> +... + <capability type='mdev'> + <type id='nvidia-11'> + <name>GRID M60-0B</name> + <description>num_heads=2, frl_config=45, framebuffer=512M, + max_resolution=2560x1600, max_instance=16</description> + <device_api>vfio-pci</device_api> + <available_instances>16</available_instances> + </type> + <!-- Here would come the rest of the available mdev types --> + </capability> +... + </capability> +</device></pre> + + <h2><a name="MDEV">Mediated devices (MDEVs)</a></h2> + <p> + Mediated devices (<span class="since">Since 3.2.0</span>) are software + devices defining resource allocation on the backing physical device which + in turn allows the parent physical device's resources to be divided into + several mediated devices, thus sharing the physical device's performance + among multiple guests. Unlike SR-IOV however, where a PCIe device appears + as multiple separate PCIe devices on the host's PCI bus, mediated devices + only appear on the mdev virtual bus. Therefore, no detach/reattach + procedure from/to the host driver procedure is involved even though + mediated devices are used in a direct device assignment manner.<br/> + <br/> + At the moment, libvirt can only list the available mediated devices on the + host and display all information libvirt can gather about them, see the + examples below. Because mediated devices are instantiated from vendor + specific templates, simply called 'types', information about the resource + allocation for a specific type is contained within the backing physical + parent device (see <a href="#PCI">PCI host devices</a> for an example). + </p> + + <h3>Example of a mediated device</h3> + <pre> +<device> + <name>mdev_4b20d080_1b54_4048_85b3_a6a62d165c01</name> + <path>/sys/devices/pci0000:00/0000:00:02.0/4b20d080-1b54-4048-85b3-a6a62d165c01</path> + <parent>pci_0000_06_00_0</parent> + <driver> + <name>vfio_mdev</name> + </driver> + <capability type='mdev'> + <type id='nvidia-11'/> + <iommuGroup number='12'/> + <capability/> +<device/></pre> + + <p> + To see the supported mediated device types on a specific physical device + use the following: + </p> + + <pre> +$ ls /sys/class/mdev_bus/<device>/mdev_supported_types</pre> + + <p> + To manually instantiate a mediated device, use one of the following as a + reference: + </p> + + <pre> +$ uuidgen > /sys/class/mdev_bus/<device>/mdev_supported_types/<type>/create +... +$ echo <UUID> > /sys/class/mdev_bus/<device>/mdev_supported_types/<type>/create</pre> + + <p> + Manual removal of a mediated device is then performed as follows: + </p> + + <pre> +$ echo 1 > /sys/bus/mdev/devices/<uuid>/remove</pre> + </body> </html> -- 2.12.2 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
