From nobody Mon Feb 9 01:21:58 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1490792448771817.5185770727862; Wed, 29 Mar 2017 06:00:48 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CA1DD64DB9; Wed, 29 Mar 2017 13:00:46 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8E62B81C0A; Wed, 29 Mar 2017 13:00:46 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 2D24E18523CB; Wed, 29 Mar 2017 13:00:46 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id v2TCpidL010151 for ; Wed, 29 Mar 2017 08:51:44 -0400 Received: by smtp.corp.redhat.com (Postfix) id 65EB8962B7; Wed, 29 Mar 2017 12:51:44 +0000 (UTC) Received: from beluga.usersys.redhat.com (dhcp129-94.brq.redhat.com [10.34.129.94]) by smtp.corp.redhat.com (Postfix) with ESMTP id BAF897E66B; Wed, 29 Mar 2017 12:51:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CA1DD64DB9 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=libvir-list-bounces@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com CA1DD64DB9 From: Erik Skultety To: libvir-list@redhat.com Date: Wed, 29 Mar 2017 14:51:21 +0200 Message-Id: <6d09fc1bc00b1bf78a5855f2d43e67f8b58cad5d.1490791809.git.eskultet@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-loop: libvir-list@redhat.com Cc: Erik Skultety Subject: [libvirt] [RFC PATCH 11/11] docs: Document the mediated devices within the nodedev driver X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 29 Mar 2017 13:00:47 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" Signed-off-by: Erik Skultety --- 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> =20 +

MDEV capability

+

+ A PCI device capable of creating mediated devices will include a nes= ted + capability mdev which enumerates all the supported mdev types on the + physical device, along with the type attributes available through sy= sfs. + For a more info about mediated devices, refer to the + paragraph below. +

+ +
+<device>
+...
+  <driver>
+    <name>nvidia</name>
+  </driver>
+  <capability type=3D'pci'>
+...
+    <capability type=3D'mdev'>
+      <type id=3D'nvidia-11'>
+        <name>GRID M60-0B</name>
+        <description>num_heads=3D2, frl_config=3D45, framebuffer=3D5=
12M,
+        max_resolution=3D2560x1600, max_instance=3D16</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>
+ +

Mediated devices (MDEVs)

+

+ Mediated devices (Since 3.2.0) are soft= ware + 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 perform= ance + among multiple guests. Unlike SR-IOV however, where a PCIe device ap= pears + as multiple separate PCIe devices on the host's PCI bus, mediated de= vices + 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.
+
+ 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 res= ource + allocation for a specific type is contained within the backing physi= cal + parent device (see PCI host devices for an exam= ple). +

+ +

Example of a mediated device

+ 
+<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=3D'mdev'>
+    <type id=3D'nvidia-11'/>
+    <iommuGroup number=3D'12'/>
+  <capability/>
+<device/>
+ +

+ To see the supported mediated device types on a specific physical de= vice + use the following: +

+ + 
+$ ls /sys/class/mdev_bus/<device>/mdev_supported_types
+ +

+ To manually instantiate a mediated device, use one of the following = as a + reference: +

+ + 
+$ uuidgen > /sys/class/mdev_bus/<device>/mdev_supported_types/<=
;type>/create
+...
+$ echo <UUID> > /sys/class/mdev_bus/<device>/mdev_supported=
_types/<type>/create
+ +

+ Manual removal of a mediated device is then performed as follows: +

+ + 
+$ echo 1 > /sys/bus/mdev/devices/<uuid>/remove
+ --=20 2.12.2 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list