mdevctl.8

.\" mdevctl - Mediated device management utility
.TH mdevctl 8
.SH NAME
mdevctl, lsmdev \- Mediated device management utility
.SH SYNOPSIS
\fBmdevctl\fR {COMMAND} [OPTIONS...]\fR

.SH DESCRIPTION

\fBmdevctl\fR is a utility for managing and persisting devices in the
mediated device device framework of the Linux kernel.  Mediated
devices are sub-devices of a parent device (ex. a vGPU) which
can be dynamically created and potentially used by drivers like
vfio-mdev for assignment to virtual machines.

.SH OPTIONS

.PP
The following options are understood:

.PP
\fB--addattr=ATTRIBUTE\fR
.RS 4
Add an attribute \fIATTRIBUTE\fR. Valid for the \fBmodify\fR
command.
.RE

.PP
\fB-a|--auto\fR
.RS 4
Automatically start the device on parent availability. Valid for
\fBdefine\fR and \fBmodify\fR commands.
.RE

.PP
\fB-d|--defined\fR
.RS 4
List all defined devices, even if not active. Valid for the \fBlist\fR
command.
.RE

.PP
\fB--delattr\fR
.RS 4
Delete an attribute entry. Valid for the \fBmodify\fR command.
.RE

.PP
\fB--dumpjson\fR
.RS 4
Dump the configuration for a device in JSON format when filtered to
as single device and used with the \fBlist\fR command.  When used
with the \fBtypes\fR command, output machine readable type information.
.RE

.PP
\fB-i|--index=INDEX\fR
.RS 4
Act on the attribute \fIINDEX\fR. Valid for the \fBmodify\fR command.
.RE

.PP
\fB--jsonfile=FILE\fR
.RS 4
Read the configuration for a device from a JSON file \fIFILE\fR.
Valid for the \fBdefine\fR and \fBstart\fR commands.
.RE

.PP
\fB-m|--manual\fR
.RS 4
Do not start a device automatically on parent availability. Valid
for the \fBmodify\fR command.
.RE

.PP
\fB-p|--parent=PARENT\fR
.RS 4
Specify or identify the device by its parent device.
.RE

.PP
\fB-t|--type=TYPE\fR
.RS 4
Specify or identify the device by its type.
.RE

.PP
\fB-u|--uuid=UUID\fR
.RS 4
Specify or identify the device by its UUID.
.RE

.PP
\fB--value=VALUE\fR
.RS 4
Set an attribute to \fIVALUE\fR, in the format accepted by the attribute.
Valid for the \fBmodify\fR command.
.RE

.PP
\fB-v|--verbose\fR
.RS 4
Increase output verbosity, currently only adds attribute output to the
\fBlist\fR command.
.RE

.PP
\fB-V|--version\fR
.RS 4
Print mdevctl version.
.RE

.SH COMMANDS

.PP
The following commands are understood:

.PP
\fBdefine\fR \fIDEVICESPEC\fR
.RS 4
Define a config for an mdev device, identified either by an UUID (if
the device already exists), or by the parent device and either the type
or a JSON configuration file, and, optionally, the UUID. If no UUID is
specified, one is autogenerated and printed. If no file is used,
\fI-a|--auto\fR may be used to specify that the device should be started
automatically.
.RE

.PP
\fBlist\fR
.RS 4
List mdev devices. With no options, currently running devices are listed.
With \fB-d|--defined\fR, previously defined devices are listed.
Can be restricted to list only devices for a given parent or UUID. With
\fB--dumpjson\fR output is provided in machine readable JSON format.
When a UUID is provided and the output results in a single device, the
JSON output format is compatible with the configuration file format.
.RE

.PP
\fBmodify\fR \fIDEVICESPEC\fR
.RS 4
Modify the configuration for an mdev device, identified via its UUID
and optionally its parent.
Type and startup mode (auto or manual) can be modified by this command.
Attributes can be added or deleted. Attributes to be deleted must be
specified by their index; if an attribute is specified without an
index, it is appended at the end of the attribute list.
Running devices are unaffected by this command; changes in the configuration
are applied the next time the device is started.
.RE

.PP
\fBstart\fR \fIDEVICESPEC\fR
.RS 4
Start a mediated device. This command can be used to start either a
previously-defined device or a newly-created transient device.

If the UUID and optional parent argument matches an existing device definition,
then the existing device will be started. It is an error to specify a device
type that conflicts with the existing device definition.

If the UUID argument is omitted or if the specified UUID and parent does not
match an existing device definition, a new transient device will be started.
If the UUID is omitted, a new UUID will be automatically generated. When
starting a new transient device, the parent and device type must be specified.
A \fB--jsonfile\fR may replace the \fB--type\fR specification and also include
additional attributes in JSON format to be applied to the started device.
.RE

.PP
\fBstop\fR \fIDEVICESPEC\fR
.RS 4
Stop an mdev device, specified via its UUID.
.RE

.PP
\fBtypes\fR
.RS 4
List the mdev device types known to the system by parent device.  Output
may be limited to a single parent device with the \fB-p|--parent\fR option.
JSON output format is used with the \fB--dumpjson\fR option.
.RE

.PP
\fBundefine\fR \fIDEVICESPEC\fR
.RS 4
Undefine, or remove the configuration for an mdev device, specified by
its UUID and optionally its parent. If a UUID exists for multiple
parents, all of them will be removed unless restricted to a single parent.
Running devices are unaffected by this command.
.RE

.SH "NOTE ON DEVICE SPECIFICATION"

For a given UUID, only one device with that UUID may be running at the
same time. However, it is possible to define multiple devices with the
same UUID under different parent devices. Therefore, it is sometimes
necessary to specify the parent device alongside the UUID to uniquely
identify a device.

.SH "EXIT STATUS"
On success, 0 is returned, a non-zero failure code otherwise.

.SH EXAMPLES

.nf
List running mdev devices:

.EX
# mdevctl list
85006552-1b4b-45ef-ad62-de05be9171df 0000:00:02.0 i915-GVTg_V4_4
83c32df7-d52e-4ec1-9668-1f3c7e4df107 0000:00:02.0 i915-GVTg_V4_8 (defined)
.EE

List defined mdev devices:

.EX
# mdevctl list -d
83c32df7-d52e-4ec1-9668-1f3c7e4df107 0000:00:02.0 i915-GVTg_V4_8 auto
b0a3989f-8138-4d49-b63a-59db28ec8b48 0000:00:02.0 i915-GVTg_V4_8 auto
5cf14a12-a437-4c82-a13f-70e945782d7b 0000:00:02.0 i915-GVTg_V4_4 manual
.EE

List mdev types supported on the host system:

.EX
# mdevctl types
0000:00:02.0
  i915-GVTg_V4_2
    Available instances: 1
    Device API: vfio-pci
    Description: low_gm_size: 256MB high_gm_size: 1024MB fence: 4 resolution: 1920x1200 weight: 8 
  i915-GVTg_V4_1
    Available instances: 0
    Device API: vfio-pci
    Description: low_gm_size: 512MB high_gm_size: 2048MB fence: 4 resolution: 1920x1200 weight: 16 
  i915-GVTg_V4_8
    Available instances: 4
    Device API: vfio-pci
    Description: low_gm_size: 64MB high_gm_size: 384MB fence: 4 resolution: 1024x768 weight: 2 
  i915-GVTg_V4_4
    Available instances: 3
    Device API: vfio-pci
    Description: low_gm_size: 128MB high_gm_size: 512MB fence: 4 resolution: 1920x1200 weight: 4 
.EE

Modify a defined device from automatic start to manual:

.EX
# mdevctl modify --uuid 83c32df7-d52e-4ec1-9668-1f3c7e4df107 --manual
# mdevctl list -d
83c32df7-d52e-4ec1-9668-1f3c7e4df107 0000:00:02.0 i915-GVTg_V4_8 manual
b0a3989f-8138-4d49-b63a-59db28ec8b48 0000:00:02.0 i915-GVTg_V4_8 auto
5cf14a12-a437-4c82-a13f-70e945782d7b 0000:00:02.0 i915-GVTg_V4_4 manual
.EE

Stop a running mdev device:

.EX
# mdevctl stop -u 83c32df7-d52e-4ec1-9668-1f3c7e4df107
.EE

Start an mdev device that is not defined:

.EX
# uuidgen
6eba5b41-176e-40db-b93e-7f18e04e0b93
# mdevctl start -u 6eba5b41-176e-40db-b93e-7f18e04e0b93 -p 0000:00:02.0 --type i915-GVTg_V4_1
# mdevctl list
85006552-1b4b-45ef-ad62-de05be9171df 0000:00:02.0 i915-GVTg_V4_4
6eba5b41-176e-40db-b93e-7f18e04e0b93 0000:00:02.0 i915-GVTg_V4_1
.EE

Promote the new created mdev to a defined device:

.EX
# mdevctl define --uuid 6eba5b41-176e-40db-b93e-7f18e04e0b93
# mdevctl list -d
83c32df7-d52e-4ec1-9668-1f3c7e4df107 0000:00:02.0 i915-GVTg_V4_8 manual
6eba5b41-176e-40db-b93e-7f18e04e0b93 0000:00:02.0 i915-GVTg_V4_1 manual
b0a3989f-8138-4d49-b63a-59db28ec8b48 0000:00:02.0 i915-GVTg_V4_8 auto
5cf14a12-a437-4c82-a13f-70e945782d7b 0000:00:02.0 i915-GVTg_V4_4 manual
.EE

.SS "ADVANCED EXAMPLES (ATTRIBUTES AND JSON)"

.EX
# mdevctl list -d
783e6dbb-ea0e-411f-94e2-717eaad438bf matrix vfio_ap-passthrough manual
.EE

Add some attributes:

.EX
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --addattr=assign_adapter --value=5
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --addattr=assign_adapter --value=6
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --addattr=assign_domain --value=0xab
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --addattr=assign_control_domain --value=0xab
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --addattr=assign_domain --value=4
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --addattr=assign_control_domain --value=4
# mdevctl list -dv
783e6dbb-ea0e-411f-94e2-717eaad438bf matrix vfio_ap-passthrough manual
  Attrs:
    @{0}: {"assign_adapter":"5"}
    @{1}: {"assign_adapter":"6"}
    @{2}: {"assign_domain":"0xab"}
    @{3}: {"assign_control_domain":"0xab"}
    @{4}: {"assign_domain":"4"}
    @{5}: {"assign_control_domain":"4"}
.EE

Dump the JSON configuration:

.EX
# mdevctl list -d -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --dumpjson
{
  "mdev_type": "vfio_ap-passthrough",
  "start": "manual",
  "attrs": [
    {
      "assign_adapter": "5"
    },
    {
      "assign_adapter": "6"
    },
    {
      "assign_domain": "0xab"
    },
    {
      "assign_control_domain": "0xab"
    },
    {
      "assign_domain": "4"
    },
    {
      "assign_control_domain": "4"
    }
  ]
}
.EE

Remove some attributes:

.EX
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --delattr --index=5
# mdevctl modify -u 783e6dbb-ea0e-411f-94e2-717eaad438bf --delattr --index=4
# mdevctl list -dv
783e6dbb-ea0e-411f-94e2-717eaad438bf matrix vfio_ap-passthrough manual
  Attrs:
    @{0}: {"assign_adapter":"5"}
    @{1}: {"assign_adapter":"6"}
    @{2}: {"assign_domain":"0xab"}
    @{3}: {"assign_control_domain":"0xab"}
.EE

Define an mdev device from a file:

.EX
# cat vfio_ap_device.json
{
  "mdev_type": "vfio_ap-passthrough",
  "start": "manual",
  "attrs": [
    {
      "assign_adapter": "5"
    },
    {
      "assign_domain": "0x47"
    },
    {
      "assign_domain": "0xff"
    }
  ]
}
# mdevctl define -p matrix --jsonfile vfio_ap_device.json
e2e73122-cc39-40ee-89eb-b0a47d334cae
# mdevctl list -dv
783e6dbb-ea0e-411f-94e2-717eaad438bf matrix vfio_ap-passthrough manual
  Attrs:
    @{0}: {"assign_adapter":"5"}
    @{1}: {"assign_adapter":"6"}
    @{2}: {"assign_domain":"0xab"}
    @{3}: {"assign_control_domain":"0xab"}
e2e73122-cc39-40ee-89eb-b0a47d334cae matrix vfio_ap-passthrough manual
  Attrs:
    @{0}: {"assign_adapter":"5"}
    @{1}: {"assign_domain":"0x47"}
    @{2}: {"assign_domain":"0xff"}
.EE

.SH FILES
\fI/etc/mdevctl.d/*\fR

Configuration files are in one subdirectory per parent device and named
by UUID.

.SH "CONFIGURATION FILE FORMAT"

Configuration files are in JSON. Attributes in \fB"attrs"\fR are optional.

.EX
{
  "mdev_type": \fI"TYPE"\fR,
  "start": \fI"auto|manual"\fR,
  "attrs": [
    {
      \fI"attribute0"\fR: \fI"VALUE"\fR
    },
    {
      \fI"attribute1"\fR: \fI"VALUE"\fR
    }
  ]
}
.EE

.SH "SEE ALSO"
\fBudev\fR(7)
\fBudevadm\fR(8)
\fBdriverctl\fR(8)