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.Dd April 20, 2021
.Dt BHYVE_CONFIG 5
.Os
.Sh NAME
.Nm bhyve_config
.Nd "bhyve configuration variables"
.Sh DESCRIPTION
.Xr bhyve 8
uses a hierarchical tree of configuration variables to describe global and
per-device settings.
Internal nodes in this tree do not have a value,
only leaf nodes have values.
This manual describes the configuration variables understood by
.Xr bhyve 8 .
If additional variables are defined,
.Xr bhyve 8
will ignore them and will not emit errors for unknown variables.
However, these additional variables can be referenced by other
variables as described below.
.Sh VARIABLE VALUES
Configuration variable values are stored as strings.
A configuration variable value may refer to one or more other
configuration values by name.
Instances of the pattern
.Sq % Ns Pq Ar var
are replaced by the value of the configuration variable
.Va var .
To avoid unwanted expansion,
.Sq %
characters can be escaped by a leading
.Sq % .
For example,
if a configuration variable
.Va disk
uses the value
.Pa /dev/zvol/bhyve/%(name) ,
then the final value of the
.Va disk
variable will be set to the path of a ZFS volume whose name matches
the name of the virtual machine on the pool
.Pa bhyve .
.Pp
Some configuration variables may be interpreted as a boolean value.
For those variables the following case-insensitive values may be used to
indicate true:
.Pp
.Bl -bullet -offset indent -compact
.It
true
.It
on
.It
yes
.It
1
.El
.Pp
The following values may be used to indicate false:
.Pp
.Bl -bullet -offset indent -compact
.It
false
.It
off
.It
no
.It
0
.El
.Pp
Some configuration variables may be interperted as an integer.
For those variables,
any syntax supported by
.Xr strtol 3
may be used.
.Sh GLOBAL SETTINGS
.Ss Architecture Neutral Settings
.Bl -column "memory.guest_in_core" "integer" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va name Ta string Ta Ta
The name of the VM.
.It Va cpus Ta integer Ta 1 Ta
The total number of virtual CPUs.
.It Va cores Ta integer Ta 1 Ta
The number of virtual cores in each virtual socket.
.It Va threads Ta integer Ta 1 Ta
The number of virtual CPUs in each virtual core.
.It Va sockets Ta integer Ta 1 Ta
The number of virtual sockets.
.It Va memory.guest_in_core Ta bool Ta false Ta
Include guest memory in core file.
.It Va memory.size Ta string Ta 256M Ta
Guest physical memory size in bytes.
The value must be formatted as described in
.Xr expand_number 3 .
.It Va memory.wired Ta bool Ta false Ta
Wire guest memory.
.It Va acpi_tables Ta bool Ta false Ta
Generate ACPI tables.
.It Va destroy_on_poweroff Ta bool Ta false Ta
Destroy the VM on guest-initiated power-off.
.It Va gdb.port Ta integer Ta 0 Ta
TCP port number for the debug server.
If this is set to a non-zero value, a debug server
will listen for connections on this port.
.It Va gdb.wait Ta bool Ta false Ta
If the debug server is enabled, wait for a debugger to connect
before starting the guest.
.It Va rtc.use_localtime Ta bool Ta true Ta
The real time clock uses the local time of the host.
If this is set to false, the real time clock uses UTC.
.It Va uuid Ta string Ta Ta
The universally unique identifier (UUID) to use in the guest's
System Management BIOS System Information structure.
If an explicit value is not set, a valid UUID is generated from
the host's hostname and the VM name.
.It Va virtio_msix Ta bool Ta true Ta
Use MSI-X interrupts for PCI VirtIO devices.
If set to false, MSI interrupts are used instead.
.It Va config.dump Ta bool Ta false Ta
If this value is set to true after
.Xr bhyve 8
has finished parsing command line options,
then
.Xr bhyve 8
will write all of its configuration variables to stdout and exit.
No VM will be started.
.El
.Ss x86-Specific Settings
.Bl -column "x86.vmexit_on_pause" "integer" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va x86.mptable Ta bool Ta true Ta
Generate an MPTable.
.It Va x86.x2apic Ta bool Ta false Ta
Configure guest's local APICs in x2APIC mode.
.It Va x86.strictio Ta bool Ta false Ta
Exit if a guest accesses an I/O port that is not emulated.
By default, writes are ignored and reads return all bits set.
.It Va x86.strictmsr Ta bool Ta true Ta
Inject a general protection fault if a guest accesses a Model Specific
Register (MSR) that is not emulated.
If this is false, writes are ignored and reads return zero.
.It Va x86.vmexit_on_hlt Ta bool Ta false Ta
Force a VM exit when a guest CPU executes the
.Dv HLT
instruction.
This allows idle guest CPUs to yield the host CPU.
.It Va x86.vmexit_on_pause Ta bool Ta false Ta
Force a VM exit when a guest CPU executes the
.Dv PAUSE
instruction.
.El
.Sh DEVICE SETTINGS
Device settings are stored under a device node.
The device node's name is set by the parent bus of the device.
.Ss PCI Device Settings
PCI devices are described by a device node named
.Dq pci Ns Ar bus . Ns Ar slot . Ns Ar function
where each of
.Ar bus ,
.Ar slot ,
and
.Ar function
are formatted as decimal values with no padding.
All PCI device nodes must contain a configuration variable named
.Dq device
which specifies the device model to use.
The following PCI device models are supported:
.Bl -tag -indent
.It Li hostbridge
Provide a simple PCI-Host bridge device.
This is usually configured at pci0:0:0 and is required by most guest
operating systems.
.It Li ahci
AHCI storage controller.
.It Li e1000
Intel e82545 network interface.
.It Li fbuf
VGA framebuffer device attached to VNC server.
.It Li lpc
LPC PCI-ISA bridge with COM1-COM4 16550 serial ports,
a boot ROM,
and an optional debug/test device.
This device must be configured on bus 0.
.It Li hda
High Definition audio controller.
.It Li nvme
NVM Express (NVMe) controller.
.It Li passthru
PCI pass-through device.
.It Li uart
PCI 16550 serial device.
.It Li virtio-9p
VirtIO 9p (VirtFS) interface.
.It Li virtio-blk
VirtIO block storage interface.
.It Li virtio-console
VirtIO console interface.
.It Li virtio-input
VirtIO input interface.
.It Li virtio-net
VirtIO network interface.
.It Li virtio-rnd
VirtIO RNG interface.
.It Li virtio-scsi
VirtIO SCSI interface.
.It Li xhci
Extensible Host Controller Interface (XHCI) USB controller.
.El
.Ss USB Device Settings
USB controller devices contain zero or more child USB devices
attached to slots.
Each USB device stores its settings in a node named
.Dq slot. Ns Va N
under the controller's device node.
.Va N
is the number of the slot to which the USB device is attached.
Note that USB slot numbers begin at 1.
All USB device nodes must contain a configuration variable named
.Dq device
which specifies the device model to use.
The following USB device models are supported:
.Bl -tag -indent
.It Li tablet
A USB tablet device which provides precise cursor synchronization
when using VNC.
.El
.Ss Block Device Settings
Block devices use the following settings to configure their backing store.
These settings are stored in the configuration node of the respective device.
.Bl -column "sectorsize" "logical[/physical]" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It path Ta string Ta Ta
The path of the file or disk device to use as the backing store.
.It nocache Ta bool Ta false Ta
Disable caching on the backing file by opening the backing file with
.Dv O_DIRECT .
.It nodelete Ta bool Ta false Ta
Disable emulation of guest trim requests via
.Dv DIOCGDELETE
requests.
.It sync Ta bool Ta false Ta
Write changes to the backing file with synchronous writes.
.It direct Ta bool Ta false Ta
An alias for
.Va sync .
.It ro Ta bool Ta false Ta
Disable writes to the backing file.
.It sectorsize Ta Va logical Ns Op / Ns Va physical Ta Ta
Specify the logical and physical sector size of the emulated disk.
If the physical size is not specified,
it is equal to the logical size.
.El
.Ss Network Backend Settings
Network devices use the following settings to configure their backend.
The backend is responsible for passing packets between the device model
and a desired destination.
Configuring a backend requires setting the
.Va backend
variable to one of the following values:
.Bl -tag
.It tap Ns Va N
Use the named
.Xr tap 4
interface as the backend.
.It vmnet Ns Va N
Use the named
.Xr vmnet 4
interface as the backend.
.It netgraph
Use a
.Xr netgraph 4
socket hook as the backend.
This backend uses the following additional variables:
.Bl -column "peerhook" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va path Ta string Ta Ta
The name of the
.Xr netgraph 4
destination node.
.It Va peerhook Ta string Ta Ta
The name of the destination hook.
.It Va socket Ta string Ta Ta
The name of the created
.Xr ng_socket 4
node.
.It Va hook Ta string Ta vmlink Ta
The name of the source hook on the created
.Xr ng_socket 4
node.
.El
.It netmap: Ns Va interface
Use
.Xr netmap 4
on a network interface as the backend.
.It vale Ns Va bridge : Ns Va port
Use a port on a
.Xr vale 4
bridge as the backend.
.El
.Ss UART Device Settings
.Bl -column "Name" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va path Ta path Ta Ta
Backend device for the serial port.
Either the pathname of a character device or
.Dq stdio
to use standard input and output of the
.Xr bhyve 8
process.
.El
.Ss Host Bridge Settings
.Bl -column "vendor" "integer" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va vendor Ta integer Ta 0x1275 Ta
PCI vendor ID.
.It Va devid Ta integer Ta 0x1275 Ta
PCI device ID.
.El
.Ss AHCI Controller Settings
AHCI controller devices contain zero or more ports each of which
provides a storage device.
Each port stores its settings in a node named
.Dq port. Ns Va N
under the controller's device node.
The
.Va N
values are formatted as successive decimal values starting with 0.
In addition to the block device settings described above, each
port supports the following settings:
.Bl -column "model" "integer" "generated"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va type Ta string Ta Ta
The type of storage device to emulate.
Must be set to either
.Dq cd
or
.Dq hd .
.It Va nmrr Ta integer Ta 0 Ta
Nominal Media Rotation Rate, also known as RPM.
A value 1 of indicates a device with no rate such as a Solid State Disk.
.It Va ser Ta string Ta generated Ta
Serial number of up to twenty characters.
A default serial number is generated using a hash of the backing
store's pathname.
.It Va rev Ta string Ta 001 Ta
Revision number of up to eight characters.
.It Va model Ta string Ta Ta
Model number of up to forty characters.
Separate default model strings are used for
.Dq cd
and
.Dq hd
device types.
.El
.Ss e1000 Settings
In addition to the network backend settings,
Intel e82545 network interfaces support the following variables:
.Bl -column "Name" "MAC address" "generated"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va mac Ta MAC address Ta generated Ta
MAC address.
If an explicit address is not provided,
a MAC address is generated from a hash of the device's PCI address.
.El
.Ss Frame Buffer Settings
.Bl -column "password" "[IP:]port" "127.0.0.1:5900"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va wait Ta bool Ta false Ta
Wait for a remote connection before starting the VM.
.It Va rfb Ta Oo Ar IP Ns : Oc Ns Ar port Ta 127.0.0.1:5900 Ta
TCP address to listen on for remote connections.
The IP address must be given as a numeric address.
IPv6 addresses must be enclosed in square brackets and
support scoped identifiers as described in
.Xr getaddrinfo 3 .
A bare port number may be given in which case the IPv4
localhost address is used.
.It Va vga Ta string Ta io Ta
VGA configuration.
More details are provided in
.Xr bhyve 8 .
.It Va w Ta integer Ta 1024 Ta
Frame buffer width in pixels.
.It Va h Ta integer Ta 768 Ta
Frame buffer height in pixels.
.It Va password Ta string Ta Ta
Password to use for VNC authentication.
This type of authentication is known to be cryptographically weak and is not
intended for use on untrusted networks.
.El
.Ss High Definition Audio Settings
.Bl -column "Name" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va play Ta path Ta Ta
Host playback device,
typically
.Pa /dev/dsp0 .
.It Va rec Ta path Ta Ta
Host recording device,
typically
.Pa /dev/dsp0 .
.El
.Ss LPC Device Settings
The LPC bridge stores its configuration under a top-level
.Va lpc
node rather than under the PCI LPC device's node.
The following nodes are available under
.Va lpc :
.Bl -column "pc-testdev" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va bootrom Ta path Ta Ta
Path to a boot ROM.
The contents of this file are copied into the guest's
memory ending just before the 4GB physical address.
If a boot ROM is present, a firmware interface device is
also enabled for use by the boot ROM.
.It Va com1 Ta node Ta Ta
Settings for the COM1 serial port device.
.It Va com2 Ta node Ta Ta
Settings for the COM2 serial port device.
.It Va com3 Ta node Ta Ta
Settings for the COM3 serial port device.
.It Va com4 Ta node Ta Ta
Settings for the COM4 serial port device.
.It Va pc-testdev Ta bool Ta false Ta
Enable the PC debug/test device.
.El
.Ss NVMe Controller Settings
Each NVMe controller supports a single storage device.
The device can be backed either by a memory disk described by the
.Va ram
variable, or a block device using the the block device settings described above.
In addition, each controller supports the following settings:
.Bl -column "ioslots" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va maxq Ta integer Ta 16 Ta
Maximum number of I/O submission and completion queue pairs.
.It Va qsz Ta integer Ta 2058 Ta
Number of elements in each I/O queue.
.It Va ioslots Ta integer Ta 8 Ta
Maximum number of concurrent I/O requests.
.It Va sectsz Ta integer Ta Ta
Sector size.
Can be one of 512, 4096, or 8192.
Devices backed by a memory disk use 4096 as the default.
Devices backed by a block device use the block device's sector size
as the default.
.It Va ser Ta string Ta Ta
Serial number of up to twenty characters.
A default serial number is generated using a hash of the device's PCI address.
.It Va eui64 Ta integer Ta Ta
IEEE Extended Unique Identifier.
If an EUI is not provided, a default is generated using a checksum of the
device's PCI address.
.It Va dsm Ta string Ta auto Ta
Whether or not to advertise DataSet Management support.
One of
.Dq auto ,
.Dq enable ,
or
.Dq disable .
The
.Dq auto
setting only advertises support if the backing store supports
resource freeing, for example via TRIM.
.It Va ram Ta integer Ta Ta
If set, allocate a memory disk as the backing store.
The value of this variable is the size of the memory disk in megabytes.
.El
.Ss PCI Passthrough Settings
.Bl -column "Name" "integer" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va bus Ta integer Ta Ta
Host PCI bus address of device to pass through.
.It Va slot Ta integer Ta Ta
Host PCI slot address of device to pass through.
.It Va func Ta integer Ta Ta
Host PCI function address of device to pass through.
.El
.Ss VirtIO 9p Settings
Each VirtIO 9p device exposes a single filesystem from a host path.
.Bl -column "sharename" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va sharename Ta string Ta Ta
The share name exposed to the guest.
.It Va path Ta path Ta Ta
The path of a directory on the host to export to the guest.
.It Va ro Ta bool Ta false Ta
If true, the guest filesystem is read-only.
.El
.Ss VirtIO Console Device Settings
Each VirtIO Console device contains one or more console ports.
Each port stores its settings in a node named
.Dq port. Ns Va N
under the controller's device node.
The
.Va N
values are formatted as successive decimal values starting with 0.
Each port supports the following settings:
.Bl -column "Name" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va name Ta string Ta Ta
The name of the port exposed to the guest.
.It Va path Ta path Ta Ta
The path of a UNIX domain socket providing the host connection for the port.
.El
.Ss VirtIO Input Interface Settings
Each VirtIO Input device contains one input event device.
All input events of the input event device are send to the guest by VirtIO Input interface.
VirtIO Input Interfaces support the following variables:
.Bl -column "Name" "Format" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va path Ta path Ta Ta
The path of the input event device exposed to the guest
.El
.Ss VirtIO Network Interface Settings
In addition to the network backend settings,
VirtIO network interfaces support the following variables:
.Bl -column "Name" "MAC address" "generated"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va mac Ta MAC address Ta generated Ta
MAC address.
If an explicit address is not provided,
a MAC address is generated from a hash of the device's PCI address.
.It Va mtu Ta integer Ta 1500 Ta
The largest supported MTU advertised to the guest.
.El
.Ss VirtIO SCSI Settings
.Bl -column "Name" "integer" "Default"
.It Sy Name Ta Sy Format Ta Sy Default Ta Sy Description
.It Va dev Ta path Ta Ta
The path of a CAM target layer (CTL) device to export:
.Pa /dev/cam/ctl Ns Oo Ar pp . Ns Ar vp Oc .
.It Va iid Ta integer Ta 0 Ta
Initiator ID to use when sending requests to the CTL port.
.El
.Sh SEE ALSO
.Xr expand_number 3 ,
.Xr getaddrinfo 3 ,
.Xr strtol 3 ,
.Xr netgraph 4 ,
.Xr netmap 4 ,
.Xr ng_socket 4 ,
.Xr tap 4 ,
.Xr vale 4 ,
.Xr vmnet 4 ,
.Xr bhyve 8