BHYVE(8) FreeBSD System Manager's Manual BHYVE(8)
NAME
bhyve - run a guest operating system inside a virtual machine
SYNOPSIS
bhyve [-aCDeHhPSuWwxY]
[-c [[cpus=]numcpus][,sockets=n][,cores=n][,threads=n]] [-f
name,[string|file]=data] [-G [w][bind_address:]port]
[-k config_file] [-K layout] [-l lpcdev[,conf]]
[-m memsize[K|k|M|m|G|g|T|t]] [-o var=value] [-p vcpu:hostcpu]
[-r file] [-s slot,emulation[,conf]] [-U uuid] vmname
bhyve -l help
bhyve -s help
DESCRIPTION
bhyve is a hypervisor that runs guest operating systems inside a virtual
machine. It can run guests on amd64 and arm64 platforms with suitable
hardware support.
Parameters such as the number of virtual CPUs, amount of guest memory,
and I/O connectivity can be specified with command-line parameters.
bhyve is typically used with a boot ROM that can load the guest operating
system. On arm64 platforms, this is currently required. If not using a
boot ROM, the guest operating system must be loaded with bhyveload(8) or
a similar boot loader before running bhyve, otherwise. On amd64, the
edk2-bhyve package provides a UEFI firmware that can be used to boot the
guest; on arm64 the u-boot-bhyve-arm64 package provides a U-Boot image
that can be used to boot the guest.
bhyve runs until the guest operating system reboots or an unhandled
hypervisor exit is detected.
OPTIONS
-a The guest's local APIC is configured in xAPIC mode. This
option only applies to the amd64 platform. xAPIC mode is the
default setting so this option is redundant. It will be
deprecated in a future version.
-C Include guest memory in core files.
-c [[cpus=]numcpus][,sockets=n][,cores=n][,threads=n]
Number of guest virtual CPUs and/or the CPU topology. The
default value for each of numcpus, sockets, cores, and
threads is 1. If numcpus is not specified then it will be
calculated from the other arguments. The topology must be
consistent in that the numcpus must equal the product of
sockets, cores, and threads. If a setting is specified more
than once the last one has precedence.
The maximum number of virtual CPUs defaults to the number of
active physical CPUs in the system available via the
hw.vmm.maxcpu sysctl(8) variable. The limit can be adjusted
via the hw.vmm.maxcpu loader tunable.
-D Destroy the VM on guest initiated power-off.
-e Force bhyve to exit when a guest issues an access to an I/O
port that is not emulated. This is intended for debug
purposes and only applies to the amd64 platform.
-f name,[string|file]=data
Add a fw_cfg file name to the fw_cfg interface. If a string
is specified, the fw_cfg file contains the string as data.
If a file is specified, bhyve reads the file and adds the
file content as fw_cfg data.
-G [w][bind_address:]port
Start a debug server that uses the GDB protocol to export
guest state to a debugger. An IPv4 TCP socket will be bound
to the supplied bind_address and port to listen for debugger
connections. Only a single debugger may be attached to the
debug server at a time. If the option begins with w, bhyve
will pause execution at the first instruction waiting for a
debugger to attach.
-H Yield the virtual CPU thread when a HLT instruction is
detected. If this option is not specified, virtual CPUs will
use 100% of a host CPU. This option applies only to the
amd64 platform.
-h Print help message and exit.
-k config_file
Set configuration variables from a simple, key-value config
file. Each line of the config file is expected to consist of
a config variable name, an equals sign (`='), and a value.
No spaces are permitted between the variable name, equals
sign, or value. Blank lines and lines starting with `#' are
ignored. See bhyve_config(5) for more details.
-K layout Specify the keyboard layout. The value that can be specified
sets the file name in /usr/share/bhyve/kbdlayout. This
specification only works when loaded with UEFI mode for VNC.
When using a VNC client that supports QEMU Extended Key Event
Message (e.g. TigerVNC), this option isn't needed. When
using a VNC client that doesn't support QEMU Extended Key
Event Message (e.g. TightVNC), the layout defaults to the US
keyboard unless specified otherwise.
-l help Print a list of supported LPC devices.
-l lpcdev[,conf]
Allow devices behind the LPC PCI-ISA bridge to be configured.
The only supported devices are the TTY-class devices com1,
com2, com3, and com4, the TPM module tpm, the boot ROM device
bootrom, the fwcfg type and the debug/test device pc-testdev.
The possible values for the conf argument are listed in the
-s flag description.
This option applies only to the amd64 platform. On arm64,
the console and boot ROM devices are configured using the
more generic -o option.
-m memsize[K|k|M|m|G|g|T|t]
Set the guest physical memory size. This must be the same
size that was given to bhyveload(8).
The size argument may be suffixed with one of K, M, G or T
(either upper or lower case) to indicate a multiple of
kilobytes, megabytes, gigabytes, or terabytes. If no suffix
is given, the value is assumed to be in megabytes. The
default is 256M.
-n id,size,cpus[,domain_policy]
Configure guest NUMA domains. This option applies only to
the amd64 platform.
The -n option allows the guest physical address space to be
partitioned into domains. The layout of each domain is
encoded in an ACPI table visible to the guest operating
system. The -n option also allows the specification of a
domainset(9) memory allocation policy for the host memory
backing a given NUMA domain. A guest can have up to 8 NUMA
domains. This feature requires that the guest use a boot
ROM, and in particular cannot be used if the guest was
initialized using bhyveload(8).
Each domain is identified by a numerical id. The domain
memory size is specified using the same format as the -m
flag. The sum of all size parameters overrides the total VM
memory size specified by the -m flag. However, if at least
one domain memory size parameter is missing, the total VM
memory size will be equally distributed across all emulated
domains. The cpuset parameter specifies the set of CPUs that
are part of the domain. The domain_policy parameter may be
optionally used to configure the domainset(9) host NUMA
memory allocation policy for an emulated domain. See the -n
flag in cpuset(1) for a list of valid NUMA memory allocation
policies and their formats.
-o var=value
Set the configuration variable var to value. See
bhyve_config(5) for configuration options.
-P Force the guest virtual CPU to exit when a PAUSE instruction
is detected. This option applies only to the amd64 platform.
-p vcpu:hostcpu
Pin guest's virtual CPU vcpu to hostcpu. Host CPUs and guest
virtual CPUs are numbered starting from 0. A -p option is
required for every guest vCPU to be pinned. To map a 4 vCPU
guest to host CPUs 12-15:
-p 0:12 -p 1:13 -p 2:14 -p 3:15
-r file Resume a guest from a snapshot. The guest memory contents
are restored from file, and the guest device and vCPU state
are restored from the file "file.kern".
Note that the current snapshot file format requires that the
configuration of devices in the new VM match the VM from
which the snapshot was taken by specifying the same -s and -l
options. The count of vCPUs and memory configuration are
read from the snapshot.
-S Wire guest memory.
-s help Print a list of supported PCI devices.
-s slot,emulation[,conf]
Configure a virtual PCI slot and function.
bhyve provides PCI bus emulation and virtual devices that can
be attached to slots on the bus. There are 32 available
slots, with the option of providing up to 8 functions per
slot.
The slot can be specified in one of the following formats:
o pcislot
o pcislot:function
o bus:pcislot:function
The pcislot value is 0 to 31. The optional function value is
0 to 7. The optional bus value is 0 to 255. If not
specified, the function value defaults to 0. If not
specified, the bus value defaults to 0.
See PCI EMULATION for available options for the emulation
argument.
-U uuid Set the universally unique identifier (UUID) in the guest's
System Management BIOS System Information structure. By
default a UUID is generated from the host's hostname and
vmname.
-u RTC keeps UTC time.
-W Force virtio PCI device emulations to use MSI interrupts
instead of MSI-X interrupts.
-w Ignore accesses to unimplemented Model Specific Registers
(MSRs). This is intended for debug purposes.
-x The guest's local APIC is configured in x2APIC mode. This
option applies only to the amd64 platform.
-Y Disable MPtable generation. This option applies only to the
amd64 platform.
vmname Alphanumeric name of the guest. This should be the same as
that created by bhyveload(8).
PCI EMULATION
bhyve provides emulation for various PCI devices. They are specified by
the -s slot,emulation,conf configuration's emulation argument, which can
be one of the following:
hostbridge A simple host bridge. This is usually configured at slot
0, and is required by most guest operating systems.
amd_hostbridge Emulation identical to hostbridge using a PCI vendor ID
of AMD.
passthru PCI pass-through device.
virtio-net Virtio network interface.
virtio-blk Virtio block storage interface.
virtio-scsi Virtio SCSI interface.
virtio-9p Virtio 9p (VirtFS) interface.
virtio-rnd Virtio RNG interface.
virtio-console Virtio console interface, which exposes multiple ports to
the guest in the form of simple char devices for simple
IO between the guest and host userspaces.
virtio-input Virtio input interface.
ahci AHCI controller attached to arbitrary devices.
ahci-cd AHCI controller attached to an ATAPI CD/DVD.
ahci-hd AHCI controller attached to a SATA hard drive.
e1000 Intel e82545 network interface.
uart PCI 16550 serial device.
lpc LPC PCI-ISA bridge with COM1, COM2, COM3, and COM4 16550
serial ports, a boot ROM, and, optionally, a TPM module,
a fw_cfg type, and the debug/test device. The LPC bridge
emulation can only be configured on bus 0.
fbuf Raw framebuffer device attached to VNC server.
xhci eXtensible Host Controller Interface (xHCI) USB
controller.
nvme NVM Express (NVMe) controller.
hda High Definition Audio Controller.
The optional parameter conf describes the backend for device emulations.
If conf is not specified, the device emulation has no backend and can be
considered unconnected.
Network device backends
o tapN[,mac=xx:xx:xx:xx:xx:xx][,mtu=N]
o vmnetN[,mac=xx:xx:xx:xx:xx:xx][,mtu=N]
o ngdN
o netgraph,path=ADDRESS,peerhook=HOOK[,socket=NAME][,hook=HOOK][,mac=xx:xx:xx:xx:xx:xx][,mtu=N]
o slirp[,open][,hostfwd=proto:hostaddr:hostport-guestaddr:guestport][,mac=xx:xx:xx:xx:xx:xx][,mtu=N]
If mac is not specified, the MAC address is derived from a fixed OUI, and
the remaining bytes from an MD5 hash of the slot and function numbers and
the device name. If specified, it must be a unicast MAC address.
The MAC address is an ASCII string in ethers(5) format.
A ngd device can be used to connect a guest to a netgraph(4) through a
ng_device(4) node. This can be used to run bhyve in a VNET(9) jail, and
give it access to the host's netgraph, that cannot be reached directly,
by exposing the ng_device through devfs(8).
With virtio-net devices, the mtu parameter can be specified to inform the
guest about the largest MTU that should be allowed, expressed in bytes.
With netgraph backend, the path and peerhook parameters must be specified
to set the destination node and corresponding hook. The optional
parameters socket and hook may be used to set the ng_socket(4) node name
and source hook. The ADDRESS, HOOK, and NAME must comply with
netgraph(4) addressing rules.
The slirp backend can be used to provide a NATed network to the guest.
This backend has poor performance but does not require any network
configuration on the host system. It depends on the net/libslirp port.
If the open keyword is set, the guest will be able to make outbound
network connections, and bhyve will transparently handle the necessary
address translation. The hostfwd option takes a 5-tuple describing how
connections from the host are to be forwarded to the guest. Multiple
rules can be specified, separated by semicolons. Note that semicolons
must be escaped or quoted to prevent the shell from interpreting them.
The backend will provide DHCP and DNS service to the guest.
Block storage device backends:
o /filename[,block-device-options]
o /dev/xxx[,block-device-options]
The block-device-options are:
nocache Open the file with O_DIRECT.
direct Open the file using O_SYNC.
ro Force the file to be opened read-only.
sectorsize=logical[/physical]
Specify the logical and physical sector sizes of the emulated
disk. The physical sector size is optional and is equal to
the logical sector size if not explicitly specified.
nodelete Disable emulation of guest trim requests via DIOCGDELETE
requests.
bootindex=index
Add the device to the boot order at index. A fw_cfg file is
used to specify the boot order. The guest firmware may
ignore or doesn't support this fw_cfg file. In that case,
this feature doesn't work as expected.
SCSI device backends
o /dev/cam/ctl[pp.vp][,scsi-device-options]
The scsi-device-options are:
iid=IID Initiator ID to use when sending requests to specified CTL
port. The default value is 0.
bootindex=index
Add the device to the boot order at index. A fw_cfg file is
used to specify the boot order. The guest firmware may
ignore or not support this fw_cfg file. In that case, this
feature doesn't work as expected.
9P device backends
o sharename=/path/to/share[,9p-device-options]
The 9p-device-options are:
ro Expose the share in read-only mode.
TTY device backends
stdio Connect the serial port to the standard input and output of
the bhyve process.
/dev/xxx Use the host TTY device for serial port I/O.
tcp=ip:port
Use the TCP server for serial port I/O. Configuring this
option will start a TCP server that waits for connections.
Only one connection is allowed at any time. The TCP server
will immediately close new connections while an existing
connection is active. Note that this feature allows
unprivileged users to access the guest console, so ensure
that access is appropriately restricted.
TPM device backends
o type,path[,tpm-device-options]
Emulate a TPM device. Supported options for type:
passthru Use a physical TPM device. The argument path needs to point
to a valid TPM device path, i.e. /dev/tpm0.
swtpm Connect to a running swtpm instance. The argument path needs
to point to a UNIX domain socket that a swtpm process is
listening on.
The tpm-device-options are:
version=version
Version of the TPM device according to the TCG specification.
Defaults to 2.0, which is the only version currently
supported.
Boot ROM device backends
o romfile[,varfile]
Map romfile in the guest address space reserved for boot firmware.
If varfile is provided, that file is also mapped in the boot firmware
guest address space, and any modifications the guest makes will be saved
to that file.
fw_cfg types:
fwcfg The fw_cfg interface is used to pass information such as the
CPU count or ACPI tables to the guest firmware. Supported
values are `bhyve' and `qemu'. Due to backward compatibility
reasons, `bhyve' is the default option. When `bhyve' is
used, bhyve's fwctl interface is used. It currently reports
only the CPU count to the guest firmware. The `qemu' option
uses QEMU's fw_cfg interface. This interface is widely used
and allows user-defined information to be passed to the
guest. It is used for passing the CPU count, ACPI tables, a
boot order and many other things to the guest. Some
operating systems such as Fedora CoreOS can be configured by
QEMU's fw_cfg interface as well.
Pass-through device backends
o pptN[,passthru-device-options]
o bus/slot/function[,passthru-device-options]
o pcibus:slot:function[,passthru-device-options]
Connect to a PCI device on the host either named ppt N or at the selector
described by slot, bus, and function numbers.
The passthru-device-options are:
rom=romfile
Add romfile as option ROM to the PCI device. The ROM will be
loaded by firmware and should be capable of initializing the
device.
bootindex=index
Add the device to the boot order at index. A fw_cfg file is
used to specify the boot order. The guest firmware may
ignore or doesn't support this fw_cfg file. In that case,
this feature doesn't work as expected.
Guest memory must be wired using the -S option when a pass-through device
is configured.
The host device must have been reserved at boot time using the pptdevs
loader variable as described in vmm(4).
Virtio console device backends
o port1=/path/to/port1.sock[,portN=/path/to/port2.sock ...]
A maximum of 16 ports per device can be created. Every port is named and
corresponds to a Unix domain socket created by bhyve. bhyve accepts at
most one connection per port at a time.
Limitations:
o Due to the lack of destructors in bhyve, sockets on the filesystem
must be cleaned up manually after bhyve exits.
o There is no way to use the "console port" feature, nor the console
port resize at present.
o Emergency write is advertised, but no-op at present.
Virtio input device backends:
o /dev/input/eventX
Send input events of /dev/input/eventX to guest by VirtIO Input
Interface.
Framebuffer device backends
o [rfb=address][,w=width][,h=height][,vga=vgaconf][,wait][,password=password]
Configuration options are defined as follows:
rfb=address (or tcp=address)
A UNIX domain socket or IP address and a port VNC should
listen on. There are three possible formats:
o [IPv4:]port
o [IPv6%zone]:port
o unix:my/unix.sock
The default is to listen on localhost IPv4 address and
default VNC port 5900. An IPv6 address must be enclosed in
square brackets and may contain an optional zone identifier.
w=width and h=height
A display resolution, width and height, respectively. If not
specified, a default resolution of 1024x768 pixels will be
used. Minimal supported resolution is 640x480 pixels, and
maximum is 3840x2160 pixels.
vga=vgaconf
Possible values for this option are io (default), on, and
off. PCI graphics cards have a dual personality in that they
are standard PCI devices with BAR addressing, but may also
implicitly decode legacy VGA I/O space (0x3c0-3df) and memory
space (64 KiB at 0xA0000). The default io option should be
used for guests that attempt to issue BIOS calls which result
in I/O port queries, and fail to boot if I/O decode is
disabled.
The on option should be used along with the CSM BIOS
capability in UEFI to boot traditional BIOS guests that
require the legacy VGA I/O and memory regions to be
available.
The off option should be used for the UEFI guests that assume
that VGA adapter is present if they detect the I/O ports. An
example of such a guest is OpenBSD in UEFI mode.
Please refer to the bhyve FreeBSD wiki page
(https://wiki.freebsd.org/bhyve) for configuration notes of
particular guests.
wait Instruct bhyve to only boot upon the initiation of a VNC
connection, simplifying the installation of operating systems
that require immediate keyboard input. This can be removed
for post-installation use.
password=password
This type of authentication is known to be cryptographically
weak and is not intended for use on untrusted networks. Many
implementations will want to use stronger security, such as
running the session over an encrypted channel provided by
IPsec or SSH.
xHCI USB device backends
o tablet
A USB tablet device that provides precise cursor synchronization when
using VNC.
NVMe device backends
o devpath[,maxq=#][,qsz=#][,ioslots=#][,sectsz=#][,ser=#][,eui64=#][,dsm=opt]
Configuration options are defined as follows:
devpath Accepted device paths are: /dev/blockdev or /path/to/image or
ram=size_in_MiB.
maxq Max number of queues.
qsz Max elements in each queue.
ioslots Max number of concurrent I/O requests.
sectsz Sector size (defaults to blockif sector size).
ser Serial number with maximum 20 characters.
eui64 IEEE Extended Unique Identifier (8 byte value).
dsm Dataset Management support. Supported values are: auto,
enable, and disable.
AHCI device backends
o [[hd:|cd:]path][,nmrr=nmrr][,ser=#][,rev=#][,model=#]
Configuration options are defined as follows:
nmrr Nominal Media Rotation Rate, known as RPM. A value of 1
indicates that the device is a solid state drive, i.e., non-
rotational. Default value is 0.
ser Serial number with maximum 20 characters.
rev Revision number with maximum 8 characters.
model Model number with maximum 40 characters.
HD Audio device backends
o [play=playback][,rec=recording]
Configuration options are defined as follows:
play Playback device, typically /dev/dsp0.
rec Recording device, typically /dev/dsp0.
CONFIGURATION VARIABLES
bhyve uses an internal tree of configuration variables to describe global
and per-device settings. When bhyve starts, it parses command line
options (including config files) in the order given on the command line.
Each command line option sets one or more configuration variables. For
example, the -s option creates a new tree node for a PCI device and sets
one or more variables under that node including the device model and
device model-specific variables. Variables may be set multiple times
during this parsing stage with the final value overriding previous
values.
Once all of the command line options have been processed, the
configuration values are frozen. bhyve then uses the value of
configuration values to initialize device models and global settings.
More details on configuration variables can be found in bhyve_config(5).
CONFIGURATION FILE CREATION
The -k flag allows one to provide a path to a configuration file holding
all settings, which otherwise would need to be defined by providing a
long list of program arguments to bhyve.
There is a very simple way to translate a complex set of program
arguments to an equivalent configuration file in bhyve_config(5) format.
Use -o config.dump=1 to make bhyve dump a configuration file representing
the used flags and arguments to stdout. You can pipe the output into a
file to persist the generated settings.
Make sure to remove the config.dump line from the resulting configuration
file before using it to start bhyve.
DEBUG SERVER
The current debug server provides limited support for debuggers.
Registers
Each virtual CPU is exposed to the debugger as a thread.
General purpose registers can be queried for each virtual CPU, but other
registers such as floating-point and system registers cannot be queried.
Memory
Memory (including memory mapped I/O regions) can be read and written by
the debugger. Memory operations use virtual addresses that are resolved
to physical addresses via the current virtual CPU's active address
translation.
Control
The running guest can be interrupted by the debugger at any time (for
example, by pressing Ctrl-C in the debugger).
Single stepping is only supported on Intel CPUs supporting the MTRAP VM
exit.
Breakpoints are supported on Intel CPUs that support single stepping.
Note that continuing from a breakpoint while interrupts are enabled in
the guest may not work as expected due to timer interrupts firing while
single stepping over the breakpoint.
SIGNAL HANDLING
bhyve deals with the following signals:
SIGTERM Trigger ACPI poweroff for a VM
EXIT STATUS
Exit status indicates how the VM was terminated:
0 rebooted
1 powered off
2 halted
3 triple fault (amd64 only)
4 exited due to an error
5 suspended
EXAMPLES
If not using a boot ROM, the guest operating system must have been loaded
with bhyveload(8) or a similar boot loader before bhyve(4) can be run.
Otherwise, the boot loader is not needed.
To run a virtual machine with 1 GiB of memory, two virtual CPUs, a virtio
block device backed by the /my/image filesystem image, and a serial port
for the console:
bhyve -c 2 -s 0,hostbridge -s 1,lpc -s 2,virtio-blk,/my/image \
-l com1,stdio -H -P -m 1G vm1
To do the same on arm64:
bhyve -c 2 -s 0,hostbridge -s 1,virtio-blk,/my/image -o console=stdio \
-o bootrom=/usr/local/share/u-boot/u-boot-bhyve-arm64/u-boot.bin -m 1G vm1
Run a 24 GiB single-CPU virtual machine with three network ports, one of
which has a MAC address specified:
bhyve -s 0,hostbridge -s 1,lpc -s 2:0,virtio-net,tap0 \
-s 2:1,virtio-net,tap1 \
-s 2:2,virtio-net,tap2,mac=00:be:fa:76:45:00 \
-s 3,virtio-blk,/my/image -l com1,stdio \
-H -P -m 24G bigvm
Run an 8 GiB quad-CPU virtual machine with 8 AHCI SATA disks, an AHCI
ATAPI CD-ROM, a single virtio network port, an AMD hostbridge, and the
console port connected to an nmdm(4) null-modem device.
bhyve -c 4 \
-s 0,amd_hostbridge -s 1,lpc \
-s 1:0,ahci,hd:/images/disk.1,hd:/images/disk.2,\
hd:/images/disk.3,hd:/images/disk.4,\
hd:/images/disk.5,hd:/images/disk.6,\
hd:/images/disk.7,hd:/images/disk.8,\
cd:/images/install.iso \
-s 3,virtio-net,tap0 \
-l com1,/dev/nmdm0A \
-H -P -m 8G
Run a UEFI virtual machine with a display resolution of 800 by 600 pixels
that can be accessed via VNC at: 0.0.0.0:5900 or via serial console over
TCP at: 127.0.0.1:1234 (unsafe if you expose serial console without
protection).
bhyve -c 2 -m 4G -w -H \
-s 0,hostbridge \
-s 3,ahci-cd,/path/to/uefi-OS-install.iso \
-s 4,ahci-hd,disk.img \
-s 5,virtio-net,tap0 \
-s 29,fbuf,tcp=0.0.0.0:5900,w=800,h=600,wait \
-s 30,xhci,tablet \
-s 31,lpc -l com1,tcp=127.0.0.1:1234 \
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \
uefivm
Run a UEFI virtual machine with a VNC display that is bound to all IPv6
addresses on port 5900 and a serial I/O port bound to TCP port 1234 of
loopback address (unsafe if you expose serial console without
protection).
bhyve -c 2 -m 4G -w -H \
-s 0,hostbridge \
-s 4,ahci-hd,disk.img \
-s 5,virtio-net,tap0 \
-s 29,fbuf,tcp=[::]:5900,w=800,h=600 \
-s 30,xhci,tablet \
-s 31,lpc -l com1,tcp=[::1]:1234 \
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \
uefivm
Run a UEFI virtual machine with a VARS file to save EFI variables. Note
that bhyve will write guest modifications to the given VARS file. Be
sure to create a per-guest copy of the template VARS file from /usr.
bhyve -c 2 -m 4g -w -H \
-s 0,hostbridge \
-s 31,lpc -l com1,stdio \
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI_CODE.fd,BHYVE_UEFI_VARS.fd
uefivm
To create a configuration file configfile for a virtual machine, use -o
config.dump=1:
/usr/sbin/bhyve -c 2 -m 256 -H -P \
-s 0:0,hostbridge -s 1:0,virtio-net,tap0 \
-s 2:0,ahci-hd,./vm0.img \
-s 31,lpc -l com1,stdio \
-o config.dump=1 vm0 > configfile
Then use an editor of your choice to remove the line "config.dump=1" from
the newly generated configfile.
To start bhyve using this configuration file, use flag -k:
/usr/sbin/bhyve -k configfile vm0
Run a UEFI virtual machine with four CPUs and two emulated NUMA domains:
bhyve -c 4 -w -H \
-s 0,hostbridge \
-s 4,ahci-hd,disk.img \
-s 31,lpc -l com1,stdio \
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \
-n id=0,size=4G,cpus=0-1 \
-n id=1,size=4G,cpus=2-3 \
numavm
Assuming a host machine with two NUMA domains, run a UEFI virtual machine
with four CPUs using a prefer domainset(9) policy to allocate guest
memory from the first host NUMA domain only.
bhyve -c 2 -w -H \
-s 0,hostbridge \
-s 4,ahci-hd,disk.img \
-s 31,lpc -l com1,stdio \
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \
-n id=0,size=4G,cpus=0-1,domain_policy=prefer:0 \
numavm
SEE ALSO
bhyve(4), netgraph(4), ng_socket(4), nmdm(4), vmm(4), bhyve_config(5),
ethers(5), bhyvectl(8), bhyveload(8), domainset(9)
Intel, 64 and IA-32 Architectures Software Developer's Manual, Volume 3.
HISTORY
bhyve first appeared in FreeBSD 10.0.
AUTHORS
Neel Natu <neel@freebsd.org>
Peter Grehan <grehan@freebsd.org>
FreeBSD 15.1-STABLE-HBSD May 15, 2026 BHYVE(8)