usr.sbin/bhyve/bhyve.8

.\" Copyright (c) 2013 Peter Grehan
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.Dd October 12, 2023
.Dt BHYVE 8
.Os
.Sh NAME
.Nm bhyve
.Nd "run a guest operating system inside a virtual machine"
.Sh SYNOPSIS
.Nm
.Op Fl AaCDeHhPSuWwxY
.Oo
.Sm off
.Fl c\~
.Oo
.Op Cm cpus=
.Ar numcpus
.Oc
.Op Cm ,sockets= Ar n
.Op Cm ,cores= Ar n
.Op Cm ,threads= Ar n
.Oc
.Sm on
.Oo Fl f
.Sm off
.Ar name Cm \&,
.Oo
.Cm string No | Cm file
.Oc
.Cm \&= Ar data
.Sm on
.Oc
.Oo
.Sm off
.Fl G\~
.Oo Ar w Oc
.Oo Ar bind_address Cm \&: Oc
.Ar port
.Sm on
.Oc
.Op Fl k Ar config_file
.Op Fl K Ar layout
.Oo Fl l
.Sm off
.Ar lpcdev Op Cm \&, Ar conf
.Sm on
.Oc
.Sm off
.Oo Fl m\~
.Ar memsize
.Oo
.Cm K | Cm k | Cm M | Cm m | Cm G | Cm g | Cm T | Cm t
.Oc
.Sm on
.Oc
.Op Fl o Ar var Ns Cm = Ns Ar value
.Op Fl p Ar vcpu Ns Cm \&: Ns Ar hostcpu
.Op Fl r Ar file
.Sm off
.Oo Fl s\~
.Ar slot Cm \&, Ar emulation Op Cm \&, Ar conf
.Sm on
.Oc
.Op Fl U Ar uuid
.Ar vmname
.Nm
.Fl l Cm help
.Nm
.Fl s Cm help
.Sh DESCRIPTION
.Nm
is a hypervisor that runs guest operating systems inside a
virtual machine.
.Pp
Parameters such as the number of virtual CPUs, amount of guest memory, and
I/O connectivity can be specified with command-line parameters.
.Pp
If not using a boot ROM, the guest operating system must be loaded with
.Xr bhyveload 8
or a similar boot loader before running
.Nm ,
otherwise, it is enough to run
.Nm
with a boot ROM of choice.
.Pp
.Nm
runs until the guest operating system reboots or an unhandled hypervisor
exit is detected.
.Sh OPTIONS
.Bl -tag -width 10n
.It Fl A
Generate ACPI tables.
bhyve always generates ACPI tables so this option is obsolete.
.It Fl a
The guest's local APIC is configured in xAPIC mode.
The xAPIC mode is the default setting so this option is redundant.
It will be deprecated in a future version.
.It Fl C
Include guest memory in core file.
.It Fl c Op Ar setting ...
Number of guest virtual CPUs
and/or the CPU topology.
The default value for each of
.Ar numcpus ,
.Ar sockets ,
.Ar cores ,
and
.Ar threads
is 1.
If
.Ar numcpus
is not specified then it will be calculated from the other arguments.
The topology must be consistent in that the
.Ar numcpus
must equal the product of
.Ar sockets ,
.Ar cores ,
and
.Ar threads .
If a
.Ar setting
is specified more than once the last one has precedence.
.Pp
The maximum number of virtual CPUs defaults to the number of active
physical CPUs in the system available via the
.Va hw.vmm.maxcpu
.Xr sysctl 8
variable.
The limit can be adjusted via the
.Va hw.vmm.maxcpu
loader tunable.
.It Fl D
Destroy the VM on guest initiated power-off.
.It Fl e
Force
.Nm
to exit when a guest issues an access to an I/O port that is not emulated.
This is intended for debug purposes.
.It Fl f Ar name Ns Cm \&, Ns Oo Cm string Ns No | Ns Cm file Ns Oc Ns Cm \&= Ns Ar data
Add a fw_cfg file
.Ar name
to the fw_cfg interface.
If a
.Cm string
is specified, the fw_cfg file contains the string as data.
If a
.Cm file
is specified, bhyve reads the file and adds the file content as fw_cfg data.
.It Fl G Xo
.Sm off
.Oo Ar w Oc
.Oo Ar bind_address Cm \&: Oc
.Ar port
.Sm on
.Xc
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
.Ar bind_address
and
.Ar 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
.Sq w ,
.Nm
will pause execution at the first instruction waiting for a debugger to attach.
.It Fl 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.
.It Fl h
Print help message and exit.
.It Fl k Ar 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
.It Fl K Ar layout
Specify the keyboard layout.
The value that can be specified sets the file name in
.Ar /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.
.Pq Sq = ,
and a value.
No spaces are permitted between the variable name, equals sign, or
value.
Blank lines and lines starting with
.Sq #
are ignored.
See
.Xr bhyve_config 5
for more details.
.It Fl l Cm help
Print a list of supported LPC devices.
.It Fl l Ar lpcdev Ns Op Cm \&, Ns Ar conf
Allow devices behind the LPC PCI-ISA bridge to be configured.
The only supported devices are the TTY-class devices
.Cm com1 , com2 , com3 ,
and
.Cm com4 ,
the TPM module
.Cm tpm ,
the boot ROM device
.Cm bootrom ,
the
.Cm fwcfg
type and the debug/test device
.Cm pc-testdev .
.Pp
The possible values for the
.Ar conf
argument are listed in the
.Fl s
flag description.
.It Xo
.Fl m Ar memsize Ns Oo
.Sm off
.Cm K | k | M | m | G | g | T | t
.Sm on
.Oc
.Xc
Set the guest physical memory size
This must be the same size that was given to
.Xr bhyveload 8 .
.Pp
The size argument may be suffixed with one of
.Cm K , M , G
or
.Cm 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.
.Pp
The default is 256M.
.It Fl o Ar var Ns Cm = Ns Ar value
Set the configuration variable
.Ar var
to
.Ar value .
.It Fl P
Force the guest virtual CPU to exit when a PAUSE instruction is detected.
.It Fl p Ar vcpu Ns Cm \& : Ns Ar hostcpu
Pin guest's virtual CPU
.Em vcpu
to
.Em hostcpu .
Host CPUs and guest virtual CPUs are numbered starting from 0.
A
.Fl p
option is required for every guest vCPU to be pinned.
To map a 4 vCPU guest to host CPUs 12-15:
.Bd -literal
-p 0:12 -p 1:13 -p 2:14 -p 3:15
.Ed
.It Fl r Ar file
Resume a guest from a snapshot.
The guest memory contents are restored from
.Ar file ,
and the guest device and vCPU state are restored from the file
.Dq Ar file Ns .kern .
.Pp
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
.Fl s
and
.Fl l
options.
The count of vCPUs and memory configuration are read from the snapshot.
.It Fl S
Wire guest memory.
.It Fl s Cm help
Print a list of supported PCI devices.
.It Fl s Ar slot Ns Cm \&, Ns Ar emulation Ns Op Cm \&, Ns Ar conf
Configure a virtual PCI slot and function.
.Pp
.Nm
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.
.Pp
The
.Ar slot
can be specified in one of the following formats:
.Pp
.Bl -bullet -compact
.It
.Ar pcislot
.It
.Sm off
.Ar pcislot Cm \&: Ar function
.Sm on
.It
.Sm off
.Ar bus Cm \&: Ar pcislot Cm \&: Ar function
.Sm on
.El
.Pp
The
.Ar pcislot
value is 0 to 31.
The optional
.Ar function
value is 0 to 7.
The optional
.Ar bus
value is 0 to 255.
If not specified, the
.Ar function
value defaults to 0.
If not specified, the
.Ar bus
value defaults to 0.
.Pp
The
.Ar emulation
argument
can be one of the following:
.Bl -tag -width "amd_hostbridge"
.It Cm hostbridge
A simple host bridge.
This is usually configured at slot 0, and is required by most guest
operating systems.
.It Cm amd_hostbridge
Emulation identical to
.Cm hostbridge
using a PCI vendor ID of AMD.
.It Cm passthru
PCI pass-through device.
.It Cm virtio-net
Virtio network interface.
.It Cm virtio-blk
Virtio block storage interface.
.It Cm virtio-scsi
Virtio SCSI interface.
.It Cm virtio-9p
Virtio 9p (VirtFS) interface.
.It Cm virtio-rnd
Virtio RNG interface.
.It Cm 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.
.It Cm virtio-input
Virtio input interface.
.It Cm ahci
AHCI controller attached to arbitrary devices.
.It Cm ahci-cd
AHCI controller attached to an ATAPI CD/DVD.
.It Cm ahci-hd
AHCI controller attached to a SATA hard drive.
.It Cm e1000
Intel e82545 network interface.
.It Cm uart
PCI 16550 serial device.
.It Cm lpc
LPC PCI-ISA bridge with COM1, COM2, COM3, and COM4 16550 serial ports,
a boot ROM, and,
optionally, a fwcfg type and the debug/test device.
The LPC bridge emulation can only be configured on bus 0.
.It Cm fbuf
Raw framebuffer device attached to VNC server.
.It Cm xhci
eXtensible Host Controller Interface (xHCI) USB controller.
.It Cm nvme
NVM Express (NVMe) controller.
.It Cm hda
High Definition Audio Controller.
.El
.Pp
The optional parameter
.Ar conf
describes the backend for device emulations.
If
.Ar conf
is not specified, the device emulation has no backend and can be
considered unconnected.
.Pp
Network device backends:
.Sm off
.Bl -bullet
.It
.Xo
.Cm tap Ar N
.Op Cm \&,mac= Ar xx:xx:xx:xx:xx:xx
.Op Cm \&,mtu= Ar N
.Xc
.It
.Xo
.Cm vmnet Ar N
.Op Cm \&,mac= Ar xx:xx:xx:xx:xx:xx
.Op Cm \&,mtu= Ar N
.Xc
.It
.Xo
.Cm netgraph,path= Ar ADDRESS Cm \&,peerhook= Ar HOOK
.Op Cm \&,socket= Ar NAME
.Op Cm \&,hook= Ar HOOK
.Op Cm \&,mac= Ar xx:xx:xx:xx:xx:xx
.Op Cm \&,mtu= Ar N
.Xc
.El
.Sm on
.Pp
If
.Cm 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.
.Pp
The MAC address is an ASCII string in
.Xr ethers 5
format.
.Pp
With
.Cm virtio-net
devices, the
.Cm mtu
parameter can be specified to inform the guest about the largest MTU
that should be allowed, expressed in bytes.
.Pp
With
.Cm netgraph
backend, the
.Cm path
and
.Cm peerhook
parameters must be specified to set the destination node and corresponding hook.
The optional parameters
.Cm socket
and
.Cm hook
may be used to set the
.Xr ng_socket 4
node name and source hook.
The
.Ar ADDRESS ,
.Ar HOOK ,
and
.Ar NAME
must comply with
.Xr netgraph 4
addressing rules.
.Pp
Block storage device backends:
.Sm off
.Bl -bullet
.It
.Ar /filename Op Cm \&, Ar block-device-options
.It
.Ar /dev/xxx Op Cm \&, Ar block-device-options
.El
.Sm on
.Pp
The
.Ar block-device-options
are:
.Bl -tag -width 10n
.It Cm nocache
Open the file with
.Dv O_DIRECT .
.It Cm direct
Open the file using
.Dv O_SYNC .
.It Cm ro
Force the file to be opened read-only.
.It Cm sectorsize= Ns Ar logical Ns Oo Cm \&/ Ns Ar physical Oc
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.
.It Cm nodelete
Disable emulation of guest trim requests via
.Dv DIOCGDELETE
requests.
.It Li bootindex= Ns Ar index
Add the device to the bootorder at
.Ar index .
A fwcfg file is used to specify the bootorder.
The guest firmware may ignore or doesn't support this fwcfg file.
In that case, this feature doesn't work as expected.
.El
.Pp
SCSI device backends:
.Sm off
.Bl -bullet
.It
.Pa /dev/cam/ctl Oo Ar pp Cm \&. Ar vp Oc Oo Cm \&, Ar scsi-device-options Oc
.El
.Sm on
.Pp
The
.Ar scsi-device-options
are:
.Bl -tag -width 10n
.It Cm iid= Ns Ar IID
Initiator ID to use when sending requests to specified CTL port.
The default value is 0.
.It Li bootindex= Ns Ar index
Add the device to the bootorder at
.Ar index .
A fwcfg file is used to specify the bootorder.
The guest firmware may ignore or doesn't support this fwcfg file.
In that case, this feature doesn't work as expected.
.El
.Pp
9P device backends:
.Sm off
.Bl -bullet
.It
.Ar sharename Cm = Ar /path/to/share Op Cm \&, Ar 9p-device-options
.El
.Sm on
.Pp
The
.Ar 9p-device-options
are:
.Bl -tag -width 10n
.It Cm ro
Expose the share in read-only mode.
.El
.Pp
TTY device backends:
.Bl -tag -width 10n
.It Cm stdio
Connect the serial port to the standard input and output of
the
.Nm
process.
.It Ar /dev/xxx
Use the host TTY device for serial port I/O.
.El
.Pp
TPM device backends:
.Bl -tag -width 10n
.It Ar type Ns \&, Ns Ar path Ns Op Cm \&, Ns Ar tpm-device-options
Emulate a TPM device.
.El
.Pp
The
.Ar tpm-device-options
are:
.Bl -tag -width 10n
.It Cm version= Ns Ar version
Version of the TPM device according to the TCG specification.
Defaults to
.Cm 2.0
.El
.El
.Pp
Boot ROM device backends:
.Bl -tag -width 10n
.It Ar romfile Ns Op Cm \&, Ns Ar varfile
Map
.Ar romfile
in the guest address space reserved for boot firmware.
If
.Ar 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.
.El
.Pp
Fwcfg types:
.Bl -tag -width 10n
.It Ar fwcfg
The fwcfg interface is used to pass information such as the CPU count
or ACPI tables to the guest firmware.
Supported values are
.Ql bhyve
and
.Ql qemu .
Due to backward compatibility reasons,
.Ql bhyve
is the default option.
When
.Ql bhyve
is used, bhyve's fwctl interface is used.
It currently reports only the CPU count to the guest firmware.
The
.Ql qemu
option uses QEMU's fwcfg 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 fwcfg interface as well.
.El
.Pp
Pass-through device backends:
.Sm off
.Bl -bullet
.It
.Cm ppt Ar N Oo , Ar passthru-device-options Oc
.It
.Ns Ar bus Cm \&/ Ar slot Cm \&/ Ar function
.Op , Ar passthru-device-options
.It
.Cm pci Ar bus Cm : Ar slot Cm : Ns Ar function
.Op , Ar passthru-device-options
.El
.Sm on
.Pp
Connect to a PCI device on the host either named ppt
.Ns Ar N
or at the selector described by
.Ar slot ,
.Ar bus ,
and
.Ar function
numbers.
.Pp
The
.Ar passthru-device-options
are:
.Bl -tag -width 10n
.It Cm rom= Ns Ar romfile
Add
.Ar romfile
as option ROM to the PCI device.
The ROM will be loaded by firmware and should be capable of
initializing the device.
.It Li bootindex= Ns Ar index
Add the device to the bootorder at
.Ar index .
A fwcfg file is used to specify the bootorder.
The guest firmware may ignore or doesn't support this fwcfg file.
In that case, this feature doesn't work as expected.
.El
.Pp
Guest memory must be wired using the
.Fl S
option when a pass-through device is configured.
.Pp
The host device must have been reserved at boot-time using the
.Va pptdevs
loader variable as described in
.Xr vmm 4 .
.Pp
TPM devices:
.Bl -tag -width 10n
.It Ns Ar type
Specifies the type of the TPM device.
.Pp
Supported types:
.Bl -tag -width 10n
.It Cm passthru
.El
.It Cm version= Ns Ar version
The
.Ar version
of the emulated TPM device according to the TCG specification.
.Pp
Supported versions:
.Bl -tag -width 10n
.It Cm 2.0
.El
.El
.Pp
Virtio console device backends:
.Bl -bullet
.Sm off
.It
.Cm port1= Ns Ar /path/to/port1.sock Ns Op Cm ,port Ns Ar N Cm \&= Ns Ar /path/to/port2.sock No \~ Ar ...
.Sm on
.El
.Pp
A maximum of 16 ports per device can be created.
Every port is named and corresponds to a Unix domain socket created by
.Nm .
.Nm
accepts at most one connection per port at a time.
.Pp
Limitations:
.Bl -bullet
.It
Due to lack of destructors in
.Nm ,
sockets on the filesystem must be cleaned up manually after
.Nm
exits.
.It
There is no way to use the
.Dq console port
feature, nor the console port
resize at present.
.It
Emergency write is advertised, but no-op at present.
.El
.Pp
Virtio input device backends:
.Bl -tag -width 10n
.It Ar /dev/input/eventX
Send input events of
.Ar /dev/input/eventX
to guest by VirtIO Input Interface.
.El
.Pp
Framebuffer devices backends:
.Bl -bullet
.Sm off
.It
.Op Cm rfb= Ar ip-and-port
.Op Cm ,w= Ar width
.Op Cm ,h= Ar height
.Op Cm ,vga= Ar vgaconf
.Op Cm ,wait
.Op Cm ,password= Ar password
.Sm on
.El
.Pp
Configuration options are defined as follows:
.Bl -tag -width 10n
.It Cm rfb= Ns Ar ip-and-port Pq or Cm tcp= Ns Ar ip-and-port
An IP address and a port VNC should listen on.
There are two formats:
.Pp
.Bl -bullet -compact
.It
.Sm off
.Op Ar IPv4 Cm \&:
.Ar port
.Sm on
.It
.Sm off
.Cm \&[ Ar IPv6%zone Cm \&] Cm \&: Ar port
.Sm on
.El
.Pp
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.
.It Cm w= Ns Ar width No and Cm h= Ns Ar 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 1920x1200 pixels.
.It Cm vga= Ns Ar vgaconf
Possible values for this option are
.Cm io
(default),
.Cm on
, and
.Cm 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
.Pq Ad 0x3c0-3df
and memory space
.Pq 64KB at Ad 0xA0000 .
The default
.Cm 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.
.Pp
The
.Cm 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.
.Pp
The
.Cm 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
.Ox
in UEFI mode.
.Pp
Please refer to the
.Nm
.Fx
wiki page
.Pq Lk https://wiki.freebsd.org/bhyve
for configuration notes of particular guests.
.It Cm wait
Instruct
.Nm
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.
.It Cm password= Ns Ar 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.
.El
.Pp
xHCI USB device backends:
.Bl -tag -width 10n
.It Cm tablet
A USB tablet device which provides precise cursor synchronization
when using VNC.
.El
.Pp
NVMe device backends:
.Bl -bullet
.Sm off
.It
.Ar devpath
.Op Cm ,maxq= Ar #
.Op Cm ,qsz= Ar #
.Op Cm ,ioslots= Ar #
.Op Cm ,sectsz= Ar #
.Op Cm ,ser= Ar #
.Op Cm ,eui64= Ar #
.Op Cm ,dsm= Ar opt
.Sm on
.El
.Pp
Configuration options are defined as follows:
.Bl -tag -width 10n
.It Ar devpath
Accepted device paths are:
.Ar /dev/blockdev
or
.Ar /path/to/image
or
.Cm ram= Ns Ar size_in_MiB .
.It Cm maxq
Max number of queues.
.It Cm qsz
Max elements in each queue.
.It Cm ioslots
Max number of concurrent I/O requests.
.It Cm sectsz
Sector size (defaults to blockif sector size).
.It Cm ser
Serial number with maximum 20 characters.
.It Cm eui64
IEEE Extended Unique Identifier (8 byte value).
.It Cm dsm
DataSet Management support.
Supported values are:
.Cm auto , enable ,
and
.Cm disable .
.El
.Pp
AHCI device backends:
.Bl -bullet
.It
.Sm off
.Op Oo Cm hd\&: | cd\&: Oc Ar path
.Op Cm ,nmrr= Ar nmrr
.Op Cm ,ser= Ar #
.Op Cm ,rev= Ar #
.Op Cm ,model= Ar #
.Sm on
.El
.Pp
Configuration options are defined as follows:
.Bl -tag -width 10n
.It Cm nmrr
Nominal Media Rotation Rate, known as RPM.
Value 1 will indicate device as Solid State Disk.
Default value is 0, not report.
.It Cm ser
Serial Number with maximum 20 characters.
.It Cm rev
Revision Number with maximum 8 characters.
.It Cm model
Model Number with maximum 40 characters.
.El
.Pp
HD Audio device backends:
.Bl -bullet
.It
.Sm off
.Op Cm play= Ar playback
.Op Cm ,rec= Ar recording
.Sm on
.El
.Pp
Configuration options are defined as follows:
.Bl -tag -width 10n
.It Cm play
Playback device, typically
.Ar /dev/dsp0 .
.It Cm rec
Recording device, typically
.Ar /dev/dsp0 .
.El
.It Fl U Ar uuid
Set the universally unique identifier
.Pq UUID
in the guest's System Management BIOS System Information structure.
By default a UUID is generated from the host's hostname and
.Ar vmname .
.It Fl u
RTC keeps UTC time.
.It Fl W
Force virtio PCI device emulations to use MSI interrupts instead of MSI-X
interrupts.
.It Fl w
Ignore accesses to unimplemented Model Specific Registers (MSRs).
This is intended for debug purposes.
.It Fl x
The guest's local APIC is configured in x2APIC mode.
.It Fl Y
Disable MPtable generation.
.It Ar vmname
Alphanumeric name of the guest.
This should be the same as that created by
.Xr bhyveload 8 .
.El
.Sh CONFIGURATION VARIABLES
.Nm
uses an internal tree of configuration variables to describe global and
per-device settings.
When
.Nm
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
.Fl 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.
.Pp
Once all of the command line options have been processed,
the configuration values are frozen.
.Nm
then uses the value of configuration values to initialize device models
and global settings.
.Pp
More details on configuration variables can be found in
.Xr bhyve_config 5 .
.Sh DEBUG SERVER
The current debug server provides limited support for debuggers.
.Ss Registers
Each virtual CPU is exposed to the debugger as a thread.
.Pp
General purpose registers can be queried for each virtual CPU, but other
registers such as floating-point and system registers cannot be queried.
.Ss 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.
.Ss Control
The running guest can be interrupted by the debugger at any time
.Pq for example, by pressing Ctrl-C in the debugger .
.Pp
Single stepping is only supported on Intel CPUs supporting the MTRAP VM exit.
.Pp
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.
.Sh SIGNAL HANDLING
.Nm
deals with the following signals:
.Pp
.Bl -tag -width SIGTERM -compact
.It SIGTERM
Trigger ACPI poweroff for a VM
.El
.Sh EXIT STATUS
Exit status indicates how the VM was terminated:
.Pp
.Bl -tag -width indent -compact
.It 0
rebooted
.It 1
powered off
.It 2
halted
.It 3
triple fault
.It 4
exited due to an error
.El
.Sh EXAMPLES
If not using a boot ROM, the guest operating system must have been loaded with
.Xr bhyveload 8
or a similar boot loader before
.Xr bhyve 4
can be run.
Otherwise, the boot loader is not needed.
.Pp
To run a virtual machine with 1GB of memory, two virtual CPUs, a virtio
block device backed by the
.Pa /my/image
filesystem image, and a serial port for the console:
.Bd -literal -offset indent
bhyve -c 2 -s 0,hostbridge -s 1,lpc -s 2,virtio-blk,/my/image \\
  -l com1,stdio -A -H -P -m 1G vm1
.Ed
.Pp
Run a 24GB single-CPU virtual machine with three network ports, one of which
has a MAC address specified:
.Bd -literal -offset indent
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 \\
  -A -H -P -m 24G bigvm
.Ed
.Pp
Run an 8GB 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
.Xr nmdm 4
null-modem device.
.Bd -literal -offset indent
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 \\
  -A -H -P -m 8G
.Ed
.Pp
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.
.Bd -literal -offset indent
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,stdio \\
  -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \\
   uefivm
.Ed
.Pp
Run a UEFI virtual machine with a VNC display that is bound to all IPv6
addresses on port 5900.
.Bd -literal -offset indent
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,stdio \\
  -l bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd \\
   uefivm
.Ed
.Pp
Run a UEFI virtual machine with a VARS file to save EFI variables.
Note that
.Nm
will write guest modifications to the given VARS file.
Be sure to create a per-guest copy of the template VARS file from
.Pa /usr .
.Bd -literal -offset indent
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
.Ed
.Sh SEE ALSO
.Xr bhyve 4 ,
.Xr netgraph 4 ,
.Xr ng_socket 4 ,
.Xr nmdm 4 ,
.Xr vmm 4 ,
.Xr bhyve_config 5 ,
.Xr ethers 5 ,
.Xr bhyvectl 8 ,
.Xr bhyveload 8
.Pp
.Rs
.%A Intel
.%B 64 and IA-32 Architectures Software Developer’s Manual
.%V Volume 3
.Re
.Sh HISTORY
.Nm
first appeared in
.Fx 10.0 .
.Sh AUTHORS
.An Neel Natu Aq Mt neel@freebsd.org
.An Peter Grehan Aq Mt grehan@freebsd.org