.\" Copyright (c) 2013 Peter Grehan .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD$ .\" .Dd August 19, 2021 .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 .Op Fl G Ar port .Op Fl k Ar file .Oo Fl l .Sm off .Ar lpcdev Op Cm \&, Ar conf .Sm on .Oc .Oo Fl m .Sm off .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. Required for .Fx Ns /amd64 guests. .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. The current maximum number of guest virtual CPUs is 16. 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. .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 G Xo .Sm off .Oo Ar w Oc .Oo Ar bind_address: 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 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 .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. .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 boot ROM device .Cm bootrom , 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 . .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, 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 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. .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. .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 Boot ROM device backends: .Bl -tag -width 10n .It Ar romfile Map .Ar romfile in the guest address space reserved for boot firmware. .El .Pp Pass-through device backends: .Bl -tag -width 10n .It Ns Ar slot Ns Cm \&/ Ns Ar bus Ns Cm \&/ Ns Ar function Connect to a PCI device on the host at the selector described by .Ar slot , .Ar bus , and .Ar function numbers. .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 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 .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