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VMM(4)			     Kernel Interfaces Manual			  VMM(4)

NAME
     vmm.ko -- bhyve virtual machine monitor

SYNOPSIS
     To load the driver as a module at boot, add this line to loader.conf(5):

	   vmm_load="YES"

     The module can also be loaded manually with kldload(8):

	   kldload vmm

DESCRIPTION
     vmm.ko provides the kernel portion of the bhyve(4) hypervisor.  The follow-
     ing platforms are supported:

     *	 amd64:  An  Intel  CPU with VT-x/EPT or AMD CPU with SVM support is re-
	 quired.

     *	 arm64: The boot CPU must start in EL2 and the system must have a  GICv3
	 interrupt controller.	VHE support will be used if available.

     *	 riscv: The CPUs must implement the H (hypervisor) RISC-V ISA extension.

     PCI  device  passthrough  to  a virtual machine requires hardware with VT-d
     support and is available only on amd64.

PCI PASSTHROUGH
     On amd64 where the hardware supports VT-d, PCI devices can be reserved  for
     use by the hypervisor.  Entries consisting of the PCI bus/slot/function are
     added to the pptdevs loader.conf(5) variable.  Additional entries are sepa-
     rated  by spaces.	Host PCI devices that match an entry will be assigned to
     the hypervisor and will not be probed by FreeBSD device drivers.	See  the
     "EXAMPLES" section below for sample usage.

     Note  that  vmm  must be given first the right of refusal to all pci(4) de-
     vices it may need to claim.  As a result, the vmm kernel module almost cer-
     tainly needs to be loaded from loader.conf(5) rather than by adding  it  to
     kld_list in rc.conf(5).

     A	large  number of PCI device entries may require a string longer than the
     128-character limit of loader.conf(5) variables.  The pptdevs2 and pptdevs3
     variables can be used for additional entries.

LOADER TUNABLES
     Tunables can be set at the loader(8) prompt before booting  the  kernel  or
     stored in loader.conf(5).

     hw.vmm.maxcpu
	     Maximum number of virtual CPUs.  The default is the number of phys-
	     ical CPUs in the system.

EXAMPLES
     Reserve three PCI devices for use by the hypervisor: bus 10 slot 0 function
     0, bus 6 slot 5 function 0, and bus 6 slot 5 function 1.

	   pptdevs="10/0/0 6/5/0 6/5/1"

     It  is  possible to detach ppt from a PCI device without rebooting the host
     machine and then attach a host driver, using the devctl(8)  utility.   Sup-
     pose ppt is currently attached to pci0:0:1:0 and we want the host's xhci(4)
     driver to be attached instead:

	   # devctl set driver -f pci0:0:1:0 xhci

     The same can be applied to attach ppt back:

	   # devctl set driver -f pci0:0:1:0 ppt

SEE ALSO
     bhyve(4), loader.conf(5), bhyve(8), bhyveload(8), devctl(8), kldload(8)

HISTORY
     vmm.ko  first  appeared in FreeBSD 10.0.  arm64 and riscv support first ap-
     peared in FreeBSD 15.0.

AUTHORS
     Neel Natu <neel@freebsd.org>
     Peter Grehan <grehan@freebsd.org>

FreeBSD ports 15.quarterly	December 30, 2024			  VMM(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=vmm&sektion=4&manpath=FreeBSD+15.1-RELEASE+and+Ports.quarterly>

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