xref: /freebsd/share/man/man4/vmm.4 (revision 96190b4fef3b4a0cc3ca0606b0c4e3e69a5e6717)
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25.Dd March 6, 2024
26.Dt VMM 4
27.Os
28.Sh NAME
29.Nm vmm.ko
30.Nd "bhyve virtual machine monitor"
31.Sh SYNOPSIS
32To load the driver as a module at boot, add this line to
33.Xr loader.conf 5 :
34.Bd -literal -offset indent
35.Cd vmm_load="YES"
36.Ed
37.Pp
38The module can also be loaded manually with
39.Xr kldload 8 :
40.Bd -literal -offset indent
41kldload vmm
42.Ed
43.Sh DESCRIPTION
44.Nm
45provides the kernel portion of the
46.Xr bhyve 4
47hypervisor.
48.Pp
49An Intel CPU with VT-x/EPT or AMD CPU with SVM support is required.
50.Pp
51PCI device passthrough to a virtual machine requires
52hardware with VT-d support.
53.Sh PCI PASSTHROUGH
54When the hardware supports VT-d, and
55.Nm
56has been loaded at boot time,
57PCI devices can be reserved for use by the hypervisor.
58Entries consisting of the PCI
59.Ar bus Ns / Ns Ar slot Ns / Ns Ar function
60are added to the
61.Va pptdevs
62.Xr loader.conf 5
63variable.
64Additional entries are separated by spaces.
65Host PCI devices that match an entry will be assigned to the hypervisor
66and will not be probed by
67.Fx
68device drivers.
69See the
70.Sx EXAMPLES
71section below for sample usage.
72.Pp
73Note that
74.Nm vmm
75must be given first the right of refusal to all
76.Xr pci 4
77devices it may need to claim.
78As a result, the
79.Nm vmm
80kernel module almost certainly needs to be loaded from
81.Xr loader.conf 5
82rather than by adding it to
83.Va kld_list in
84.Xr rc.conf 5 .
85.Pp
86A large number of PCI device entries may require a string longer than the
87128-character limit of
88.Xr loader.conf 5
89variables.
90The
91.Va pptdevs2
92and
93.Va pptdevs3
94variables can be used for additional entries.
95.Sh LOADER TUNABLES
96Tunables can be set at the
97.Xr loader 8
98prompt before booting the kernel or stored in
99.Xr loader.conf 5 .
100.Bl -tag -width indent
101.It Va hw.vmm.maxcpu
102Maximum number of virtual CPUs.
103The default is the number of physical CPUs in the system.
104.El
105.Sh EXAMPLES
106Reserve three PCI devices for use by the hypervisor: bus 10 slot 0 function 0,
107bus 6 slot 5 function 0, and bus 6 slot 5 function 1.
108.Bd -literal -offset indent
109pptdevs="10/0/0 6/5/0 6/5/1"
110.Ed
111.Sh SEE ALSO
112.Xr bhyve 4 ,
113.Xr loader.conf 5 ,
114.Xr bhyve 8 ,
115.Xr bhyveload 8 ,
116.Xr kldload 8
117.Sh HISTORY
118.Nm vmm.ko
119first appeared in
120.Fx 10.0 .
121.Sh AUTHORS
122.An Neel Natu Aq neel@freebsd.org
123.An Peter Grehan Aq grehan@freebsd.org
124