VMD(4)                 FreeBSD Kernel Interfaces Manual                 VMD(4)

NAME
     vmd - Intel Volume Management Device driver

SYNOPSIS
     To compile this driver into the kernel, place the following lines in your
     kernel configuration file:

            device vmd

     Alternatively, to load the driver as a module at boot time, place the
     following line in loader.conf(5):

           vmd_load="YES"

DESCRIPTION
     This driver attaches to Intel VMD devices, representing them as PCI-to-
     PCI bridges and providing access to children PCI devices via new PCI
     domains.  Intel VMD is used by Intel's VROC (Virtual RAID on chip) to
     manage NVMe drives.

LOADER TUNABLES
     The following tunables are settable via loader(8) or sysctl(8):

     hw.vmd.max_msi
             Limits number of Message Signaled Interrupt (MSI) vectors allowed
             to each child device.  VMD can't distinguish MSI vectors of the
             same device, so there are no benefits to have more than one,
             unless it is required by specific device driver.  Defaults to 1.

     hw.vmd.max_msix
             Limits number of Extended Message Signaled Interrupt (MSI-X)
             vectors allowed to each child device.  VMD has limited number of
             interrupt vectors to map children interrupts into, so to
             avoid/reduce sharing children devices/drivers need to be
             constrained.  Defaults to 3.

SEE ALSO
     graid(8)

HISTORY
     The vmd driver first appeared in FreeBSD 13.0.

FreeBSD 13.1-RELEASE-p6         August 31, 2021        FreeBSD 13.1-RELEASE-p6