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VMD(4) 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.bypass_msi By default all VMD devices remap children MSI/MSI-X interrupts into their own. It creates additional isolation, but also com- plicates things due to sharing, etc. Fortunately some VMD de- vices can bypass the remapping. Defaults to 1. hw.vmd.max_msi Limits number of Message Signaled Interrupt (MSI) vectors al- lowed 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 con- strained. Defaults to 3. SEE ALSO graid(8) HISTORY The vmd driver first appeared in FreeBSD 13.0. FreeBSD 15.0 October 6, 2022 VMD(4)
NAME | SYNOPSIS | DESCRIPTION | LOADER TUNABLES | SEE ALSO | HISTORY
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