31:26

0h

RO

RSVD Bits (Reserved0)

RSVD

25:10

7d0bh

RW/P/L

DID ASSIGN Bits (DID_​ASSIGN)

This field is used to program the PCIE standard Device ID register of VMD device.
Only BIOS may program this register field.

9:8

2h

RW/P/L

BUS RESTRICTIONS Bit (BUS_​RESTRICTIONS)

00: VMD-Owned Root Port and PCI Switch Bridges must use the 0-127 of bus numbers (0 is the first bus in CFGBAR at offset 0).

01: VMD-Owned Root Port and PCI Switch Bridges must use the 0,129-255 of bus numbers (0 is the first bus in CFGBAR at offset 0).

10-11: VMD-Owned Root Port and PCI Switch Bridges must use 0,225-255 bus numbers (0 is the first bus in CFGBAR at offset 0).

This field is read only when VMCAP.BUS_​RESTRICT_​CAP bit is clear.

BIOS programs this field to a value that ensures the OS visible busses in the ACPI domain where this VMD resides do not conflict with bus number encodings assigned to VMD.

VMD driver reads this field to select the appropriate range of bus numbers to use in Secondary and Subbordinate Bus registers of PCIe Root Port and Switch Bridges.

VMD driver does not use this field to determine the primary bus number for PCIe Root Port and Switch Bridges owned by VMD. The primary bus number must be the same as the Root Bus number that the VMD Root Complext Integrated Endpoint resides on.

7:4

0h

RW/P/L

DEVID SELECT Bits (DEVID_​SELECT)

NOTE: This field is not used for client!

For Server:
Selects the Device ID that appears in the Device ID register. Values are device specific.
Only BIOS may program this register field.
Volume Management Device v2.0 for Server uses Device ID values 0x28C0 to 0x28CF

3:2

0h

RO

RSVD Field (Reserved1)

RSVD

1

0h

RW/P

MSI RMP DIS (MSI_​RMP_​DIS)

MSI Remapping Disable - When set, causes MSI transactions to bypass the remap indexing that triggers a native VMD MSI-X Table Entries. The original MSI will be set up without indexing, however, the Requestor ID will be changed to match the VMD before being translated by VTd. This bit is programmed by the OS or by the VMD Driver.

0

0h

RW/L

VMD Lock Register (VMDLOCK)

Locks registers in the Volume Management Device. This must be set by BIOS after programming VMD registers.