On Mon, Jan 20, 2014 at 04:36:57PM +0100, Gerd Hoffmann wrote: > > 4.1.2. > > MCFG Table Description > > > > > > ... > > > > If the operating system does not natively comprehend reserving the MMCFG > > region, the MMCFG region must be reserved by firmware. The address range > > reported in the MCFG table or by _CBA method (see Section 4.1.3) must be > > reserved by declaring a motherboard resource. > > We don't do this today. > > > For most systems, the > > motherboard resource would appear at the root of the ACPI namespace > > (under \_SB) in a node with a _HID of EISAID (PNP0C02), and the > > resources in this case should not be claimed in the root PCI bus’s _CRS. > > Which I read as _in case it is at the root of the apci namespace_ it > should not be claimed in PCI0._CRS. Which makes sense. > > My laptop has it reserved in a \_SB\PCI0\LPC\SIO device instead: > > Device (LPC) > { > Name (_ADR, 0x001F0000) // _ADR: Address > Name (_S3D, 0x03) // _S3D: S3 Device State > Name (RID, 0x00) > Device (SIO) > { > Name (_HID, EisaId ("PNP0C02")) > Name (_UID, 0x00) // _UID: Unique ID > Name (SCRS, ResourceTemplate () > { > [ ... ] > Memory32Fixed (ReadWrite, > 0xF8000000, // Address Base > 0x04000000, // Address Length > ) > [ ... ] > > cheers, > Gerd >
We can try, but Igor tried to do something like this recently ( for IO resources) and windows guests kept crashing unless he made holes in _CRS.