Bjorn Helgaas wrote: > On Thu, Jan 05, 2023 at 06:04:52PM +0000, Luck, Tony wrote: > > > Hi Tony, can you share a dmesg log? Does it look like the same thing > > > Kan reported, where the ECAM space is reported only via an > > > EfiMemoryMappedIO region and is not otherwise reserved by firmware? > > > > Attached are serial logs. "broken" is the one from v6.2-rc2, "revert" is the > > one with your commit reverted. > > > > I don't see the string "ECAM" in either of them. > > Yeah, "ECAM" is what the PCIe spec calls it, but Linux logging uses > "MMCONFIG". Probably should change that. > > Anyway, your dmesg log shows the same problem: > > DMI: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRBDXSD1.86B.0338.V01.1603162127 03/16/2016 > efi: Remove mem48: MMIO range=[0x80000000-0x8fffffff] (256MB) from e820 map > PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem 0x80000000-0x8fffffff] (base 0x80000000) > [Firmware Info]: PCI: MMCONFIG at [mem 0x80000000-0x8fffffff] not reserved in ACPI motherboard resources > PCI: not using MMCONFIG > acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended configuration space under this bridge > > Apparently the only mention of [mem 0x80000000-0x8fffffff] in the > firmware/kernel interface is as an EfiMemoryMappedIO region. > > I think this is a firmware bug, but obviously we're going to have to > figure out a way around it. Definitely an ambiguity / conflict, but not sure it is a bug when you look at from the perspective of how would an EFI runtime service use ECAM/MMCONFIG space? Would it be enough to add this clarification in "EFI 2.9 Table 7-6 Memory Type Usage after ExitBootServices()"? s/This memory is not used by the OS./This memory is not used by the OS, unless ACPI declares it for another puporse./
