On Thu, Jan 05, 2023 at 02:23:45PM -0500, Liang, Kan wrote: > On 2023-01-05 1:29 p.m., 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. > > I just want to share that I did more tests on an Ice Lake server (a > different generation from my original report and Tony's machine). > > The same problem can be found as well. > > [ 0.000000] DMI: Intel Corporation M50CYP2SB2U/M50CYP2SB2U, BIOS > SE5C6200.86B.4018.D65.2010201151 10/20/2020 > [ 0.000000] efi: Remove mem375: MMIO range=[0x80000000-0x8fffffff] > (256MB) from e820 map > [ 0.000000] e820: remove [mem 0x80000000-0x8fffffff] reserved > > [ 1.528341] PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem > 0x80000000-0x8fffffff] (base 0x80000000) > [ 1.566605] [Firmware Info]: PCI: MMCONFIG at [mem > 0x80000000-0x8fffffff] not reserved in ACPI motherboard resources > [ 1.566611] PCI: not using MMCONFIG > > This firmware implementation should exist on the existing platforms for > a long time. Yes. Frustrating, but I think we have no choice but to make Linux work with the firmware as it is, whether it is buggy or not. From your first report, I hoped it was isolated to unreleased firmware that had a chance of being fixed, but obviously that's not the case. Bjorn
