https://bugzilla.kernel.org/show_bug.cgi?id=214259 Bjorn Helgaas (bjorn@xxxxxxxxxxx) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bjorn@xxxxxxxxxxx --- Comment #25 from Bjorn Helgaas (bjorn@xxxxxxxxxxx) --- I don't know the connection to the DMAR faults, but from the first log (https://bugzilla.kernel.org/attachment.cgi?id=298567): BIOS-e820: [mem 0x000000006bc00000-0x00000000efffffff] reserved pci_bus 0000:00: root bus resource [mem 0x71000000-0xdfffffff window] This entire PCI host bridge aperture is "reserved" in the E820 map, which means we won't allocate any PCI BARs in that area, which means hot-add won't work. The current workaround for this is https://git.kernel.org/linus/d341838d776a ("x86/PCI: Disable E820 reserved region clipping via quirks"), which appeared in v5.19. I think the underlying issue is that this machine has EFI, Linux converts the EFI memory map to E820 format, and it converts EFI_MEMORY_MAPPED_IO to E820_TYPE_RESERVED. EFI_MEMORY_MAPPED_IO means "the OS must map this memory for use by EFI runtime services." It does *not* mean "the OS can never use this memory." I think Linux should omit EFI_MEMORY_MAPPED_IO areas completely from the E820 map. This is basically the same issue as bug #216565. I attached a patch there to omit EFI_MEMORY_MAPPED_IO. I would love to hear from anybody with a Clevo machine that shows similar problems. If you can, please boot with the patch at https://bugzilla.kernel.org/attachment.cgi?id=303123 with the "efi=debug" kernel parameter, open new bugzilla with the complete dmesg log, and assign it to me. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
