I'm Seunghun Han and work at the Affiliated Institute of ETRI. I got an AMD system which had a Ryzen Threadripper 1950X and MSI mainboard, and I had a problem with AMD's fTPM. My machine showed an error message below, and the fTPM didn't work because of it. [ 5.732084] tpm_crb MSFT0101:00: can't request region for resource [mem 0x79b4f000-0x79b4ffff] [ 5.732089] tpm_crb: probe of MSFT0101:00 failed with error -16 When I saw the e820 map and iomem, I found two fTPM regions were in the ACPI NVS area. The regions are below. 79a39000-79b6afff : ACPI Non-volatile Storage 79b4b000-79b4bfff : MSFT0101:00 79b4f000-79b4ffff : MSFT0101:00 After analyzing this issue, I found out that a busy bit was set to the ACPI NVS area, and the Linux kernel didn't allow the TPM CRB driver to assign CRB regions in it. To support AMD's fTPM, I removed the busy bit from the ACPI NVS area like the reserved area so that AMD's fTPM regions could be assigned in it. Signed-off-by: Seunghun Han <kkamagui@xxxxxxxxx> --- arch/x86/kernel/e820.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 7da2bcd2b8eb..0d721df8900e 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1085,11 +1085,12 @@ static bool __init do_mark_busy(enum e820_type type, struct resource *res) case E820_TYPE_RESERVED: case E820_TYPE_PRAM: case E820_TYPE_PMEM: + /* AMD's fTPM regions are in the ACPI NVS area */ + case E820_TYPE_NVS: return false; case E820_TYPE_RESERVED_KERN: case E820_TYPE_RAM: case E820_TYPE_ACPI: - case E820_TYPE_NVS: case E820_TYPE_UNUSABLE: default: return true; -- 2.21.0
