Messages in this thread | | | From | Tony Luck <> | Subject | [PATCH v2 0/6] PPIN (Protected Processor Inventory Number) updates | Date | Fri, 21 Jan 2022 09:47:37 -0800 |
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v2 starts with an extra patch over v1. Adding INTEL_FAM6_ICELAKE_D to the list of legacy processors that support PPIN. I've marked this patch for stable. I don't think the rest of the patches are candidates for stable or long term support kernels.
The rest of the patches are updates from v1 of the series starts out with two changes that I expect are uncontroversial. Later parts get progressively more "RFC".
1) Simple cleanup to merge Intel and AMD duplicated code to test for presence of PPIN and check whether it is enabled.
2) Long overdue update from Intel to enumerate the PPIN and PPIN_CTL MSRs. See the December 2021 Software Developers Manual
{RFC factor moves to medium here}
3) Code to scan machine check banks re-reads the PPIN every time banks are scanned (whether for a machine check, a CMCI, or just a periodic poll). Since PPIN never changes, this seems like unnecessary overhead. Read the MSR once (per CPU) and save to memory.
{RFC factor moves to high for last two parts}
4) Refactor as prep for last part.
5) Add "ppin" to /sys/devices/system/cpu/cpu*/topology/ppin
The big question for this part is whether there is a better place to expose this value. I'm open to other suggestions.
I do think it is useful to do so. An "inventory" number that stays hidden until there is an error that causes it to show up in a machine check log is user hostile.
Changes since V1: ----------------- Added INTEL_FAM6_ICELAKE_D Use X86_MATCH_FEATURE() instead of X86_MATCH_VENDOR_FEATURE Spelling: s/prescence/presence/ s/CPUS/CPUs/ Print the hex value of PPIN with a leading "0x" Fix the Subject line commit prefixes to use "x86/cpu" and "topology/sysfs" Move the introduction of the "msr_ppin" field to the patch where used.
Rewrite the commit comment justifying adding ppin to /sys/.../topology
Upcoming use case for user accessible ppin is for reporting issues found by on-line testing of CPU cores. The MSRs for this are public in the latest SDM (look for MSR_ACTIVATE_SCAN and a bunch of others in the same section) but the SDM is currently light on details on what it does or how to use it. Linux patches to enable coming soon.
Tony Luck (6): x86/cpu: Add Xeon Icelake-D to list of CPUs that support PPIN x86/cpu: Merge Intel and AMD ppin_init() functions x86/cpu: X86_FEATURE_INTEL_PPIN finally has a CPUID bit x86/cpu: Read/save PPIN MSR during initialization topology/sysfs: Add format parameter to macro defining "show" functions for proc topology/sysfs: Add PPIN in sysfs under cpu topology
.../ABI/stable/sysfs-devices-system-cpu | 4 + .../ABI/testing/sysfs-devices-system-cpu | 6 ++ arch/x86/include/asm/processor.h | 2 + arch/x86/include/asm/topology.h | 1 + arch/x86/kernel/cpu/amd.c | 30 ------- arch/x86/kernel/cpu/common.c | 79 +++++++++++++++++++ arch/x86/kernel/cpu/mce/core.c | 7 +- arch/x86/kernel/cpu/mce/intel.c | 41 ---------- arch/x86/kernel/cpu/scattered.c | 1 + drivers/base/topology.c | 20 +++-- include/linux/topology.h | 3 + 11 files changed, 109 insertions(+), 85 deletions(-)
base-commit: 2c271fe77d52a0555161926c232cd5bc07178b39 -- 2.31.1
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