The following commit has been merged into the x86/cpu branch of tip: Commit-ID: 822ccfade55b6be7977b364356fcf2d78d8a373a Gitweb: https://git.kernel.org/tip/822ccfade55b6be7977b364356fcf2d78d8a373a Author: Tony Luck <tony.luck@xxxxxxxxx> AuthorDate: Mon, 31 Jan 2022 15:01:09 -08:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Tue, 01 Feb 2022 16:29:26 +01:00 x86/cpu: Read/save PPIN MSR during initialization Currently, the PPIN (Protected Processor Inventory Number) MSR is read by every CPU that processes a machine check, CMCI, or just polls machine check banks from a periodic timer. This is not a "fast" MSR, so this adds to overhead of processing errors. Add a new "ppin" field to the cpuinfo_x86 structure. Read and save the PPIN during initialization. Use this copy in mce_setup() instead of reading the MSR. Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lore.kernel.org/r/20220131230111.2004669-4-tony.luck@xxxxxxxxx --- arch/x86/include/asm/processor.h | 2 ++ arch/x86/kernel/cpu/common.c | 4 ++++ arch/x86/kernel/cpu/mce/core.c | 7 +------ 3 files changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 2c5f12a..a87e7c3 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -119,6 +119,8 @@ struct cpuinfo_x86 { int x86_cache_mbm_width_offset; int x86_power; unsigned long loops_per_jiffy; + /* protected processor identification number */ + u64 ppin; /* cpuid returned max cores value: */ u16 x86_max_cores; u16 apicid; diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 0681c69..64deb77 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -91,14 +91,17 @@ DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id) = BAD_APICID; static struct ppin_info { int feature; int msr_ppin_ctl; + int msr_ppin; } ppin_info[] = { [X86_VENDOR_INTEL] = { .feature = X86_FEATURE_INTEL_PPIN, .msr_ppin_ctl = MSR_PPIN_CTL, + .msr_ppin = MSR_PPIN }, [X86_VENDOR_AMD] = { .feature = X86_FEATURE_AMD_PPIN, .msr_ppin_ctl = MSR_AMD_PPIN_CTL, + .msr_ppin = MSR_AMD_PPIN }, }; @@ -153,6 +156,7 @@ static void ppin_init(struct cpuinfo_x86 *c) /* Is the enable bit set? */ if (val & 2UL) { + c->ppin = __rdmsr(info->msr_ppin); set_cpu_cap(c, info->feature); return; } diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 5818b83..4f1e825 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -138,12 +138,7 @@ void mce_setup(struct mce *m) m->socketid = cpu_data(m->extcpu).phys_proc_id; m->apicid = cpu_data(m->extcpu).initial_apicid; m->mcgcap = __rdmsr(MSR_IA32_MCG_CAP); - - if (this_cpu_has(X86_FEATURE_INTEL_PPIN)) - m->ppin = __rdmsr(MSR_PPIN); - else if (this_cpu_has(X86_FEATURE_AMD_PPIN)) - m->ppin = __rdmsr(MSR_AMD_PPIN); - + m->ppin = cpu_data(m->extcpu).ppin; m->microcode = boot_cpu_data.microcode; }
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