diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-07-29 19:22:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-07-29 19:22:21 -0700 |
| commit | 4dd39ddeb68fbb6d068611f2cc647948dc7dfca0 (patch) | |
| tree | 2daf268154b367b2a2e557dfa43c41d9e3a3e83a | |
| parent | 1645f6ab966b828bc160c23626d071914debfa79 (diff) | |
| parent | 5bf2f5119b9e957f773a22f226974166b58cff32 (diff) | |
Merge tag 'x86-cpu-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu update from Ingo Molnar:
"Add user-space CPUID faulting support for AMD CPUs"
* tag 'x86-cpu-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/CPU/AMD: Add CPUID faulting support
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 3 | ||||
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 20 |
4 files changed, 21 insertions, 7 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 286d509f9363..602957dd2609 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -458,9 +458,12 @@ #define X86_FEATURE_LFENCE_RDTSC (20*32+ 2) /* LFENCE always serializing / synchronizes RDTSC */ #define X86_FEATURE_VERW_CLEAR (20*32+ 5) /* The memory form of VERW mitigates TSA */ #define X86_FEATURE_NULL_SEL_CLR_BASE (20*32+ 6) /* Null Selector Clears Base */ + #define X86_FEATURE_AUTOIBRS (20*32+ 8) /* Automatic IBRS */ #define X86_FEATURE_NO_SMM_CTL_MSR (20*32+ 9) /* SMM_CTL MSR is not present */ +#define X86_FEATURE_GP_ON_USER_CPUID (20*32+17) /* User CPUID faulting */ + #define X86_FEATURE_PREFETCHI (20*32+20) /* Prefetch Data/Instruction to Cache Level */ #define X86_FEATURE_SBPB (20*32+27) /* Selective Branch Prediction Barrier */ #define X86_FEATURE_IBPB_BRTYPE (20*32+28) /* MSR_PRED_CMD[IBPB] flushes all branch type predictions */ diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 5cfb5d74dd5f..2d5595bdfa27 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -831,6 +831,7 @@ #define MSR_K7_HWCR_SMMLOCK BIT_ULL(MSR_K7_HWCR_SMMLOCK_BIT) #define MSR_K7_HWCR_IRPERF_EN_BIT 30 #define MSR_K7_HWCR_IRPERF_EN BIT_ULL(MSR_K7_HWCR_IRPERF_EN_BIT) +#define MSR_K7_HWCR_CPUID_USER_DIS_BIT 35 #define MSR_K7_FID_VID_CTL 0xc0010041 #define MSR_K7_FID_VID_STATUS 0xc0010042 #define MSR_K7_HWCR_CPB_DIS_BIT 25 diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 329ee185d8cc..a5ece6ebe8a7 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -530,9 +530,11 @@ static void bsp_init_amd(struct cpuinfo_x86 *c) } bsp_determine_snp(c); - tsa_init(c); + if (cpu_has(c, X86_FEATURE_GP_ON_USER_CPUID)) + setup_force_cpu_cap(X86_FEATURE_CPUID_FAULT); + return; warn: diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index a838be04f874..1b7960cf6eb0 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -334,13 +334,21 @@ DEFINE_PER_CPU(u64, msr_misc_features_shadow); static void set_cpuid_faulting(bool on) { - u64 msrval; - msrval = this_cpu_read(msr_misc_features_shadow); - msrval &= ~MSR_MISC_FEATURES_ENABLES_CPUID_FAULT; - msrval |= (on << MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT); - this_cpu_write(msr_misc_features_shadow, msrval); - wrmsrq(MSR_MISC_FEATURES_ENABLES, msrval); + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { + u64 msrval; + + msrval = this_cpu_read(msr_misc_features_shadow); + msrval &= ~MSR_MISC_FEATURES_ENABLES_CPUID_FAULT; + msrval |= (on << MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT); + this_cpu_write(msr_misc_features_shadow, msrval); + wrmsrq(MSR_MISC_FEATURES_ENABLES, msrval); + } else if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { + if (on) + msr_set_bit(MSR_K7_HWCR, MSR_K7_HWCR_CPUID_USER_DIS_BIT); + else + msr_clear_bit(MSR_K7_HWCR, MSR_K7_HWCR_CPUID_USER_DIS_BIT); + } } static void disable_cpuid(void) |