From b034c19f9f61c8b6f2435aa2e77f52348ebde767 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 22 May 2009 13:52:19 +0200 Subject: [PATCH] x86: MSR: add methods for writing of an MSR on several CPUs Provide for concurrent MSR writes on all the CPUs in the cpumask. Also, add a temporary workaround for smp_call_function_many which skips the CPU we're executing on. Bart: zero out rv struct which is allocated on stack. CC: H. Peter Anvin Signed-off-by: Borislav Petkov Signed-off-by: Bartlomiej Zolnierkiewicz --- arch/x86/include/asm/msr.h | 12 ++++++ arch/x86/lib/msr.c | 98 +++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 104 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 5e12132..2260376 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -227,6 +227,8 @@ do { \ #ifdef CONFIG_SMP int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h); int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h); +void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs); +void wrmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs); int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h); int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h); #else /* CONFIG_SMP */ @@ -240,6 +242,16 @@ static inline int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h) wrmsr(msr_no, l, h); return 0; } +static inline void rdmsr_on_cpus(const cpumask_t *m, u32 msr_no, + struct msr *msrs) +{ + rdmsr_on_cpu(0, msr_no, &(msrs[0].l), &(msrs[0].h)); +} +static inline void wrmsr_on_cpus(const cpumask_t *m, u32 msr_no, + struct msr *msrs) +{ + wrmsr_on_cpu(0, msr_no, msrs[0].l, msrs[0].h); +} static inline int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) { diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c index cade714..1440b9c 100644 --- a/arch/x86/lib/msr.c +++ b/arch/x86/lib/msr.c @@ -6,21 +6,37 @@ struct msr_info { u32 msr_no; struct msr reg; + struct msr *msrs; + int off; int err; }; static void __rdmsr_on_cpu(void *info) { struct msr_info *rv = info; + struct msr *reg; + int this_cpu = raw_smp_processor_id(); - rdmsr(rv->msr_no, rv->reg.l, rv->reg.h); + if (rv->msrs) + reg = &rv->msrs[this_cpu - rv->off]; + else + reg = &rv->reg; + + rdmsr(rv->msr_no, reg->l, reg->h); } static void __wrmsr_on_cpu(void *info) { struct msr_info *rv = info; + struct msr *reg; + int this_cpu = raw_smp_processor_id(); + + if (rv->msrs) + reg = &rv->msrs[this_cpu - rv->off]; + else + reg = &rv->reg; - wrmsr(rv->msr_no, rv->reg.l, rv->reg.h); + wrmsr(rv->msr_no, reg->l, reg->h); } int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) @@ -28,6 +44,8 @@ int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) int err; struct msr_info rv; + memset(&rv, 0, sizeof(rv)); + rv.msr_no = msr_no; err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1); *l = rv.reg.l; @@ -35,12 +53,15 @@ int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) return err; } +EXPORT_SYMBOL(rdmsr_on_cpu); int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h) { int err; struct msr_info rv; + memset(&rv, 0, sizeof(rv)); + rv.msr_no = msr_no; rv.reg.l = l; rv.reg.h = h; @@ -48,6 +69,70 @@ int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h) return err; } +EXPORT_SYMBOL(wrmsr_on_cpu); + +/* rdmsr on a bunch of CPUs + * + * @mask: which CPUs + * @msr_no: which MSR + * @msrs: array of MSR values + * + */ +void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs) +{ + struct msr_info rv; + int this_cpu; + + memset(&rv, 0, sizeof(rv)); + + rv.off = cpumask_first(mask); + rv.msrs = msrs; + rv.msr_no = msr_no; + + preempt_disable(); + /* + * FIXME: handle the CPU we're executing on separately for now until + * smp_call_function_many has been fixed to not skip it. + */ + this_cpu = raw_smp_processor_id(); + smp_call_function_single(this_cpu, __rdmsr_on_cpu, &rv, 1); + + smp_call_function_many(mask, __rdmsr_on_cpu, &rv, 1); + preempt_enable(); +} +EXPORT_SYMBOL(rdmsr_on_cpus); + +/* + * wrmsr on a bunch of CPUs + * + * @mask: which CPUs + * @msr_no: which MSR + * @msrs: array of MSR values + * + */ +void wrmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs) +{ + struct msr_info rv; + int this_cpu; + + memset(&rv, 0, sizeof(rv)); + + rv.off = cpumask_first(mask); + rv.msrs = msrs; + rv.msr_no = msr_no; + + preempt_disable(); + /* + * FIXME: handle the CPU we're executing on separately for now until + * smp_call_function_many has been fixed to not skip it. + */ + this_cpu = raw_smp_processor_id(); + smp_call_function_single(this_cpu, __wrmsr_on_cpu, &rv, 1); + + smp_call_function_many(mask, __wrmsr_on_cpu, &rv, 1); + preempt_enable(); +} +EXPORT_SYMBOL(wrmsr_on_cpus); /* These "safe" variants are slower and should be used when the target MSR may not actually exist. */ @@ -70,6 +155,8 @@ int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) int err; struct msr_info rv; + memset(&rv, 0, sizeof(rv)); + rv.msr_no = msr_no; err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1); *l = rv.reg.l; @@ -77,12 +164,15 @@ int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h) return err ? err : rv.err; } +EXPORT_SYMBOL(rdmsr_safe_on_cpu); int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h) { int err; struct msr_info rv; + memset(&rv, 0, sizeof(rv)); + rv.msr_no = msr_no; rv.reg.l = l; rv.reg.h = h; @@ -90,8 +180,4 @@ int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h) return err ? err : rv.err; } - -EXPORT_SYMBOL(rdmsr_on_cpu); -EXPORT_SYMBOL(wrmsr_on_cpu); -EXPORT_SYMBOL(rdmsr_safe_on_cpu); EXPORT_SYMBOL(wrmsr_safe_on_cpu); -- 2.7.4