b034c19f9f
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 <hpa@zytor.com> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
183 lines
3.6 KiB
C
183 lines
3.6 KiB
C
#include <linux/module.h>
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#include <linux/preempt.h>
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#include <linux/smp.h>
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#include <asm/msr.h>
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struct msr_info {
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u32 msr_no;
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struct msr reg;
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struct msr *msrs;
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int off;
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int err;
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};
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static void __rdmsr_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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struct msr *reg;
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int this_cpu = raw_smp_processor_id();
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if (rv->msrs)
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reg = &rv->msrs[this_cpu - rv->off];
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else
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reg = &rv->reg;
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rdmsr(rv->msr_no, reg->l, reg->h);
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}
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static void __wrmsr_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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struct msr *reg;
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int this_cpu = raw_smp_processor_id();
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if (rv->msrs)
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reg = &rv->msrs[this_cpu - rv->off];
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else
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reg = &rv->reg;
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wrmsr(rv->msr_no, reg->l, reg->h);
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}
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int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
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{
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int err;
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struct msr_info rv;
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memset(&rv, 0, sizeof(rv));
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rv.msr_no = msr_no;
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err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
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*l = rv.reg.l;
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*h = rv.reg.h;
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return err;
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}
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EXPORT_SYMBOL(rdmsr_on_cpu);
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int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
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{
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int err;
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struct msr_info rv;
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memset(&rv, 0, sizeof(rv));
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rv.msr_no = msr_no;
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rv.reg.l = l;
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rv.reg.h = h;
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err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);
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return err;
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}
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EXPORT_SYMBOL(wrmsr_on_cpu);
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/* rdmsr on a bunch of CPUs
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*
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* @mask: which CPUs
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* @msr_no: which MSR
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* @msrs: array of MSR values
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*
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*/
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void rdmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
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{
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struct msr_info rv;
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int this_cpu;
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memset(&rv, 0, sizeof(rv));
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rv.off = cpumask_first(mask);
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rv.msrs = msrs;
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rv.msr_no = msr_no;
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preempt_disable();
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/*
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* FIXME: handle the CPU we're executing on separately for now until
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* smp_call_function_many has been fixed to not skip it.
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*/
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this_cpu = raw_smp_processor_id();
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smp_call_function_single(this_cpu, __rdmsr_on_cpu, &rv, 1);
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smp_call_function_many(mask, __rdmsr_on_cpu, &rv, 1);
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preempt_enable();
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}
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EXPORT_SYMBOL(rdmsr_on_cpus);
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/*
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* wrmsr on a bunch of CPUs
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*
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* @mask: which CPUs
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* @msr_no: which MSR
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* @msrs: array of MSR values
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*
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*/
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void wrmsr_on_cpus(const cpumask_t *mask, u32 msr_no, struct msr *msrs)
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{
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struct msr_info rv;
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int this_cpu;
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memset(&rv, 0, sizeof(rv));
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rv.off = cpumask_first(mask);
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rv.msrs = msrs;
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rv.msr_no = msr_no;
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preempt_disable();
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/*
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* FIXME: handle the CPU we're executing on separately for now until
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* smp_call_function_many has been fixed to not skip it.
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*/
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this_cpu = raw_smp_processor_id();
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smp_call_function_single(this_cpu, __wrmsr_on_cpu, &rv, 1);
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smp_call_function_many(mask, __wrmsr_on_cpu, &rv, 1);
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preempt_enable();
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}
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EXPORT_SYMBOL(wrmsr_on_cpus);
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/* These "safe" variants are slower and should be used when the target MSR
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may not actually exist. */
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static void __rdmsr_safe_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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rv->err = rdmsr_safe(rv->msr_no, &rv->reg.l, &rv->reg.h);
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}
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static void __wrmsr_safe_on_cpu(void *info)
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{
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struct msr_info *rv = info;
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rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
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}
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int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
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{
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int err;
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struct msr_info rv;
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memset(&rv, 0, sizeof(rv));
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rv.msr_no = msr_no;
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err = smp_call_function_single(cpu, __rdmsr_safe_on_cpu, &rv, 1);
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*l = rv.reg.l;
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*h = rv.reg.h;
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return err ? err : rv.err;
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}
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EXPORT_SYMBOL(rdmsr_safe_on_cpu);
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int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
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{
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int err;
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struct msr_info rv;
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memset(&rv, 0, sizeof(rv));
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rv.msr_no = msr_no;
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rv.reg.l = l;
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rv.reg.h = h;
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err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);
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return err ? err : rv.err;
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}
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EXPORT_SYMBOL(wrmsr_safe_on_cpu);
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