Messages in this thread Patch in this message | | | From | Kohei Tarumizu <> | Subject | [PATCH v3 6/9] x86: resctrl: pseudo_lock: Fix to restore to original value when re-enabling hardware prefetch register | Date | Wed, 20 Apr 2022 12:02:20 +0900 |
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The current pseudo_lock.c code overwrittes the value of the MSR_MISC_FEATURE_CONTROL to 0 even if the original value is not 0. Therefore, modify it to save and restore the original values.
Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com> --- arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c index db813f819ad6..2d713c20f55f 100644 --- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c +++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c @@ -420,6 +420,7 @@ static int pseudo_lock_fn(void *_rdtgrp) struct pseudo_lock_region *plr = rdtgrp->plr; u32 rmid_p, closid_p; unsigned long i; + u64 saved_msr; #ifdef CONFIG_KASAN /* * The registers used for local register variables are also used @@ -463,6 +464,7 @@ static int pseudo_lock_fn(void *_rdtgrp) * the buffer and evict pseudo-locked memory read earlier from the * cache. */ + saved_msr = __rdmsr(MSR_MISC_FEATURE_CONTROL); __wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0); closid_p = this_cpu_read(pqr_state.cur_closid); rmid_p = this_cpu_read(pqr_state.cur_rmid); @@ -514,7 +516,7 @@ static int pseudo_lock_fn(void *_rdtgrp) __wrmsr(IA32_PQR_ASSOC, rmid_p, closid_p); /* Re-enable the hardware prefetcher(s) */ - wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0); + wrmsrl(MSR_MISC_FEATURE_CONTROL, saved_msr); local_irq_enable(); plr->thread_done = 1; @@ -873,12 +875,14 @@ static int measure_cycles_lat_fn(void *_plr) struct pseudo_lock_region *plr = _plr; unsigned long i; u64 start, end; + u32 saved_low, saved_high; void *mem_r; local_irq_disable(); /* * Disable hardware prefetchers. */ + rdmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0); mem_r = READ_ONCE(plr->kmem); /* @@ -895,7 +899,7 @@ static int measure_cycles_lat_fn(void *_plr) end = rdtsc_ordered(); trace_pseudo_lock_mem_latency((u32)(end - start)); } - wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0); + wrmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); local_irq_enable(); plr->thread_done = 1; wake_up_interruptible(&plr->lock_thread_wq); @@ -945,6 +949,7 @@ static int measure_residency_fn(struct perf_event_attr *miss_attr, unsigned long i; void *mem_r; u64 tmp; + u32 saved_low, saved_high; miss_event = perf_event_create_kernel_counter(miss_attr, plr->cpu, NULL, NULL, NULL); @@ -973,6 +978,7 @@ static int measure_residency_fn(struct perf_event_attr *miss_attr, /* * Disable hardware prefetchers. */ + rdmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0); /* Initialize rest of local variables */ @@ -1031,7 +1037,7 @@ static int measure_residency_fn(struct perf_event_attr *miss_attr, */ rmb(); /* Re-enable hardware prefetchers */ - wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0); + wrmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); local_irq_enable(); out_hit: perf_event_release_kernel(hit_event); -- 2.27.0
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