diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c index d49e90dc04a4cc..847740c08c97db 100644 --- a/arch/x86/events/intel/uncore_snbep.c +++ b/arch/x86/events/intel/uncore_snbep.c @@ -6474,8 +6474,18 @@ void spr_uncore_cpu_init(void) type = uncore_find_type_by_id(uncore_msr_uncores, UNCORE_SPR_CHA); if (type) { + /* + * The value from the discovery table (stored in the type->num_boxes + * of UNCORE_SPR_CHA) is incorrect on some SPR variants because of a + * firmware bug. Using the value from SPR_MSR_UNC_CBO_CONFIG to replace it. + */ rdmsrl(SPR_MSR_UNC_CBO_CONFIG, num_cbo); - type->num_boxes = num_cbo; + /* + * The MSR doesn't work on the EMR XCC, but the firmware bug doesn't impact + * the EMR XCC. Don't let the value from the MSR replace the existing value. + */ + if (num_cbo) + type->num_boxes = num_cbo; } spr_uncore_iio_free_running.num_boxes = uncore_type_max_boxes(uncore_msr_uncores, UNCORE_SPR_IIO); }