From 00433eae1771d355f20c152ddc5976baedb427e2 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Wed, 19 Apr 2023 17:39:44 +0300 Subject: intel_idle: improve C-state flags handling robustness The following C-state flags are currently mutually-exclusive and should not be combined: * IRQ_ENABLE * IBRS * XSTATE There is a warning for the situation when the IRQ_ENABLE flag is combined with the IBRS flag, but no warnings for other combinations. This is inconsistent and prone to errors. Improve the situation by adding warnings for all the unexpected combinations. Add a couple of helpful commentaries too. Signed-off-by: Artem Bityutskiy Reviewed-by: Zhang Rui Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) (limited to 'drivers/idle') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 73ddb1d8cfcf..1de36df15d5a 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1896,20 +1896,28 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv) drv->states[drv->state_count] = cpuidle_state_table[cstate]; state = &drv->states[drv->state_count]; - if ((state->flags & CPUIDLE_FLAG_IRQ_ENABLE) || force_irq_on) { - pr_info("forced intel_idle_irq for state %d\n", cstate); - state->enter = intel_idle_irq; - } - - if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) && - state->flags & CPUIDLE_FLAG_IBRS) { + if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) { + /* + * Combining with XSTATE with IBRS or IRQ_ENABLE flags + * is not currently supported but this driver. + */ + WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IBRS); + WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE); + state->enter = intel_idle_xstate; + } else if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) && + state->flags & CPUIDLE_FLAG_IBRS) { + /* + * IBRS mitigation requires that C-states are entered + * with interrupts disabled. + */ WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE); state->enter = intel_idle_ibrs; + } else if ((state->flags & CPUIDLE_FLAG_IRQ_ENABLE) || + force_irq_on) { + pr_info("forced intel_idle_irq for state %d\n", cstate); + state->enter = intel_idle_irq; } - if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) - state->enter = intel_idle_xstate; - if ((disabled_states_mask & BIT(drv->state_count)) || ((icpu->use_acpi || force_use_acpi) && intel_idle_off_by_default(mwait_hint) && -- cgit v1.2.3