Messages in this thread | | | Date | Mon, 3 Jul 2023 12:32:55 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 4/4] intel_idle: Add ibrs_off module parameter to force disable IBRS |
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On Tue, Jun 27, 2023 at 10:25:54PM -0400, Waiman Long wrote:
> @@ -69,6 +69,7 @@ static int max_cstate = CPUIDLE_STATE_MAX - 1; > static unsigned int disabled_states_mask __read_mostly; > static unsigned int preferred_states_mask __read_mostly; > static bool force_irq_on __read_mostly; > +static bool ibrs_off __read_mostly; > > static struct cpuidle_device __percpu *intel_idle_cpuidle_devices; > > @@ -1919,12 +1920,15 @@ static void state_update_enter_method(struct cpuidle_state *state, int cstate) > } > > if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) && > - state->flags & CPUIDLE_FLAG_IBRS) { > + ((state->flags & CPUIDLE_FLAG_IBRS) || ibrs_off)) { > /* > * IBRS mitigation requires that C-states are entered > * with interrupts disabled. > */ > - WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE); > + if (ibrs_off && (state->flags & CPUIDLE_FLAG_IRQ_ENABLE)) > + state->flags &= ~CPUIDLE_FLAG_IRQ_ENABLE; > + else > + WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE);
If you're respinning this, you can leave out the else and avoid the indent on the WARN:
+ if (ibrs_off && (state->flags & CPUIDLE_FLAG_IRQ_ENABLE)) + state->flags &= ~CPUIDLE_FLAG_IRQ_ENABLE; WARN_ON_ONCE(state->flags & CPUIDLE_FLAG_IRQ_ENABLE);
Same effect, simpler code and all that.
> state->enter = intel_idle_ibrs; > return; > }
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