From a5155c023d6a2c9ff5f4fad5f75117578a58affc Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 19 Jul 2023 19:57:39 +0200 Subject: Revert "intel_idle: Add a "Long HLT" C1 state for the VM guest mode" This reverts commit 0fac214bb75e ("intel_idle: Add a "Long HLT" C1 state for the VM guest mode"), because there is a coding mistake in it and its validity is questioned. Link: https://lore.kernel.org/all/20230711132553.GN3062772@hirez.programming.kicks-ass.net Requested-by: Peter Zijlstra Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 55 ----------------------------------------------- 1 file changed, 55 deletions(-) (limited to 'drivers') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 34201d7ef33e..a80e1f520293 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1287,13 +1287,6 @@ static struct cpuidle_state vmguest_cstates[] __initdata = { .exit_latency = 5, .target_residency = 10, .enter = &intel_idle_hlt, }, - { - .name = "C1L", - .desc = "Long HLT", - .flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_TLB_FLUSHED, - .exit_latency = 5, - .target_residency = 200, - .enter = &intel_idle_hlt, }, { .enter = NULL } }; @@ -2137,45 +2130,6 @@ static void __init intel_idle_cpuidle_devices_uninit(void) cpuidle_unregister_device(per_cpu_ptr(intel_idle_cpuidle_devices, i)); } -/* - * Match up the latency and break even point of the bare metal (cpu based) - * states with the deepest VM available state. - * - * We only want to do this for the deepest state, the ones that has - * the TLB_FLUSHED flag set on the . - * - * All our short idle states are dominated by vmexit/vmenter latencies, - * not the underlying hardware latencies so we keep our values for these. - */ -static void matchup_vm_state_with_baremetal(void) -{ - int cstate; - - for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) { - int matching_cstate; - - if (intel_idle_max_cstate_reached(cstate)) - break; - - if (!cpuidle_state_table[cstate].enter) - break; - - if (!(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_TLB_FLUSHED)) - continue; - - for (matching_cstate = 0; matching_cstate < CPUIDLE_STATE_MAX; ++matching_cstate) { - if (!icpu->state_table[matching_cstate].enter) - break; - if (icpu->state_table[matching_cstate].exit_latency > cpuidle_state_table[cstate].exit_latency) { - cpuidle_state_table[cstate].exit_latency = icpu->state_table[matching_cstate].exit_latency; - cpuidle_state_table[cstate].target_residency = icpu->state_table[matching_cstate].target_residency; - } - } - - } -} - - static int __init intel_idle_vminit(const struct x86_cpu_id *id) { int retval; @@ -2191,15 +2145,6 @@ static int __init intel_idle_vminit(const struct x86_cpu_id *id) if (!intel_idle_cpuidle_devices) return -ENOMEM; - /* - * We don't know exactly what the host will do when we go idle, but as a worst estimate - * we can assume that the exit latency of the deepest host state will be hit for our - * deep (long duration) guest idle state. - * The same logic applies to the break even point for the long duration guest idle state. - * So lets copy these two properties from the table we found for the host CPU type. - */ - matchup_vm_state_with_baremetal(); - intel_idle_cpuidle_driver_init(&intel_idle_driver); retval = cpuidle_register_driver(&intel_idle_driver); -- cgit v1.2.3