From a5155c023d6a2c9ff5f4fad5f75117578a58affc Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Wed, 19 Jul 2023 19:57:39 +0200
Subject: [PATCH] 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 <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/idle/intel_idle.c | 55 ---------------------------------------
1 file changed, 55 deletions(-)
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 34201d7ef33ed..a80e1f5202937 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);