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Revert "intel_idle: Add a "Long HLT" C1 state for the VM guest mode"

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This reverts commit 0fac214bb7 ("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>
This commit is contained in:
Rafael J. Wysocki 2023-07-19 19:57:39 +02:00
parent d46b0a05bd
commit a5155c023d
1 changed files with 0 additions and 55 deletions
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55
drivers/idle/intel_idle.c
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@ -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);