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Revert "intel_idle: Add support for using intel_idle in a VM guest us…
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…ing just hlt"

This reverts commit 2f3d08f ("intel_idle: Add support for using
intel_idle in a VM guest using just hlt"), because it causes functional
issues to appear and it is not really useful without a related commit
that got reverted previously.

Link: https://lore.kernel.org/linux-pm/5c7de6d5-7706-c4a5-7c41-146db1269aff@intel.com
Reported-by: Xiaoyao Li <xiaoyao.li@intel.com>
Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Rafael J. Wysocki committed Jul 19, 2023
1 parent a5155c0 commit 5534f44
Showing 1 changed file with 1 addition and 116 deletions.
117 changes: 1 addition & 116 deletions drivers/idle/intel_idle.c
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Original file line number Diff line number Diff line change
Expand Up @@ -199,43 +199,6 @@ static __cpuidle int intel_idle_xstate(struct cpuidle_device *dev,
return __intel_idle(dev, drv, index);
}

static __always_inline int __intel_idle_hlt(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
raw_safe_halt();
raw_local_irq_disable();
return index;
}

/**
* intel_idle_hlt - Ask the processor to enter the given idle state using hlt.
* @dev: cpuidle device of the target CPU.
* @drv: cpuidle driver (assumed to point to intel_idle_driver).
* @index: Target idle state index.
*
* Use the HLT instruction to notify the processor that the CPU represented by
* @dev is idle and it can try to enter the idle state corresponding to @index.
*
* Must be called under local_irq_disable().
*/
static __cpuidle int intel_idle_hlt(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
return __intel_idle_hlt(dev, drv, index);
}

static __cpuidle int intel_idle_hlt_irq_on(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
int ret;

raw_local_irq_enable();
ret = __intel_idle_hlt(dev, drv, index);
raw_local_irq_disable();

return ret;
}

/**
* intel_idle_s2idle - Ask the processor to enter the given idle state.
* @dev: cpuidle device of the target CPU.
Expand Down Expand Up @@ -1279,18 +1242,6 @@ static struct cpuidle_state snr_cstates[] __initdata = {
.enter = NULL }
};

static struct cpuidle_state vmguest_cstates[] __initdata = {
{
.name = "C1",
.desc = "HLT",
.flags = MWAIT2flg(0x00) | CPUIDLE_FLAG_IRQ_ENABLE,
.exit_latency = 5,
.target_residency = 10,
.enter = &intel_idle_hlt, },
{
.enter = NULL }
};

static const struct idle_cpu idle_cpu_nehalem __initconst = {
.state_table = nehalem_cstates,
.auto_demotion_disable_flags = NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE,
Expand Down Expand Up @@ -1890,16 +1841,6 @@ static bool __init intel_idle_verify_cstate(unsigned int mwait_hint)

static void state_update_enter_method(struct cpuidle_state *state, int cstate)
{
if (state->enter == intel_idle_hlt) {
if (force_irq_on) {
pr_info("forced intel_idle_irq for state %d\n", cstate);
state->enter = intel_idle_hlt_irq_on;
}
return;
}
if (state->enter == intel_idle_hlt_irq_on)
return; /* no update scenarios */

if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) {
/*
* Combining with XSTATE with IBRS or IRQ_ENABLE flags
Expand Down Expand Up @@ -1933,21 +1874,6 @@ static void state_update_enter_method(struct cpuidle_state *state, int cstate)
}
}

/*
* For mwait based states, we want to verify the cpuid data to see if the state
* is actually supported by this specific CPU.
* For non-mwait based states, this check should be skipped.
*/
static bool should_verify_mwait(struct cpuidle_state *state)
{
if (state->enter == intel_idle_hlt)
return false;
if (state->enter == intel_idle_hlt_irq_on)
return false;

return true;
}

static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
{
int cstate;
Expand Down Expand Up @@ -1996,7 +1922,7 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
}

mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
if (should_verify_mwait(&cpuidle_state_table[cstate]) && !intel_idle_verify_cstate(mwait_hint))
if (!intel_idle_verify_cstate(mwait_hint))
continue;

/* Structure copy. */
Expand Down Expand Up @@ -2130,45 +2056,6 @@ static void __init intel_idle_cpuidle_devices_uninit(void)
cpuidle_unregister_device(per_cpu_ptr(intel_idle_cpuidle_devices, i));
}

static int __init intel_idle_vminit(const struct x86_cpu_id *id)
{
int retval;

cpuidle_state_table = vmguest_cstates;

icpu = (const struct idle_cpu *)id->driver_data;

pr_debug("v" INTEL_IDLE_VERSION " model 0x%X\n",
boot_cpu_data.x86_model);

intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
if (!intel_idle_cpuidle_devices)
return -ENOMEM;

intel_idle_cpuidle_driver_init(&intel_idle_driver);

retval = cpuidle_register_driver(&intel_idle_driver);
if (retval) {
struct cpuidle_driver *drv = cpuidle_get_driver();
printk(KERN_DEBUG pr_fmt("intel_idle yielding to %s\n"),
drv ? drv->name : "none");
goto init_driver_fail;
}

retval = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "idle/intel:online",
intel_idle_cpu_online, NULL);
if (retval < 0)
goto hp_setup_fail;

return 0;
hp_setup_fail:
intel_idle_cpuidle_devices_uninit();
cpuidle_unregister_driver(&intel_idle_driver);
init_driver_fail:
free_percpu(intel_idle_cpuidle_devices);
return retval;
}

static int __init intel_idle_init(void)
{
const struct x86_cpu_id *id;
Expand All @@ -2187,8 +2074,6 @@ static int __init intel_idle_init(void)
id = x86_match_cpu(intel_idle_ids);
if (id) {
if (!boot_cpu_has(X86_FEATURE_MWAIT)) {
if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
return intel_idle_vminit(id);
pr_debug("Please enable MWAIT in BIOS SETUP\n");
return -ENODEV;
}
Expand Down

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