Commit 5534f446 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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

This reverts commit 2f3d08f0 ("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: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Requested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent a5155c02

drivers/idle/intel_idle.c

+1 −116
Original line number Diff line number Diff line
@@ -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.
@@ -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,
@@ -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
@@ -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;
@@ -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. */
@@ -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;
@@ -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;

		}