cpuidle-haltpoll: disable host side polling when kvm virtualized (a1c4423b) · Commits · 戴 / test

arch/x86/Kconfig

+7 −0

Original line number	Diff line number	Diff line
		@@ -794,6 +794,7 @@ config KVM_GUEST
		bool "KVM Guest support (including kvmclock)"
		depends on PARAVIRT
		select PARAVIRT_CLOCK
		select ARCH_CPUIDLE_HALTPOLL
		default y
		---help---
		This option enables various optimizations for running under the KVM
		@@ -802,6 +803,12 @@ config KVM_GUEST
		underlying device model, the host provides the guest with
		timing infrastructure such as time of day, and system time

		config ARCH_CPUIDLE_HALTPOLL
		def_bool n
		prompt "Disable host haltpoll when loading haltpoll driver"
		help
		If virtualized under KVM, disable host haltpoll.

		config PVH
		bool "Support for running PVH guests"
		---help---

0 → 100644

+8 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0 */
		#ifndef _ARCH_HALTPOLL_H
		#define _ARCH_HALTPOLL_H

		void arch_haltpoll_enable(void);
		void arch_haltpoll_disable(void);

		#endif

+42 −0

Original line number	Diff line number	Diff line
		@@ -875,3 +875,45 @@ void __init kvm_spinlock_init(void)
		}

		#endif /* CONFIG_PARAVIRT_SPINLOCKS */

		#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL

		static void kvm_disable_host_haltpoll(void *i)
		{
		wrmsrl(MSR_KVM_POLL_CONTROL, 0);
		}

		static void kvm_enable_host_haltpoll(void *i)
		{
		wrmsrl(MSR_KVM_POLL_CONTROL, 1);
		}

		void arch_haltpoll_enable(void)
		{
		if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
		printk(KERN_ERR "kvm: host does not support poll control\n");
		printk(KERN_ERR "kvm: host upgrade recommended\n");
		return;
		}

		preempt_disable();
		/* Enable guest halt poll disables host halt poll */
		kvm_disable_host_haltpoll(NULL);
		smp_call_function(kvm_disable_host_haltpoll, NULL, 1);
		preempt_enable();
		}
		EXPORT_SYMBOL_GPL(arch_haltpoll_enable);

		void arch_haltpoll_disable(void)
		{
		if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
		return;

		preempt_disable();
		/* Enable guest halt poll disables host halt poll */
		kvm_enable_host_haltpoll(NULL);
		smp_call_function(kvm_enable_host_haltpoll, NULL, 1);
		preempt_enable();
		}
		EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
		#endif

+8 −1

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@
		#include <linux/module.h>
		#include <linux/sched/idle.h>
		#include <linux/kvm_para.h>
		#include <linux/cpuidle_haltpoll.h>

		static int default_enter_idle(struct cpuidle_device *dev,
		struct cpuidle_driver *drv, int index)
		@@ -47,6 +48,7 @@ static struct cpuidle_driver haltpoll_driver = {

		static int __init haltpoll_init(void)
		{
		int ret;
		struct cpuidle_driver *drv = &haltpoll_driver;

		cpuidle_poll_state_init(drv);
		@@ -54,11 +56,16 @@ static int __init haltpoll_init(void)
		if (!kvm_para_available())
		return 0;

		return cpuidle_register(&haltpoll_driver, NULL);
		ret = cpuidle_register(&haltpoll_driver, NULL);
		if (ret == 0)
		arch_haltpoll_enable();

		return ret;
		}

		static void __exit haltpoll_exit(void)
		{
		arch_haltpoll_disable();
		cpuidle_unregister(&haltpoll_driver);
		}

0 → 100644

+16 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0 */
		#ifndef _CPUIDLE_HALTPOLL_H
		#define _CPUIDLE_HALTPOLL_H

		#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
		#include <asm/cpuidle_haltpoll.h>
		#else
		static inline void arch_haltpoll_enable(void)
		{
		}

		static inline void arch_haltpoll_disable(void)
		{
		}
		#endif
		#endif