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cpuidle-haltpoll: disable host side polling when kvm virtualized

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When performing guest side polling, it is not necessary to
also perform host side polling.

So disable host side polling, via the new MSR interface,
when loading cpuidle-haltpoll driver.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Marcelo Tosatti
2019-07-03 20:51:29 -03:00
committed by Rafael J. Wysocki
parent 2cffe9f6b9
commit a1c4423b02
5 changed files with 81 additions and 1 deletions
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42
arch/x86/kernel/kvm.c
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@@ -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