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Commit fd10cde9 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
Browse files

KVM paravirt: Add async PF initialization to PV guest. 



Enable async PF in a guest if async PF capability is discovered.

Acked-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 344d9588

Documentation/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -1707,6 +1707,9 @@ and is between 256 and 4096 characters. It is defined in the file 


	no-kvmclock	[X86,KVM] Disable paravirtualized KVM clock driver



	no-kvmapf	[X86,KVM] Disable paravirtualized asynchronous page

			fault handling.



	nolapic		[X86-32,APIC] Do not enable or use the local APIC.



	nolapic_timer	[X86-32,APIC] Do not use the local APIC timer.

arch/x86/include/asm/kvm_para.h

+6 −0
Original line number Diff line number Diff line
@@ -65,6 +65,12 @@ struct kvm_mmu_op_release_pt { 
	__u64 pt_phys;

};



struct kvm_vcpu_pv_apf_data {

	__u32 reason;

	__u8 pad[60];

	__u32 enabled;

};



#ifdef __KERNEL__

#include <asm/processor.h>

arch/x86/kernel/kvm.c

+92 −0
Original line number Diff line number Diff line
@@ -27,16 +27,30 @@ 
#include <linux/mm.h>

#include <linux/highmem.h>

#include <linux/hardirq.h>

#include <linux/notifier.h>

#include <linux/reboot.h>

#include <asm/timer.h>

#include <asm/cpu.h>



#define MMU_QUEUE_SIZE 1024



static int kvmapf = 1;



static int parse_no_kvmapf(char *arg)

{

        kvmapf = 0;

        return 0;

}



early_param("no-kvmapf", parse_no_kvmapf);



struct kvm_para_state {

	u8 mmu_queue[MMU_QUEUE_SIZE];

	int mmu_queue_len;

};



static DEFINE_PER_CPU(struct kvm_para_state, para_state);

static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);



static struct kvm_para_state *kvm_para_state(void)

{
@@ -231,12 +245,86 @@ static void __init paravirt_ops_setup(void) 
#endif

}



void __cpuinit kvm_guest_cpu_init(void)

{

	if (!kvm_para_available())

		return;



	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {

		u64 pa = __pa(&__get_cpu_var(apf_reason));



		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);

		__get_cpu_var(apf_reason).enabled = 1;

		printk(KERN_INFO"KVM setup async PF for cpu %d\n",

		       smp_processor_id());

	}

}



static void kvm_pv_disable_apf(void *unused)

{

	if (!__get_cpu_var(apf_reason).enabled)

		return;



	wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);

	__get_cpu_var(apf_reason).enabled = 0;



	printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",

	       smp_processor_id());

}



static int kvm_pv_reboot_notify(struct notifier_block *nb,

				unsigned long code, void *unused)

{

	if (code == SYS_RESTART)

		on_each_cpu(kvm_pv_disable_apf, NULL, 1);

	return NOTIFY_DONE;

}



static struct notifier_block kvm_pv_reboot_nb = {

	.notifier_call = kvm_pv_reboot_notify,

};



#ifdef CONFIG_SMP

static void __init kvm_smp_prepare_boot_cpu(void)

{

	WARN_ON(kvm_register_clock("primary cpu clock"));

	kvm_guest_cpu_init();

	native_smp_prepare_boot_cpu();

}



static void kvm_guest_cpu_online(void *dummy)

{

	kvm_guest_cpu_init();

}



static void kvm_guest_cpu_offline(void *dummy)

{

	kvm_pv_disable_apf(NULL);

}



static int __cpuinit kvm_cpu_notify(struct notifier_block *self,

				    unsigned long action, void *hcpu)

{

	int cpu = (unsigned long)hcpu;

	switch (action) {

	case CPU_ONLINE:

	case CPU_DOWN_FAILED:

	case CPU_ONLINE_FROZEN:

		smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);

		break;

	case CPU_DOWN_PREPARE:

	case CPU_DOWN_PREPARE_FROZEN:

		smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);

		break;

	default:

		break;

	}

	return NOTIFY_OK;

}



static struct notifier_block __cpuinitdata kvm_cpu_notifier = {

        .notifier_call  = kvm_cpu_notify,

};

#endif



void __init kvm_guest_init(void)
@@ -245,7 +333,11 @@ void __init kvm_guest_init(void) 
		return;



	paravirt_ops_setup();

	register_reboot_notifier(&kvm_pv_reboot_nb);

#ifdef CONFIG_SMP

	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;

	register_cpu_notifier(&kvm_cpu_notifier);

#else

	kvm_guest_cpu_init();

#endif

}