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Commit 3dc4f7cf authored by Marcelo Tosatti's avatar Marcelo Tosatti
Browse files

x86: kvm guest: pvclock vsyscall support 



Hook into generic pvclock vsyscall code, with the aim to
allow userspace to have visibility into pvclock data.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 71056ae2

arch/x86/include/asm/kvm_guest.h

0 → 100644
+6 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_KVM_GUEST_H

#define _ASM_X86_KVM_GUEST_H



int kvm_setup_vsyscall_timeinfo(void);



#endif /* _ASM_X86_KVM_GUEST_H */

arch/x86/kernel/kvm.c

+13 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <asm/apic.h>

#include <asm/apicdef.h>

#include <asm/hypervisor.h>

#include <asm/kvm_guest.h>



static int kvmapf = 1;
@@ -62,6 +63,15 @@ static int parse_no_stealacc(char *arg) 


early_param("no-steal-acc", parse_no_stealacc);



static int kvmclock_vsyscall = 1;

static int parse_no_kvmclock_vsyscall(char *arg)

{

        kvmclock_vsyscall = 0;

        return 0;

}



early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);



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

static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);

static int has_steal_clock = 0;
@@ -471,6 +481,9 @@ void __init kvm_guest_init(void) 
	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))

		apic_set_eoi_write(kvm_guest_apic_eoi_write);



	if (kvmclock_vsyscall)

		kvm_setup_vsyscall_timeinfo();



#ifdef CONFIG_SMP

	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;

	register_cpu_notifier(&kvm_cpu_notifier);

arch/x86/kernel/kvmclock.c

+42 −12
Original line number Diff line number Diff line
@@ -40,11 +40,7 @@ static int parse_no_kvmclock(char *arg) 
early_param("no-kvmclock", parse_no_kvmclock);



/* The hypervisor will put information about time periodically here */

struct pvclock_aligned_vcpu_time_info {

	struct pvclock_vcpu_time_info clock;

} __attribute__((__aligned__(SMP_CACHE_BYTES)));



static struct pvclock_aligned_vcpu_time_info *hv_clock;

static struct pvclock_vsyscall_time_info *hv_clock;

static struct pvclock_wall_clock wall_clock;



/*
@@ -67,7 +63,7 @@ static unsigned long kvm_get_wallclock(void) 
	preempt_disable();

	cpu = smp_processor_id();



	vcpu_time = &hv_clock[cpu].clock;

	vcpu_time = &hv_clock[cpu].pvti;

	pvclock_read_wallclock(&wall_clock, vcpu_time, &ts);



	preempt_enable();
@@ -88,7 +84,7 @@ static cycle_t kvm_clock_read(void) 


	preempt_disable_notrace();

	cpu = smp_processor_id();

	src = &hv_clock[cpu].clock;

	src = &hv_clock[cpu].pvti;

	ret = pvclock_clocksource_read(src);

	preempt_enable_notrace();

	return ret;
@@ -116,7 +112,7 @@ static unsigned long kvm_get_tsc_khz(void) 


	preempt_disable();

	cpu = smp_processor_id();

	src = &hv_clock[cpu].clock;

	src = &hv_clock[cpu].pvti;

	tsc_khz = pvclock_tsc_khz(src);

	preempt_enable();

	return tsc_khz;
@@ -143,7 +139,7 @@ bool kvm_check_and_clear_guest_paused(void) 
	if (!hv_clock)

		return ret;



	src = &hv_clock[cpu].clock;

	src = &hv_clock[cpu].pvti;

	if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {

		src->flags &= ~PVCLOCK_GUEST_STOPPED;

		ret = true;
@@ -164,7 +160,7 @@ int kvm_register_clock(char *txt) 
{

	int cpu = smp_processor_id();

	int low, high, ret;

	struct pvclock_vcpu_time_info *src = &hv_clock[cpu].clock;

	struct pvclock_vcpu_time_info *src = &hv_clock[cpu].pvti;



	low = (int)__pa(src) | 1;

	high = ((u64)__pa(src) >> 32);
@@ -235,7 +231,7 @@ void __init kvmclock_init(void) 
	printk(KERN_INFO "kvm-clock: Using msrs %x and %x",

		msr_kvm_system_time, msr_kvm_wall_clock);



	mem = memblock_alloc(sizeof(struct pvclock_aligned_vcpu_time_info) * NR_CPUS,

	mem = memblock_alloc(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS,

			     PAGE_SIZE);

	if (!mem)

		return;
@@ -244,7 +240,7 @@ void __init kvmclock_init(void) 
	if (kvm_register_clock("boot clock")) {

		hv_clock = NULL;

		memblock_free(mem,

			sizeof(struct pvclock_aligned_vcpu_time_info)*NR_CPUS);

			sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS);

		return;

	}

	pv_time_ops.sched_clock = kvm_clock_read;
@@ -269,3 +265,37 @@ void __init kvmclock_init(void) 
	if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))

		pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);

}



int __init kvm_setup_vsyscall_timeinfo(void)

{

#ifdef CONFIG_X86_64

	int cpu;

	int ret;

	u8 flags;

	struct pvclock_vcpu_time_info *vcpu_time;

	unsigned int size;



	size = sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS;



	preempt_disable();

	cpu = smp_processor_id();



	vcpu_time = &hv_clock[cpu].pvti;

	flags = pvclock_read_flags(vcpu_time);



	if (!(flags & PVCLOCK_TSC_STABLE_BIT)) {

		preempt_enable();

		return 1;

	}



	if ((ret = pvclock_init_vsyscall(hv_clock, size))) {

		preempt_enable();

		return ret;

	}



	preempt_enable();



	kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;

#endif

	return 0;

}