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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: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Marcelo Tosatti 2012-11-27 23:28:56 -02:00
parent 71056ae22d
commit 3dc4f7cfb7
3 changed files with 61 additions and 12 deletions
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6
arch/x86/include/asm/kvm_guest.h Normal file
View File

@ -0,0 +1,6 @@
#ifndef _ASM_X86_KVM_GUEST_H
#define _ASM_X86_KVM_GUEST_H
int kvm_setup_vsyscall_timeinfo(void);
#endif /* _ASM_X86_KVM_GUEST_H */

13
arch/x86/kernel/kvm.c
View File

@ -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);

54
arch/x86/kernel/kvmclock.c
View File

@ -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;
}