@@ -891,6 +891,16 @@ static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info *
hv_clock->tsc_to_system_mul);
}
+static inline u64 get_kernel_ns(void)
+{
+ struct timespec ts;
+
+ WARN_ON(preemptible());
+ ktime_get_ts(&ts);
+ monotonic_to_bootbased(&ts);
+ return timespec_to_ns(&ts);
+}
+
static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
static inline int kvm_tsc_changes_freq(void)
@@ -902,6 +912,15 @@ static inline int kvm_tsc_changes_freq(void)
return ret;
}
+static inline u64 nsec_to_cycles(u64 nsec)
+{
+ WARN_ON(preemptible());
+ if (kvm_tsc_changes_freq())
+ printk_once(KERN_WARNING
+ "kvm: unreliable cycle conversion on adjustable rate TSC\n");
+ return (nsec * __get_cpu_var(cpu_tsc_khz)) / USEC_PER_SEC;
+}
+
void guest_write_tsc(struct kvm_vcpu *vcpu, u64 data)
{
struct kvm *kvm = vcpu->kvm;
@@ -910,9 +929,7 @@ void guest_write_tsc(struct kvm_vcpu *vcpu, u64 data)
spin_lock(&kvm->arch.tsc_write_lock);
offset = data - native_read_tsc();
- ktime_get_ts(&ts);
- monotonic_to_bootbased(&ts);
- ns = timespec_to_ns(&ts);
+ ns = get_kernel_ns();
elapsed = ns - kvm->arch.last_tsc_nsec;
/*
@@ -928,10 +945,9 @@ void guest_write_tsc(struct kvm_vcpu *vcpu, u64 data)
offset = kvm->arch.last_tsc_offset;
pr_debug("kvm: matched tsc offset for %llu\n", data);
} else {
- u64 tsc_delta = elapsed * __get_cpu_var(cpu_tsc_khz);
- tsc_delta = tsc_delta / USEC_PER_SEC;
- offset += tsc_delta;
- pr_debug("kvm: adjusted tsc offset by %llu\n", tsc_delta);
+ u64 delta = nsec_to_cycles(elapsed);
+ offset += delta;
+ pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
}
ns = kvm->arch.last_tsc_nsec;
}
@@ -948,11 +964,11 @@ EXPORT_SYMBOL_GPL(guest_write_tsc);
static int kvm_write_guest_time(struct kvm_vcpu *v)
{
- struct timespec ts;
unsigned long flags;
struct kvm_vcpu_arch *vcpu = &v->arch;
void *shared_kaddr;
unsigned long this_tsc_khz;
+ s64 kernel_ns;
if ((!vcpu->time_page))
return 0;
@@ -960,8 +976,7 @@ static int kvm_write_guest_time(struct kvm_vcpu *v)
/* Keep irq disabled to prevent changes to the clock */
local_irq_save(flags);
kvm_get_msr(v, MSR_IA32_TSC, &vcpu->hv_clock.tsc_timestamp);
- ktime_get_ts(&ts);
- monotonic_to_bootbased(&ts);
+ kernel_ns = get_kernel_ns();
this_tsc_khz = __get_cpu_var(cpu_tsc_khz);
local_irq_restore(flags);
@@ -976,9 +991,7 @@ static int kvm_write_guest_time(struct kvm_vcpu *v)
}
/* With all the info we got, fill in the values */
- vcpu->hv_clock.system_time = ts.tv_nsec +
- (NSEC_PER_SEC * (u64)ts.tv_sec) + v->kvm->arch.kvmclock_offset;
-
+ vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
vcpu->hv_clock.flags = 0;
/*
@@ -3261,7 +3274,6 @@ long kvm_arch_vm_ioctl(struct file *filp,
break;
}
case KVM_SET_CLOCK: {
- struct timespec now;
struct kvm_clock_data user_ns;
u64 now_ns;
s64 delta;
@@ -3275,19 +3287,16 @@ long kvm_arch_vm_ioctl(struct file *filp,
goto out;
r = 0;
- ktime_get_ts(&now);
- now_ns = timespec_to_ns(&now);
+ now_ns = get_kernel_ns();
delta = user_ns.clock - now_ns;
kvm->arch.kvmclock_offset = delta;
break;
}
case KVM_GET_CLOCK: {
- struct timespec now;
struct kvm_clock_data user_ns;
u64 now_ns;
- ktime_get_ts(&now);
- now_ns = timespec_to_ns(&now);
+ now_ns = get_kernel_ns();
user_ns.clock = kvm->arch.kvmclock_offset + now_ns;
user_ns.flags = 0;