[12/17] Add helper function get_kernel_ns

Commit Message

Zachary Amsden June 15, 2010, 7:34 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 703ea43..15c7317 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -915,6 +915,16 @@  static void kvm_get_time_scale(uint32_t scaled_khz, uint32_t base_khz,
 		 __func__, base_khz, scaled_khz, shift, *pmultiplier);
 }
 
+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 void kvm_request_guest_time_update(struct kvm_vcpu *v)
@@ -924,7 +934,6 @@  static inline void kvm_request_guest_time_update(struct kvm_vcpu *v)
 
 static int kvm_recompute_guest_time(struct kvm_vcpu *v)
 {
-	struct timespec ts;
 	unsigned long flags;
 	struct kvm_vcpu_arch *vcpu = &v->arch;
 	void *shared_kaddr;
@@ -944,9 +953,7 @@  static int kvm_recompute_guest_time(struct kvm_vcpu *v)
 	local_irq_save(flags);
 	this_tsc_khz = __get_cpu_var(cpu_tsc_khz);
 	kvm_get_msr(v, MSR_IA32_TSC, &tsc_timestamp);
-	ktime_get_ts(&ts);
-	monotonic_to_bootbased(&ts);
-	kernel_ns = timespec_to_ns(&ts);
+	kernel_ns = get_kernel_ns();
 	local_irq_restore(flags);
 
 	if (unlikely(this_tsc_khz == 0)) {
@@ -1865,11 +1872,7 @@  void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 		/* Subtract elapsed cycle time from the delta computation */
 		if (check_tsc_unstable() && vcpu->arch.last_host_ns) {
-			s64 delta;
-			struct timespec ts;
-			ktime_get_ts(&ts);
-			monotonic_to_bootbased(&ts);
-			delta = timespec_to_ns(&ts) - vcpu->arch.last_host_ns;
+			s64 delta = get_kernel_ns() - vcpu->arch.last_host_ns;
 			delta = delta * per_cpu(cpu_tsc_khz, cpu);
 			delta = delta / USEC_PER_SEC;
 			tsc_delta -= delta;
@@ -1898,10 +1901,7 @@  void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 	 * vcpu->cpu = -1 to force the recalibration above.
 	 */
 	if (check_tsc_unstable()) {
-		struct timespec ts;
-		ktime_get_ts(&ts);
-		monotonic_to_bootbased(&ts);
-		vcpu->arch.last_host_ns = timespec_to_ns(&ts);
+		vcpu->arch.last_host_ns = get_kernel_ns();
 		vcpu->cpu = -1;
 	}
 }