x86: paravirt: factor out cpu_khz to common code

KVM intends to use paravirt code to calibrate khz. Xen
current code will do just fine. So as a first step, factor out
code to pvclock.c.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

3 files changed, 15 insertions, 9 deletions

diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 05fbe9a0325a..1c54b5fb7aed 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -97,6 +97,18 @@ static unsigned pvclock_get_time_values(struct pvclock_shadow_time *dst,
         return dst->version;
 }
 
+unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
+{
+        u64 tsc_khz = 1000000ULL << 32;
+
+        do_div(tsc_khz, src->tsc_to_system_mul);
+        if (src->tsc_shift < 0)
+                tsc_khz <<= -src->tsc_shift;
+        else
+                tsc_khz >>= src->tsc_shift;
+        return tsc_khz;
+}
+
 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
 {
         struct pvclock_shadow_time shadow;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 004ba86326ae..c9f7cda48ed7 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -198,17 +198,10 @@ unsigned long long xen_sched_clock(void)
 /* Get the TSC speed from Xen */
 unsigned long xen_tsc_khz(void)
 {
-        u64 xen_khz = 1000000ULL << 32;
-        const struct pvclock_vcpu_time_info *info =
+        struct pvclock_vcpu_time_info *info =
                 &HYPERVISOR_shared_info->vcpu_info[0].time;
 
-        do_div(xen_khz, info->tsc_to_system_mul);
-        if (info->tsc_shift < 0)
-                xen_khz <<= -info->tsc_shift;
-        else
-                xen_khz >>= info->tsc_shift;
-
-        return xen_khz;
+        return pvclock_tsc_khz(info);
 }
 
 cycle_t xen_clocksource_read(void)
diff --git a/include/asm-x86/pvclock.h b/include/asm-x86/pvclock.h
index 1a38f6834800..ad29e277fd6d 100644
--- a/include/asm-x86/pvclock.h
+++ b/include/asm-x86/pvclock.h
@@ -6,6 +6,7 @@
 
 /* some helper functions for xen and kvm pv clock sources */
 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
+unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
                             struct pvclock_vcpu_time_info *vcpu,
                             struct timespec *ts);