2 files changed, 34 insertions, 56 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f94bca6ff47f..e0edaaa6920a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -383,6 +383,7 @@ config VMI
 config KVM_CLOCK
         bool "KVM paravirtualized clock"
         select PARAVIRT
+        select PARAVIRT_CLOCK
         depends on !(X86_VISWS || X86_VOYAGER)
         help
           Turning on this option will allow you to run a paravirtualized clock
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 08a30986d472..87edf1ceb1df 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -18,6 +18,7 @@
 
 #include <linux/clocksource.h>
 #include <linux/kvm_para.h>
+#include <asm/pvclock.h>
 #include <asm/arch_hooks.h>
 #include <asm/msr.h>
 #include <asm/apic.h>
@@ -36,18 +37,9 @@ static int parse_no_kvmclock(char *arg)
 early_param("no-kvmclock", parse_no_kvmclock);
 
 /* The hypervisor will put information about time periodically here */
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct kvm_vcpu_time_info, hv_clock);
-#define get_clock(cpu, field) per_cpu(hv_clock, cpu).field
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock);
+static struct pvclock_wall_clock wall_clock;
 
-static inline u64 kvm_get_delta(u64 last_tsc)
-{
-        int cpu = smp_processor_id();
-        u64 delta = native_read_tsc() - last_tsc;
-        return (delta * get_clock(cpu, tsc_to_system_mul)) >> KVM_SCALE;
-}
-
-static struct kvm_wall_clock wall_clock;
-static cycle_t kvm_clock_read(void);
 /*
  * The wallclock is the time of day when we booted. Since then, some time may
  * have elapsed since the hypervisor wrote the data. So we try to account for
@@ -55,64 +47,37 @@ static cycle_t kvm_clock_read(void);
  */
 static unsigned long kvm_get_wallclock(void)
 {
-        u32 wc_sec, wc_nsec;
-        u64 delta;
+        struct pvclock_vcpu_time_info *vcpu_time;
         struct timespec ts;
-        int version, nsec;
         int low, high;
 
         low = (int)__pa(&wall_clock);
         high = ((u64)__pa(&wall_clock) >> 32);
+        native_write_msr(MSR_KVM_WALL_CLOCK, low, high);
 
-        delta = kvm_clock_read();
+        vcpu_time = &get_cpu_var(hv_clock);
+        pvclock_read_wallclock(&wall_clock, vcpu_time, &ts);
+        put_cpu_var(hv_clock);
 
-        native_write_msr(MSR_KVM_WALL_CLOCK, low, high);
-        do {
-                version = wall_clock.wc_version;
-                rmb();
-                wc_sec = wall_clock.wc_sec;
-                wc_nsec = wall_clock.wc_nsec;
-                rmb();
-        } while ((wall_clock.wc_version != version) || (version & 1));
-
-        delta = kvm_clock_read() - delta;
-        delta += wc_nsec;
-        nsec = do_div(delta, NSEC_PER_SEC);
-        set_normalized_timespec(&ts, wc_sec + delta, nsec);
-        /*
-         * Of all mechanisms of time adjustment I've tested, this one
-         * was the champion!
-         */
-        return ts.tv_sec + 1;
+        return ts.tv_sec;
 }
 
 static int kvm_set_wallclock(unsigned long now)
 {
-        return 0;
+        return -1;
 }
 
-/*
- * This is our read_clock function. The host puts an tsc timestamp each time
- * it updates a new time. Without the tsc adjustment, we can have a situation
- * in which a vcpu starts to run earlier (smaller system_time), but probes
- * time later (compared to another vcpu), leading to backwards time
- */
 static cycle_t kvm_clock_read(void)
 {
-        u64 last_tsc, now;
-        int cpu;
+        struct pvclock_vcpu_time_info *src;
+        cycle_t ret;
 
-        preempt_disable();
-        cpu = smp_processor_id();
-
-        last_tsc = get_clock(cpu, tsc_timestamp);
-        now = get_clock(cpu, system_time);
-
-        now += kvm_get_delta(last_tsc);
-        preempt_enable();
-
-        return now;
+        src = &get_cpu_var(hv_clock);
+        ret = pvclock_clocksource_read(src);
+        put_cpu_var(hv_clock);
+        return ret;
 }
+
 static struct clocksource kvm_clock = {
         .name = "kvm-clock",
         .read = kvm_clock_read,
@@ -123,13 +88,14 @@ static struct clocksource kvm_clock = {
         .flags = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-static int kvm_register_clock(void)
+static int kvm_register_clock(char *txt)
 {
         int cpu = smp_processor_id();
         int low, high;
         low = (int)__pa(&per_cpu(hv_clock, cpu)) | 1;
         high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32);
-
+        printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
+               cpu, high, low, txt);
         return native_write_msr_safe(MSR_KVM_SYSTEM_TIME, low, high);
 }
 
@@ -140,12 +106,20 @@ static void kvm_setup_secondary_clock(void)
          * Now that the first cpu already had this clocksource initialized,
          * we shouldn't fail.
          */
-        WARN_ON(kvm_register_clock());
+        WARN_ON(kvm_register_clock("secondary cpu clock"));
         /* ok, done with our trickery, call native */
         setup_secondary_APIC_clock();
 }
 #endif
 
+#ifdef CONFIG_SMP
+void __init kvm_smp_prepare_boot_cpu(void)
+{
+        WARN_ON(kvm_register_clock("primary cpu clock"));
+        native_smp_prepare_boot_cpu();
+}
+#endif
+
 /*
  * After the clock is registered, the host will keep writing to the
  * registered memory location. If the guest happens to shutdown, this memory
@@ -174,7 +148,7 @@ void __init kvmclock_init(void)
                 return;
 
         if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) {
-                if (kvm_register_clock())
+                if (kvm_register_clock("boot clock"))
                         return;
                 pv_time_ops.get_wallclock = kvm_get_wallclock;
                 pv_time_ops.set_wallclock = kvm_set_wallclock;
@@ -182,6 +156,9 @@ void __init kvmclock_init(void)
 #ifdef CONFIG_X86_LOCAL_APIC
                 pv_apic_ops.setup_secondary_clock = kvm_setup_secondary_clock;
 #endif
+#ifdef CONFIG_SMP
+                smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
+#endif
                 machine_ops.shutdown  = kvm_shutdown;
 #ifdef CONFIG_KEXEC
                 machine_ops.crash_shutdown  = kvm_crash_shutdown;