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-rw-r--r--arch/x86/kernel/Makefile1
-rw-r--r--arch/x86/kernel/kvmclock.c89
-rw-r--r--arch/x86/kernel/pvclock.c141
3 files changed, 175 insertions, 56 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 5e618c3b4720..77807d4769c9 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_VMI) += vmi_32.o vmiclock_32.o
obj-$(CONFIG_KVM_GUEST) += kvm.o
obj-$(CONFIG_KVM_CLOCK) += kvmclock.o
obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch_$(BITS).o
+obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o
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;
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
new file mode 100644
index 000000000000..05fbe9a0325a
--- /dev/null
+++ b/arch/x86/kernel/pvclock.c
@@ -0,0 +1,141 @@
+/* paravirtual clock -- common code used by kvm/xen
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <asm/pvclock.h>
+
+/*
+ * These are perodically updated
+ * xen: magic shared_info page
+ * kvm: gpa registered via msr
+ * and then copied here.
+ */
+struct pvclock_shadow_time {
+ u64 tsc_timestamp; /* TSC at last update of time vals. */
+ u64 system_timestamp; /* Time, in nanosecs, since boot. */
+ u32 tsc_to_nsec_mul;
+ int tsc_shift;
+ u32 version;
+};
+
+/*
+ * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
+ * yielding a 64-bit result.
+ */
+static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
+{
+ u64 product;
+#ifdef __i386__
+ u32 tmp1, tmp2;
+#endif
+
+ if (shift < 0)
+ delta >>= -shift;
+ else
+ delta <<= shift;
+
+#ifdef __i386__
+ __asm__ (
+ "mul %5 ; "
+ "mov %4,%%eax ; "
+ "mov %%edx,%4 ; "
+ "mul %5 ; "
+ "xor %5,%5 ; "
+ "add %4,%%eax ; "
+ "adc %5,%%edx ; "
+ : "=A" (product), "=r" (tmp1), "=r" (tmp2)
+ : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
+#elif __x86_64__
+ __asm__ (
+ "mul %%rdx ; shrd $32,%%rdx,%%rax"
+ : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
+#else
+#error implement me!
+#endif
+
+ return product;
+}
+
+static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow)
+{
+ u64 delta = native_read_tsc() - shadow->tsc_timestamp;
+ return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
+}
+
+/*
+ * Reads a consistent set of time-base values from hypervisor,
+ * into a shadow data area.
+ */
+static unsigned pvclock_get_time_values(struct pvclock_shadow_time *dst,
+ struct pvclock_vcpu_time_info *src)
+{
+ do {
+ dst->version = src->version;
+ rmb(); /* fetch version before data */
+ dst->tsc_timestamp = src->tsc_timestamp;
+ dst->system_timestamp = src->system_time;
+ dst->tsc_to_nsec_mul = src->tsc_to_system_mul;
+ dst->tsc_shift = src->tsc_shift;
+ rmb(); /* test version after fetching data */
+ } while ((src->version & 1) || (dst->version != src->version));
+
+ return dst->version;
+}
+
+cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
+{
+ struct pvclock_shadow_time shadow;
+ unsigned version;
+ cycle_t ret, offset;
+
+ do {
+ version = pvclock_get_time_values(&shadow, src);
+ barrier();
+ offset = pvclock_get_nsec_offset(&shadow);
+ ret = shadow.system_timestamp + offset;
+ barrier();
+ } while (version != src->version);
+
+ return ret;
+}
+
+void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock,
+ struct pvclock_vcpu_time_info *vcpu_time,
+ struct timespec *ts)
+{
+ u32 version;
+ u64 delta;
+ struct timespec now;
+
+ /* get wallclock at system boot */
+ do {
+ version = wall_clock->version;
+ rmb(); /* fetch version before time */
+ now.tv_sec = wall_clock->sec;
+ now.tv_nsec = wall_clock->nsec;
+ rmb(); /* fetch time before checking version */
+ } while ((wall_clock->version & 1) || (version != wall_clock->version));
+
+ delta = pvclock_clocksource_read(vcpu_time); /* time since system boot */
+ delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec;
+
+ now.tv_nsec = do_div(delta, NSEC_PER_SEC);
+ now.tv_sec = delta;
+
+ set_normalized_timespec(ts, now.tv_sec, now.tv_nsec);
+}