summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/pvclock.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/pvclock.c')
-rw-r--r--arch/x86/kernel/pvclock.c143
1 files changed, 91 insertions, 52 deletions
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 42eb3300dfc6..85c39590c1a4 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -17,23 +17,13 @@
#include <linux/kernel.h>
#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/sched.h>
+#include <linux/gfp.h>
+#include <linux/bootmem.h>
+#include <asm/fixmap.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;
- u8 flags;
-};
-
static u8 valid_flags __read_mostly = 0;
void pvclock_set_flags(u8 flags)
@@ -41,34 +31,6 @@ void pvclock_set_flags(u8 flags)
valid_flags = flags;
}
-static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow)
-{
- u64 delta = native_read_tsc() - shadow->tsc_timestamp;
- return pvclock_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;
- dst->flags = src->flags;
- rmb(); /* test version after fetching data */
- } while ((src->version & 1) || (dst->version != src->version));
-
- return dst->version;
-}
-
unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
{
u64 pv_tsc_khz = 1000000ULL << 32;
@@ -88,23 +50,32 @@ void pvclock_resume(void)
atomic64_set(&last_value, 0);
}
+u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src)
+{
+ unsigned version;
+ cycle_t ret;
+ u8 flags;
+
+ do {
+ version = __pvclock_read_cycles(src, &ret, &flags);
+ } while ((src->version & 1) || version != src->version);
+
+ return flags & valid_flags;
+}
+
cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
{
- struct pvclock_shadow_time shadow;
unsigned version;
- cycle_t ret, offset;
+ cycle_t ret;
u64 last;
+ u8 flags;
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);
+ version = __pvclock_read_cycles(src, &ret, &flags);
+ } while ((src->version & 1) || version != src->version);
if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) &&
- (shadow.flags & PVCLOCK_TSC_STABLE_BIT))
+ (flags & PVCLOCK_TSC_STABLE_BIT))
return ret;
/*
@@ -156,3 +127,71 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock,
set_normalized_timespec(ts, now.tv_sec, now.tv_nsec);
}
+
+static struct pvclock_vsyscall_time_info *pvclock_vdso_info;
+
+static struct pvclock_vsyscall_time_info *
+pvclock_get_vsyscall_user_time_info(int cpu)
+{
+ if (!pvclock_vdso_info) {
+ BUG();
+ return NULL;
+ }
+
+ return &pvclock_vdso_info[cpu];
+}
+
+struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu)
+{
+ return &pvclock_get_vsyscall_user_time_info(cpu)->pvti;
+}
+
+#ifdef CONFIG_X86_64
+static int pvclock_task_migrate(struct notifier_block *nb, unsigned long l,
+ void *v)
+{
+ struct task_migration_notifier *mn = v;
+ struct pvclock_vsyscall_time_info *pvti;
+
+ pvti = pvclock_get_vsyscall_user_time_info(mn->from_cpu);
+
+ /* this is NULL when pvclock vsyscall is not initialized */
+ if (unlikely(pvti == NULL))
+ return NOTIFY_DONE;
+
+ pvti->migrate_count++;
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block pvclock_migrate = {
+ .notifier_call = pvclock_task_migrate,
+};
+
+/*
+ * Initialize the generic pvclock vsyscall state. This will allocate
+ * a/some page(s) for the per-vcpu pvclock information, set up a
+ * fixmap mapping for the page(s)
+ */
+
+int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
+ int size)
+{
+ int idx;
+
+ WARN_ON (size != PVCLOCK_VSYSCALL_NR_PAGES*PAGE_SIZE);
+
+ pvclock_vdso_info = i;
+
+ for (idx = 0; idx <= (PVCLOCK_FIXMAP_END-PVCLOCK_FIXMAP_BEGIN); idx++) {
+ __set_fixmap(PVCLOCK_FIXMAP_BEGIN + idx,
+ __pa_symbol(i) + (idx*PAGE_SIZE),
+ PAGE_KERNEL_VVAR);
+ }
+
+
+ register_task_migration_notifier(&pvclock_migrate);
+
+ return 0;
+}
+#endif
OpenPOWER on IntegriCloud