diff options
Diffstat (limited to 'arch/x86/include/asm/pvclock.h')
| -rw-r--r-- | arch/x86/include/asm/pvclock.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index c59cc97fe6c1..109a9dd5d454 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/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); +u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src); void pvclock_set_flags(u8 flags); unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); void pvclock_read_wallclock(struct pvclock_wall_clock *wall, @@ -56,4 +57,50 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) return product; } +static __always_inline +u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src) +{ + u64 delta = __native_read_tsc() - src->tsc_timestamp; + return pvclock_scale_delta(delta, src->tsc_to_system_mul, + src->tsc_shift); +} + +static __always_inline +unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, + cycle_t *cycles, u8 *flags) +{ + unsigned version; + cycle_t ret, offset; + u8 ret_flags; + + version = src->version; + /* Note: emulated platforms which do not advertise SSE2 support + * result in kvmclock not using the necessary RDTSC barriers. + * Without barriers, it is possible that RDTSC instruction reads from + * the time stamp counter outside rdtsc_barrier protected section + * below, resulting in violation of monotonicity. + */ + rdtsc_barrier(); + offset = pvclock_get_nsec_offset(src); + ret = src->system_time + offset; + ret_flags = src->flags; + rdtsc_barrier(); + + *cycles = ret; + *flags = ret_flags; + return version; +} + +struct pvclock_vsyscall_time_info { + struct pvclock_vcpu_time_info pvti; + u32 migrate_count; +} __attribute__((__aligned__(SMP_CACHE_BYTES))); + +#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info) +#define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1) + +int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i, + int size); +struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu); + #endif /* _ASM_X86_PVCLOCK_H */ |