diff options
Diffstat (limited to 'arch/x86/include/asm/pvclock.h')
| -rw-r--r-- | arch/x86/include/asm/pvclock.h | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index 7c1c89598688..d019f0cc80ec 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -25,6 +25,24 @@ void pvclock_resume(void); void pvclock_touch_watchdogs(void); +static __always_inline +unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src) +{ + unsigned version = src->version & ~1; + /* Make sure that the version is read before the data. */ + virt_rmb(); + return version; +} + +static __always_inline +bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src, + unsigned version) +{ + /* Make sure that the version is re-read after the data. */ + virt_rmb(); + return unlikely(version != src->version); +} + /* * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, * yielding a 64-bit result. @@ -69,23 +87,12 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) } static __always_inline -unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, - cycle_t *cycles, u8 *flags) +cycle_t __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src) { - unsigned version; - cycle_t offset; - u64 delta; - - version = src->version; - /* Make the latest version visible */ - smp_rmb(); - - delta = rdtsc_ordered() - src->tsc_timestamp; - offset = pvclock_scale_delta(delta, src->tsc_to_system_mul, - src->tsc_shift); - *cycles = src->system_time + offset; - *flags = src->flags; - return version; + u64 delta = rdtsc_ordered() - src->tsc_timestamp; + cycle_t offset = pvclock_scale_delta(delta, src->tsc_to_system_mul, + src->tsc_shift); + return src->system_time + offset; } struct pvclock_vsyscall_time_info { |