diff options
| -rw-r--r-- | arch/x86/include/asm/vdso/gettimeofday.h | 10 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 | ||||
| -rw-r--r-- | drivers/clocksource/hyperv_timer.c | 16 | ||||
| -rw-r--r-- | include/clocksource/hyperv_timer.h | 24 |
4 files changed, 29 insertions, 28 deletions
diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h index 0badf0a9f03d..c81858d903dc 100644 --- a/arch/x86/include/asm/vdso/gettimeofday.h +++ b/arch/x86/include/asm/vdso/gettimeofday.h @@ -238,10 +238,12 @@ static u64 vread_pvclock(void) #ifdef CONFIG_HYPERV_TIMER static u64 vread_hvclock(void) { - u64 ret = hv_read_tsc_page(&hvclock_page); - if (likely(ret != U64_MAX)) - ret &= S64_MAX; - return ret; + u64 tsc, time; + + if (hv_read_tsc_page_tsc(&hvclock_page, &tsc, &time)) + return time & S64_MAX; + + return U64_MAX; } #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ceb7c5e9cf9e..99d97ba6104f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2799,14 +2799,13 @@ static u64 read_tsc(void) static inline u64 vgettsc(struct pvclock_clock *clock, u64 *tsc_timestamp, int *mode) { - long v; u64 tsc_pg_val; + long v; switch (clock->vclock_mode) { case VDSO_CLOCKMODE_HVCLOCK: - tsc_pg_val = hv_read_tsc_page_tsc(hv_get_tsc_page(), - tsc_timestamp); - if (tsc_pg_val != U64_MAX) { + if (hv_read_tsc_page_tsc(hv_get_tsc_page(), + tsc_timestamp, &tsc_pg_val)) { /* TSC page valid */ *mode = VDSO_CLOCKMODE_HVCLOCK; v = (tsc_pg_val - clock->cycle_last) & diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index bcd9042a0c9f..c643bfe2f3d4 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -393,14 +393,20 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void) } EXPORT_SYMBOL_GPL(hv_get_tsc_page); -static u64 notrace read_hv_clock_tsc(void) +static notrace u64 read_hv_clock_tsc(void) { - u64 current_tick = hv_read_tsc_page(hv_get_tsc_page()); + u64 cur_tsc, time; - if (current_tick == U64_MAX) - current_tick = hv_get_register(HV_REGISTER_TIME_REF_COUNT); + /* + * The Hyper-V Top-Level Function Spec (TLFS), section Timers, + * subsection Refererence Counter, guarantees that the TSC and MSR + * times are in sync and monotonic. Therefore we can fall back + * to the MSR in case the TSC page indicates unavailability. + */ + if (!hv_read_tsc_page_tsc(tsc_page, &cur_tsc, &time)) + time = hv_get_register(HV_REGISTER_TIME_REF_COUNT); - return current_tick; + return time; } static u64 notrace read_hv_clock_tsc_cs(struct clocksource *arg) diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h index 536f897375d0..6cdc873ac907 100644 --- a/include/clocksource/hyperv_timer.h +++ b/include/clocksource/hyperv_timer.h @@ -38,8 +38,9 @@ extern void hv_remap_tsc_clocksource(void); extern unsigned long hv_get_tsc_pfn(void); extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void); -static inline notrace u64 -hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc) +static __always_inline bool +hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, + u64 *cur_tsc, u64 *time) { u64 scale, offset; u32 sequence; @@ -63,7 +64,7 @@ hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc) do { sequence = READ_ONCE(tsc_pg->tsc_sequence); if (!sequence) - return U64_MAX; + return false; /* * Make sure we read sequence before we read other values from * TSC page. @@ -82,15 +83,8 @@ hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc) } while (READ_ONCE(tsc_pg->tsc_sequence) != sequence); - return mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; -} - -static inline notrace u64 -hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg) -{ - u64 cur_tsc; - - return hv_read_tsc_page_tsc(tsc_pg, &cur_tsc); + *time = mul_u64_u64_shr(*cur_tsc, scale, 64) + offset; + return true; } #else /* CONFIG_HYPERV_TIMER */ @@ -104,10 +98,10 @@ static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void) return NULL; } -static inline u64 hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, - u64 *cur_tsc) +static __always_inline bool +hv_read_tsc_page_tsc(const struct ms_hyperv_tsc_page *tsc_pg, u64 *cur_tsc, u64 *time) { - return U64_MAX; + return false; } static inline int hv_stimer_cleanup(unsigned int cpu) { return 0; } |