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| author | Keir Fraser <keir.fraser@citrix.com> | 2008-05-24 09:27:03 +0100 |
|---|---|---|
| committer | Keir Fraser <keir.fraser@citrix.com> | 2008-05-24 09:27:03 +0100 |
| commit | e1845bbe732b5ad5755f0f3a93fb6ea85919e8a2 (patch) | |
| tree | fbdbe843c34d11b19ffc3fef6c6304103a1e7bc3 /xen/arch/x86/hvm/hpet.c | |
| parent | d0f28d825eafe00591d7b80b8de26e4fd783d924 (diff) | |
| download | xen-e1845bbe732b5ad5755f0f3a93fb6ea85919e8a2.tar.gz xen-e1845bbe732b5ad5755f0f3a93fb6ea85919e8a2.tar.bz2 xen-e1845bbe732b5ad5755f0f3a93fb6ea85919e8a2.zip | |
hvm: Build guest timers on monotonic system time.
Move hvm platform timers from underlying physical CPU TSC to Xen
system time and ensure domain-wide monotonicity. TSC on many systems
may skew between processors leading to 'time going backwards' messages
from some guests.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
Diffstat (limited to 'xen/arch/x86/hvm/hpet.c')
| -rw-r--r-- | xen/arch/x86/hvm/hpet.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c index 3b9f84250a..e8a83949f1 100644 --- a/xen/arch/x86/hvm/hpet.c +++ b/xen/arch/x86/hvm/hpet.c @@ -29,9 +29,9 @@ #define S_TO_NS 1000000000ULL /* 1s = 10^9 ns */ #define S_TO_FS 1000000000000000ULL /* 1s = 10^15 fs */ -/* Frequency_of_TSC / frequency_of_HPET = 32 */ -#define TSC_PER_HPET_TICK 32 -#define guest_time_hpet(v) (hvm_get_guest_time(v) / TSC_PER_HPET_TICK) +/* Frequency_of_Xen_systeme_time / frequency_of_HPET = 16 */ +#define STIME_PER_HPET_TICK 16 +#define guest_time_hpet(v) (hvm_get_guest_time(v) / STIME_PER_HPET_TICK) #define HPET_ID 0x000 #define HPET_PERIOD 0x004 @@ -192,7 +192,7 @@ static void hpet_stop_timer(HPETState *h, unsigned int tn) /* the number of HPET tick that stands for * 1/(2^10) second, namely, 0.9765625 milliseconds */ -#define HPET_TINY_TIME_SPAN ((h->tsc_freq >> 10) / TSC_PER_HPET_TICK) +#define HPET_TINY_TIME_SPAN ((h->stime_freq >> 10) / STIME_PER_HPET_TICK) static void hpet_set_timer(HPETState *h, unsigned int tn) { @@ -558,17 +558,17 @@ void hpet_init(struct vcpu *v) spin_lock_init(&h->lock); h->vcpu = v; - h->tsc_freq = ticks_per_sec(v); + h->stime_freq = S_TO_NS; - h->hpet_to_ns_scale = ((S_TO_NS * TSC_PER_HPET_TICK) << 10) / h->tsc_freq; + h->hpet_to_ns_scale = ((S_TO_NS * STIME_PER_HPET_TICK) << 10) / h->stime_freq; h->hpet_to_ns_limit = ~0ULL / h->hpet_to_ns_scale; /* 64-bit main counter; 3 timers supported; LegacyReplacementRoute. */ h->hpet.capability = 0x8086A201ULL; /* This is the number of femptoseconds per HPET tick. */ - /* Here we define HPET's frequency to be 1/32 of the TSC's */ - h->hpet.capability |= ((S_TO_FS*TSC_PER_HPET_TICK/h->tsc_freq) << 32); + /* Here we define HPET's frequency to be 1/16 of Xen system time */ + h->hpet.capability |= ((S_TO_FS*STIME_PER_HPET_TICK/h->stime_freq) << 32); for ( i = 0; i < HPET_TIMER_NUM; i++ ) { |