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x86: pvclock: remove pvclock_shadow_time 

Originally from Jeremy Fitzhardinge.

We can copy the information directly from "struct pvclock_vcpu_time_info",
remove pvclock_shadow_time.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Marcelo Tosatti 2012-11-27 23:28:50 -02:00
parent b01578de45
commit 42b5637d69
1 changed files with 11 additions and 46 deletions
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57
arch/x86/kernel/pvclock.c
View File

@ -19,21 +19,6 @@
#include <linux/percpu.h> #include <linux/percpu.h>
#include <asm/pvclock.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; static u8 valid_flags __read_mostly = 0;
void pvclock_set_flags(u8 flags) void pvclock_set_flags(u8 flags)
@ -41,32 +26,11 @@ void pvclock_set_flags(u8 flags)
valid_flags = flags; valid_flags = flags;
} }
static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow) static u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
{ {
u64 delta = native_read_tsc() - shadow->tsc_timestamp; u64 delta = native_read_tsc() - src->tsc_timestamp;
return pvclock_scale_delta(delta, shadow->tsc_to_nsec_mul, return pvclock_scale_delta(delta, src->tsc_to_system_mul,
shadow->tsc_shift); src->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) unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
@ -90,21 +54,22 @@ void pvclock_resume(void)
cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
{ {
struct pvclock_shadow_time shadow;
unsigned version; unsigned version;
cycle_t ret, offset; cycle_t ret, offset;
u64 last; u64 last;
u8 flags;
do { do {
version = pvclock_get_time_values(&shadow, src); version = src->version;
rdtsc_barrier(); rdtsc_barrier();
offset = pvclock_get_nsec_offset(&shadow); offset = pvclock_get_nsec_offset(src);
ret = shadow.system_timestamp + offset; ret = src->system_time + offset;
flags = src->flags;
rdtsc_barrier(); rdtsc_barrier();
} while (version != src->version); } while ((src->version & 1) || version != src->version);
if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) && if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) &&
(shadow.flags & PVCLOCK_TSC_STABLE_BIT)) (flags & PVCLOCK_TSC_STABLE_BIT))
return ret; return ret;
/* /*