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authorGerd Hoffmann <kraxel@redhat.com>2008-06-03 16:17:30 +0200
committerAvi Kivity <avi@qumranet.com>2008-06-24 21:02:32 +0300
commit1c7b67f7576c4ca2a344379a4a29eec8fe8e7935 (patch)
treea6d6150ba4109775ed7c2e928e0ffefaa29f13e8
parent7af192c954017499ec163bc9dbaaee2e593d7ef2 (diff)
x86: Make xen use the paravirt clocksource structs and functions
This patch updates the xen guest to use the pvclock structs and helper functions. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
-rw-r--r--arch/x86/xen/Kconfig1
-rw-r--r--arch/x86/xen/time.c132
-rw-r--r--include/xen/interface/xen.h7
3 files changed, 16 insertions, 124 deletions
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 2e641be2737e..3a4f16aea4bf 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -5,6 +5,7 @@
config XEN
bool "Xen guest support"
select PARAVIRT
+ select PARAVIRT_CLOCK
depends on X86_32
depends on X86_CMPXCHG && X86_TSC && !(X86_VISWS || X86_VOYAGER)
help
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 52b2e3856980..41e217503c96 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -14,6 +14,7 @@
#include <linux/kernel_stat.h>
#include <linux/math64.h>
+#include <asm/pvclock.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
@@ -31,17 +32,6 @@
static cycle_t xen_clocksource_read(void);
-/* These are perodically updated in shared_info, and then copied here. */
-struct shadow_time_info {
- 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;
-};
-
-static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
-
/* runstate info updated by Xen */
static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
@@ -211,7 +201,7 @@ unsigned long long xen_sched_clock(void)
unsigned long xen_cpu_khz(void)
{
u64 xen_khz = 1000000ULL << 32;
- const struct vcpu_time_info *info =
+ const struct pvclock_vcpu_time_info *info =
&HYPERVISOR_shared_info->vcpu_info[0].time;
do_div(xen_khz, info->tsc_to_system_mul);
@@ -223,121 +213,26 @@ unsigned long xen_cpu_khz(void)
return xen_khz;
}
-/*
- * Reads a consistent set of time-base values from Xen, into a shadow data
- * area.
- */
-static unsigned get_time_values_from_xen(void)
-{
- struct vcpu_time_info *src;
- struct shadow_time_info *dst;
-
- /* src is shared memory with the hypervisor, so we need to
- make sure we get a consistent snapshot, even in the face of
- being preempted. */
- src = &__get_cpu_var(xen_vcpu)->time;
- dst = &__get_cpu_var(shadow_time);
-
- 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;
- rmb(); /* test version after fetching data */
- } while ((src->version & 1) | (dst->version ^ src->version));
-
- return dst->version;
-}
-
-/*
- * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
- * yielding a 64-bit result.
- */
-static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
-{
- u64 product;
-#ifdef __i386__
- u32 tmp1, tmp2;
-#endif
-
- if (shift < 0)
- delta >>= -shift;
- else
- delta <<= shift;
-
-#ifdef __i386__
- __asm__ (
- "mul %5 ; "
- "mov %4,%%eax ; "
- "mov %%edx,%4 ; "
- "mul %5 ; "
- "xor %5,%5 ; "
- "add %4,%%eax ; "
- "adc %5,%%edx ; "
- : "=A" (product), "=r" (tmp1), "=r" (tmp2)
- : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
-#elif __x86_64__
- __asm__ (
- "mul %%rdx ; shrd $32,%%rdx,%%rax"
- : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
-#else
-#error implement me!
-#endif
-
- return product;
-}
-
-static u64 get_nsec_offset(struct shadow_time_info *shadow)
-{
- u64 now, delta;
- now = native_read_tsc();
- delta = now - shadow->tsc_timestamp;
- return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
-}
-
static cycle_t xen_clocksource_read(void)
{
- struct shadow_time_info *shadow = &get_cpu_var(shadow_time);
+ struct pvclock_vcpu_time_info *src;
cycle_t ret;
- unsigned version;
-
- do {
- version = get_time_values_from_xen();
- barrier();
- ret = shadow->system_timestamp + get_nsec_offset(shadow);
- barrier();
- } while (version != __get_cpu_var(xen_vcpu)->time.version);
-
- put_cpu_var(shadow_time);
+ src = &get_cpu_var(xen_vcpu)->time;
+ ret = pvclock_clocksource_read(src);
+ put_cpu_var(xen_vcpu);
return ret;
}
static void xen_read_wallclock(struct timespec *ts)
{
- const struct shared_info *s = HYPERVISOR_shared_info;
- u32 version;
- u64 delta;
- struct timespec now;
-
- /* get wallclock at system boot */
- do {
- version = s->wc_version;
- rmb(); /* fetch version before time */
- now.tv_sec = s->wc_sec;
- now.tv_nsec = s->wc_nsec;
- rmb(); /* fetch time before checking version */
- } while ((s->wc_version & 1) | (version ^ s->wc_version));
+ struct shared_info *s = HYPERVISOR_shared_info;
+ struct pvclock_wall_clock *wall_clock = &(s->wc);
+ struct pvclock_vcpu_time_info *vcpu_time;
- delta = xen_clocksource_read(); /* time since system boot */
- delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec;
-
- now.tv_nsec = do_div(delta, NSEC_PER_SEC);
- now.tv_sec = delta;
-
- set_normalized_timespec(ts, now.tv_sec, now.tv_nsec);
+ vcpu_time = &get_cpu_var(xen_vcpu)->time;
+ pvclock_read_wallclock(wall_clock, vcpu_time, ts);
+ put_cpu_var(xen_vcpu);
}
unsigned long xen_get_wallclock(void)
@@ -345,7 +240,6 @@ unsigned long xen_get_wallclock(void)
struct timespec ts;
xen_read_wallclock(&ts);
-
return ts.tv_sec;
}
@@ -569,8 +463,6 @@ __init void xen_time_init(void)
{
int cpu = smp_processor_id();
- get_time_values_from_xen();
-
clocksource_register(&xen_clocksource);
if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) {
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index 9b018da48cf3..819a0331cda9 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -10,6 +10,7 @@
#define __XEN_PUBLIC_XEN_H__
#include <asm/xen/interface.h>
+#include <asm/pvclock-abi.h>
/*
* XEN "SYSTEM CALLS" (a.k.a. HYPERCALLS).
@@ -336,7 +337,7 @@ struct vcpu_info {
uint8_t evtchn_upcall_mask;
unsigned long evtchn_pending_sel;
struct arch_vcpu_info arch;
- struct vcpu_time_info time;
+ struct pvclock_vcpu_time_info time;
}; /* 64 bytes (x86) */
/*
@@ -384,9 +385,7 @@ struct shared_info {
* Wallclock time: updated only by control software. Guests should base
* their gettimeofday() syscall on this wallclock-base value.
*/
- uint32_t wc_version; /* Version counter: see vcpu_time_info_t. */
- uint32_t wc_sec; /* Secs 00:00:00 UTC, Jan 1, 1970. */
- uint32_t wc_nsec; /* Nsecs 00:00:00 UTC, Jan 1, 1970. */
+ struct pvclock_wall_clock wc;
struct arch_shared_info arch;

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