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d63285e94a
Implement reset of kernel watchdogs at pvclock read time. This avoids adding special code to every watchdog. This is possible for watchdogs which measure time based on sched_clock() or ktime_get() variants. Suggested by Don Zickus. Acked-by: Don Zickus <dzickus@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
108 lines
2.8 KiB
C
108 lines
2.8 KiB
C
#ifndef _ASM_X86_PVCLOCK_H
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#define _ASM_X86_PVCLOCK_H
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#include <linux/clocksource.h>
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#include <asm/pvclock-abi.h>
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/* some helper functions for xen and kvm pv clock sources */
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cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
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u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
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void pvclock_set_flags(u8 flags);
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unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
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void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
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struct pvclock_vcpu_time_info *vcpu,
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struct timespec *ts);
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void pvclock_resume(void);
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void pvclock_touch_watchdogs(void);
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/*
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* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
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* yielding a 64-bit result.
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*/
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static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
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{
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u64 product;
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#ifdef __i386__
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u32 tmp1, tmp2;
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#else
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ulong tmp;
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#endif
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if (shift < 0)
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delta >>= -shift;
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else
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delta <<= shift;
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#ifdef __i386__
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__asm__ (
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"mul %5 ; "
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"mov %4,%%eax ; "
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"mov %%edx,%4 ; "
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"mul %5 ; "
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"xor %5,%5 ; "
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"add %4,%%eax ; "
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"adc %5,%%edx ; "
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: "=A" (product), "=r" (tmp1), "=r" (tmp2)
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: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
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#elif defined(__x86_64__)
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__asm__ (
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"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
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: [lo]"=a"(product),
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[hi]"=d"(tmp)
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: "0"(delta),
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[mul_frac]"rm"((u64)mul_frac));
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#else
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#error implement me!
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#endif
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return product;
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}
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static __always_inline
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u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
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{
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u64 delta = __native_read_tsc() - src->tsc_timestamp;
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return pvclock_scale_delta(delta, src->tsc_to_system_mul,
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src->tsc_shift);
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}
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static __always_inline
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unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
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cycle_t *cycles, u8 *flags)
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{
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unsigned version;
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cycle_t ret, offset;
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u8 ret_flags;
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version = src->version;
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/* Note: emulated platforms which do not advertise SSE2 support
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* result in kvmclock not using the necessary RDTSC barriers.
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* Without barriers, it is possible that RDTSC instruction reads from
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* the time stamp counter outside rdtsc_barrier protected section
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* below, resulting in violation of monotonicity.
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*/
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rdtsc_barrier();
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offset = pvclock_get_nsec_offset(src);
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ret = src->system_time + offset;
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ret_flags = src->flags;
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rdtsc_barrier();
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*cycles = ret;
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*flags = ret_flags;
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return version;
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}
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struct pvclock_vsyscall_time_info {
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struct pvclock_vcpu_time_info pvti;
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} __attribute__((__aligned__(SMP_CACHE_BYTES)));
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#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
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#define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1)
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int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
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int size);
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struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu);
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#endif /* _ASM_X86_PVCLOCK_H */
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