LXR linux/arch/x86/include/asm/pvclock-abi.h

   1#ifndef _ASM_X86_PVCLOCK_ABI_H
   2#define _ASM_X86_PVCLOCK_ABI_H
   3#ifndef __ASSEMBLY__
   4
   5/*
   6 * These structs MUST NOT be changed.
   7 * They are the ABI between hypervisor and guest OS.
   8 * Both Xen and KVM are using this.
   9 *
  10 * pvclock_vcpu_time_info holds the system time and the tsc timestamp
  11 * of the last update. So the guest can use the tsc delta to get a
  12 * more precise system time.  There is one per virtual cpu.
  13 *
  14 * pvclock_wall_clock references the point in time when the system
  15 * time was zero (usually boot time), thus the guest calculates the
  16 * current wall clock by adding the system time.
  17 *
  18 * Protocol for the "version" fields is: hypervisor raises it (making
  19 * it uneven) before it starts updating the fields and raises it again
  20 * (making it even) when it is done.  Thus the guest can make sure the
  21 * time values it got are consistent by checking the version before
  22 * and after reading them.
  23 */
  24
  25struct pvclock_vcpu_time_info {
  26        u32   version;
  27        u32   pad0;
  28        u64   tsc_timestamp;
  29        u64   system_time;
  30        u32   tsc_to_system_mul;
  31        s8    tsc_shift;
  32        u8    pad[3];
  33} __attribute__((__packed__)); /* 32 bytes */
  34
  35struct pvclock_wall_clock {
  36        u32   version;
  37        u32   sec;
  38        u32   nsec;
  39} __attribute__((__packed__));
  40
  41#endif /* __ASSEMBLY__ */
  42#endif /* _ASM_X86_PVCLOCK_ABI_H */
  43