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

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_PVCLOCK_ABI_H
   3 #define _ASM_X86_PVCLOCK_ABI_H
   4 #ifndef __ASSEMBLY__
   5
   6 /*
   7  * These structs MUST NOT be changed.
   8  * They are the ABI between hypervisor and guest OS.
   9  * Both Xen and KVM are using this.
  10  *
  11  * pvclock_vcpu_time_info holds the system time and the tsc timestamp
  12  * of the last update. So the guest can use the tsc delta to get a
  13  * more precise system time.  There is one per virtual cpu.
  14  *
  15  * pvclock_wall_clock references the point in time when the system
  16  * time was zero (usually boot time), thus the guest calculates the
  17  * current wall clock by adding the system time.
  18  *
  19  * Protocol for the "version" fields is: hypervisor raises it (making
  20  * it uneven) before it starts updating the fields and raises it again
  21  * (making it even) when it is done.  Thus the guest can make sure the
  22  * time values it got are consistent by checking the version before
  23  * and after reading them.
  24  */
  25
  26 struct pvclock_vcpu_time_info {
  27         u32   version;
  28         u32   pad0;
  29         u64   tsc_timestamp;
  30         u64   system_time;
  31         u32   tsc_to_system_mul;
  32         s8    tsc_shift;
  33         u8    flags;
  34         u8    pad[2];
  35 } __attribute__((__packed__)); /* 32 bytes */
  36
  37 struct pvclock_wall_clock {
  38         u32   version;
  39         u32   sec;
  40         u32   nsec;
  41 } __attribute__((__packed__));
  42
  43 #define PVCLOCK_TSC_STABLE_BIT  (1 << 0)
  44 #define PVCLOCK_GUEST_STOPPED   (1 << 1)
  45 /* PVCLOCK_COUNTS_FROM_ZERO broke ABI and can't be used anymore. */
  46 #define PVCLOCK_COUNTS_FROM_ZERO (1 << 2)
  47 #endif /* __ASSEMBLY__ */
  48 #endif /* _ASM_X86_PVCLOCK_ABI_H */