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 */
49