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1965aae3 PA |
1 | #ifndef _ASM_X86_PVCLOCK_ABI_H |
2 | #define _ASM_X86_PVCLOCK_ABI_H | |
7af192c9 GH |
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 | ||
25 | struct 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 | ||
35 | struct pvclock_wall_clock { | |
36 | u32 version; | |
37 | u32 sec; | |
38 | u32 nsec; | |
39 | } __attribute__((__packed__)); | |
40 | ||
41 | #endif /* __ASSEMBLY__ */ | |
1965aae3 | 42 | #endif /* _ASM_X86_PVCLOCK_ABI_H */ |