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Diffstat (limited to 'include/asm-x86/pvclock-abi.h')
-rw-r--r-- | include/asm-x86/pvclock-abi.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/include/asm-x86/pvclock-abi.h b/include/asm-x86/pvclock-abi.h new file mode 100644 index 00000000000..6857f840b24 --- /dev/null +++ b/include/asm-x86/pvclock-abi.h | |||
@@ -0,0 +1,42 @@ | |||
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 | |||
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__ */ | ||
42 | #endif /* _ASM_X86_PVCLOCK_ABI_H_ */ | ||