mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 05:16:53 +07:00
7af192c954
This patch adds structs for the paravirt clocksource ABI used by both xen and kvm (pvclock-abi.h). It also adds some helper functions to read system time and wall clock time from a paravirtual clocksource (pvclock.[ch]). They are based on the xen code. They are enabled using CONFIG_PARAVIRT_CLOCK. Subsequent patches of this series will put the code in use. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
43 lines
1.3 KiB
C
43 lines
1.3 KiB
C
#ifndef _ASM_X86_PVCLOCK_ABI_H_
|
|
#define _ASM_X86_PVCLOCK_ABI_H_
|
|
#ifndef __ASSEMBLY__
|
|
|
|
/*
|
|
* These structs MUST NOT be changed.
|
|
* They are the ABI between hypervisor and guest OS.
|
|
* Both Xen and KVM are using this.
|
|
*
|
|
* pvclock_vcpu_time_info holds the system time and the tsc timestamp
|
|
* of the last update. So the guest can use the tsc delta to get a
|
|
* more precise system time. There is one per virtual cpu.
|
|
*
|
|
* pvclock_wall_clock references the point in time when the system
|
|
* time was zero (usually boot time), thus the guest calculates the
|
|
* current wall clock by adding the system time.
|
|
*
|
|
* Protocol for the "version" fields is: hypervisor raises it (making
|
|
* it uneven) before it starts updating the fields and raises it again
|
|
* (making it even) when it is done. Thus the guest can make sure the
|
|
* time values it got are consistent by checking the version before
|
|
* and after reading them.
|
|
*/
|
|
|
|
struct pvclock_vcpu_time_info {
|
|
u32 version;
|
|
u32 pad0;
|
|
u64 tsc_timestamp;
|
|
u64 system_time;
|
|
u32 tsc_to_system_mul;
|
|
s8 tsc_shift;
|
|
u8 pad[3];
|
|
} __attribute__((__packed__)); /* 32 bytes */
|
|
|
|
struct pvclock_wall_clock {
|
|
u32 version;
|
|
u32 sec;
|
|
u32 nsec;
|
|
} __attribute__((__packed__));
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
#endif /* _ASM_X86_PVCLOCK_ABI_H_ */
|