1*50006539SOliver Upton /* SPDX-License-Identifier: GPL-2.0 */ 2*50006539SOliver Upton #ifndef _ASM_X86_PVCLOCK_ABI_H 3*50006539SOliver Upton #define _ASM_X86_PVCLOCK_ABI_H 4*50006539SOliver Upton #ifndef __ASSEMBLY__ 5*50006539SOliver Upton 6*50006539SOliver Upton /* 7*50006539SOliver Upton * These structs MUST NOT be changed. 8*50006539SOliver Upton * They are the ABI between hypervisor and guest OS. 9*50006539SOliver Upton * Both Xen and KVM are using this. 10*50006539SOliver Upton * 11*50006539SOliver Upton * pvclock_vcpu_time_info holds the system time and the tsc timestamp 12*50006539SOliver Upton * of the last update. So the guest can use the tsc delta to get a 13*50006539SOliver Upton * more precise system time. There is one per virtual cpu. 14*50006539SOliver Upton * 15*50006539SOliver Upton * pvclock_wall_clock references the point in time when the system 16*50006539SOliver Upton * time was zero (usually boot time), thus the guest calculates the 17*50006539SOliver Upton * current wall clock by adding the system time. 18*50006539SOliver Upton * 19*50006539SOliver Upton * Protocol for the "version" fields is: hypervisor raises it (making 20*50006539SOliver Upton * it uneven) before it starts updating the fields and raises it again 21*50006539SOliver Upton * (making it even) when it is done. Thus the guest can make sure the 22*50006539SOliver Upton * time values it got are consistent by checking the version before 23*50006539SOliver Upton * and after reading them. 24*50006539SOliver Upton */ 25*50006539SOliver Upton 26*50006539SOliver Upton struct pvclock_vcpu_time_info { 27*50006539SOliver Upton u32 version; 28*50006539SOliver Upton u32 pad0; 29*50006539SOliver Upton u64 tsc_timestamp; 30*50006539SOliver Upton u64 system_time; 31*50006539SOliver Upton u32 tsc_to_system_mul; 32*50006539SOliver Upton s8 tsc_shift; 33*50006539SOliver Upton u8 flags; 34*50006539SOliver Upton u8 pad[2]; 35*50006539SOliver Upton } __attribute__((__packed__)); /* 32 bytes */ 36*50006539SOliver Upton 37*50006539SOliver Upton struct pvclock_wall_clock { 38*50006539SOliver Upton u32 version; 39*50006539SOliver Upton u32 sec; 40*50006539SOliver Upton u32 nsec; 41*50006539SOliver Upton } __attribute__((__packed__)); 42*50006539SOliver Upton 43*50006539SOliver Upton #define PVCLOCK_TSC_STABLE_BIT (1 << 0) 44*50006539SOliver Upton #define PVCLOCK_GUEST_STOPPED (1 << 1) 45*50006539SOliver Upton /* PVCLOCK_COUNTS_FROM_ZERO broke ABI and can't be used anymore. */ 46*50006539SOliver Upton #define PVCLOCK_COUNTS_FROM_ZERO (1 << 2) 47*50006539SOliver Upton #endif /* __ASSEMBLY__ */ 48*50006539SOliver Upton #endif /* _ASM_X86_PVCLOCK_ABI_H */ 49