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Commit 9bac175d authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
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Revert "KVM: x86: zero kvmclock_offset when vcpu0 initializes kvmclock system MSR" 



Shifting pvclock_vcpu_time_info.system_time on write to KVM system time
MSR is a change of ABI.  Probably only 2.6.16 based SLES 10 breaks due
to its custom enhancements to kvmclock, but KVM never declared the MSR
only for one-shot initialization.  (Doc says that only one write is
needed.)

This reverts commit b7e60c5a.
And adds a note to the definition of PVCLOCK_COUNTS_FROM_ZERO.

Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Acked-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9ffecb10

arch/x86/include/asm/pvclock-abi.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ struct pvclock_wall_clock { 


#define PVCLOCK_TSC_STABLE_BIT	(1 << 0)

#define PVCLOCK_GUEST_STOPPED	(1 << 1)

/* PVCLOCK_COUNTS_FROM_ZERO broke ABI and can't be used anymore. */

#define PVCLOCK_COUNTS_FROM_ZERO (1 << 2)

#endif /* __ASSEMBLY__ */

#endif /* _ASM_X86_PVCLOCK_ABI_H */

arch/x86/kvm/x86.c

+0 −4
Original line number Diff line number Diff line
@@ -1708,8 +1708,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) 
		vcpu->pvclock_set_guest_stopped_request = false;

	}



	pvclock_flags |= PVCLOCK_COUNTS_FROM_ZERO;



	/* If the host uses TSC clocksource, then it is stable */

	if (use_master_clock)

		pvclock_flags |= PVCLOCK_TSC_STABLE_BIT;
@@ -2007,8 +2005,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
					&vcpu->requests);



			ka->boot_vcpu_runs_old_kvmclock = tmp;



			ka->kvmclock_offset = -get_kernel_ns();

		}



		vcpu->arch.time = data;