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 b7e60c5aedd2b63f16ef06fde4f81ca032211bc5.
And adds a note to the definition of PVCLOCK_COUNTS_FROM_ZERO.
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
arch/x86/include/asm/pvclock-abi.h | 1 +
arch/x86/kvm/x86.c | 4 ----
2 files changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/pvclock-abi.h b/arch/x86/include/asm/pvclock-abi.h
index 655e07a48f6c..67f08230103a 100644
--- a/arch/x86/include/asm/pvclock-abi.h
+++ b/arch/x86/include/asm/pvclock-abi.h
@@ -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 */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 18d59b584dee..34d33f4757d2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1707,8 +1707,6 @@ 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;
@@ -2006,8 +2004,6 @@ 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;
--
2.5.2
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