KVM: x86: zero kvmclock_offset when vcpu0 initializes kvmclock system MSR
Initialize kvmclock base, on kvmclock system MSR write time,
so that the guest sees kvmclock counting from zero.
This matches baremetal behaviour when kvmclock in guest
sets sched clock stable.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
[Remove unnecessary comment. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2211213..79dde16 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1700,6 +1700,8 @@
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;
@@ -2282,6 +2284,8 @@
&vcpu->requests);
ka->boot_vcpu_runs_old_kvmclock = tmp;
+
+ ka->kvmclock_offset = -get_kernel_ns();
}
vcpu->arch.time = data;