[42/93] kvmclock: count total_sleep_time when updating guest clock

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Jason Wang <jasowang@xxxxxxxxxx>

commit 923de3cf5bf12049628019010e36623fca5ef6d1 upstream.

Current kvm wallclock does not consider the total_sleep_time which could cause
wrong wallclock in guest after host suspend/resume. This patch solve
this issue by counting total_sleep_time to get the correct host boot time.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Glauber Costa <glommer@xxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 arch/x86/kvm/x86.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -583,7 +583,7 @@ static void kvm_write_wall_clock(struct
 {
 	static int version;
 	struct pvclock_wall_clock wc;
-	struct timespec now, sys, boot;
+	struct timespec boot;
 
 	if (!wall_clock)
 		return;
@@ -598,9 +598,7 @@ static void kvm_write_wall_clock(struct
 	 * wall clock specified here.  guest system time equals host
 	 * system time for us, thus we must fill in host boot time here.
 	 */
-	now = current_kernel_time();
-	ktime_get_ts(&sys);
-	boot = ns_to_timespec(timespec_to_ns(&now) - timespec_to_ns(&sys));
+	getboottime(&boot);
 
 	wc.sec = boot.tv_sec;
 	wc.nsec = boot.tv_nsec;
@@ -675,6 +673,7 @@ static void kvm_write_guest_time(struct
 	local_irq_save(flags);
 	kvm_get_msr(v, MSR_IA32_TSC, &vcpu->hv_clock.tsc_timestamp);
 	ktime_get_ts(&ts);
+	monotonic_to_bootbased(&ts);
 	local_irq_restore(flags);
 
 	/* With all the info we got, fill in the values */


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