kvmclock: count total_sleep_time when updating guest clock

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.

Cc: stable@kernel.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/x86.c

@@ -670,7 +670,7 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
 {
 	static int version;
 	struct pvclock_wall_clock wc;
-	struct timespec now, sys, boot;
+	struct timespec boot;
 
 	if (!wall_clock)
 		return;
@@ -685,9 +685,7 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
 	 * 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;
@@ -762,6 +760,7 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
 	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 */