static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
	int version;
	int r;
	struct pvclock_wall_clock wc;
	struct timespec boot;

	if (!wall_clock)
		return;

	r = kvm_read_guest(kvm, wall_clock, &version, sizeof(version));
	if (r)
		return;

	if (version & 1)
		++version;  /* first time write, random junk */

	++version;

	kvm_write_guest(kvm, wall_clock, &version, sizeof(version));

	/*
	 * The guest calculates current wall clock time by adding
	 * system time (updated by kvm_guest_time_update below) to the
	 * wall clock specified here.  guest system time equals host
	 * system time for us, thus we must fill in host boot time here.
	 */
	getboottime(&boot);

	if (kvm->arch.kvmclock_offset) {
		struct timespec ts = ns_to_timespec(kvm->arch.kvmclock_offset);
		boot = timespec_sub(boot, ts);
	}
	wc.sec = boot.tv_sec;
	wc.nsec = boot.tv_nsec;
	wc.version = version;

	kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc));

	version++;
	kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
}
Unknown