Merge tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv fix from Wei Liu:
 "One patch from Vitaly to fix reenlightenment notifications"

* tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Properly suspend/resume reenlightenment notifications

arch/x86/hyperv/hv_init.c

@@ -226,10 +226,18 @@ static int hv_cpu_die(unsigned int cpu)
 
 	rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 	if (re_ctrl.target_vp == hv_vp_index[cpu]) {
-		/* Reassign to some other online CPU */
+		/*
+		 * Reassign reenlightenment notifications to some other online
+		 * CPU or just disable the feature if there are no online CPUs
+		 * left (happens on hibernation).
+		 */
 		new_cpu = cpumask_any_but(cpu_online_mask, cpu);
 
+		if (new_cpu < nr_cpu_ids)
 			re_ctrl.target_vp = hv_vp_index[new_cpu];
+		else
+			re_ctrl.enabled = 0;
+
 		wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 	}
 
@@ -293,6 +301,13 @@ static void hv_resume(void)
 
 	hv_hypercall_pg = hv_hypercall_pg_saved;
 	hv_hypercall_pg_saved = NULL;
+
+	/*
+	 * Reenlightenment notifications are disabled by hv_cpu_die(0),
+	 * reenable them here if hv_reenlightenment_cb was previously set.
+	 */
+	if (hv_reenlightenment_cb)
+		set_hv_tscchange_cb(hv_reenlightenment_cb);
 }
 
 /* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */