1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Hypervisor Maintenance Interrupt (HMI) handling.
4 *
5 * Copyright 2015 IBM Corporation
6 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
7 */
8
9#undef DEBUG
10
11#include <linux/types.h>
12#include <linux/compiler.h>
13#include <asm/paca.h>
14#include <asm/hmi.h>
15#include <asm/processor.h>
16
17void wait_for_subcore_guest_exit(void)
18{
19	int i;
20
21	/*
22	 * NULL bitmap pointer indicates that KVM module hasn't
23	 * been loaded yet and hence no guests are running.
24	 * If no KVM is in use, no need to co-ordinate among threads
25	 * as all of them will always be in host and no one is going
26	 * to modify TB other than the opal hmi handler.
27	 * Hence, just return from here.
28	 */
29	if (!local_paca->sibling_subcore_state)
30		return;
31
32	for (i = 0; i < MAX_SUBCORE_PER_CORE; i++)
33		while (local_paca->sibling_subcore_state->in_guest[i])
34			cpu_relax();
35}
36
37void wait_for_tb_resync(void)
38{
39	if (!local_paca->sibling_subcore_state)
40		return;
41
42	while (test_bit(CORE_TB_RESYNC_REQ_BIT,
43				&local_paca->sibling_subcore_state->flags))
44		cpu_relax();
45}
46