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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 
wait_for_subcore_guest_exit(void)17 void 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 
wait_for_tb_resync(void)37 void 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