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
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
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 }