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, or running |
24 | * on POWER9 or newer CPU. |
25 | * |
26 | * If no KVM is in use, no need to co-ordinate among threads |
27 | * as all of them will always be in host and no one is going |
28 | * to modify TB other than the opal hmi handler. |
29 | * |
30 | * POWER9 and newer don't need this synchronisation. |
31 | * |
32 | * Hence, just return from here. |
33 | */ |
34 | if (!local_paca->sibling_subcore_state) |
35 | return; |
36 | |
37 | for (i = 0; i < MAX_SUBCORE_PER_CORE; i++) |
38 | while (local_paca->sibling_subcore_state->in_guest[i]) |
39 | cpu_relax(); |
40 | } |
41 | |
42 | void wait_for_tb_resync(void) |
43 | { |
44 | if (!local_paca->sibling_subcore_state) |
45 | return; |
46 | |
47 | while (test_bit(CORE_TB_RESYNC_REQ_BIT, |
48 | &local_paca->sibling_subcore_state->flags)) |
49 | cpu_relax(); |
50 | } |
51 | |