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