cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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book3s_hv_hmi.c (1181B)

      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, 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
     42void 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}