cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
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sys_membarrier.c (1178B)

      1/*
      2 * Process-global memory barriers
      3 *
      4 * Copyright (c) 2018 Red Hat, Inc.
      5 *
      6 * Author: Paolo Bonzini <pbonzini@redhat.com>
      7 */
      8
      9#include "qemu/osdep.h"
     10#include "qemu/sys_membarrier.h"
     11#include "qemu/error-report.h"
     12
     13#ifdef CONFIG_LINUX
     14#include <linux/membarrier.h>
     15#include <sys/syscall.h>
     16
     17static int
     18membarrier(int cmd, int flags)
     19{
     20    return syscall(__NR_membarrier, cmd, flags);
     21}
     22#endif
     23
     24void smp_mb_global(void)
     25{
     26#if defined CONFIG_WIN32
     27    FlushProcessWriteBuffers();
     28#elif defined CONFIG_LINUX
     29    membarrier(MEMBARRIER_CMD_SHARED, 0);
     30#else
     31#error --enable-membarrier is not supported on this operating system.
     32#endif
     33}
     34
     35void smp_mb_global_init(void)
     36{
     37#ifdef CONFIG_LINUX
     38    int ret = membarrier(MEMBARRIER_CMD_QUERY, 0);
     39    if (ret < 0) {
     40        error_report("This QEMU binary requires the membarrier system call.");
     41        error_report("Please upgrade your system to a newer version of Linux");
     42        exit(1);
     43    }
     44    if (!(ret & MEMBARRIER_CMD_SHARED)) {
     45        error_report("This QEMU binary requires MEMBARRIER_CMD_SHARED support.");
     46        error_report("Please upgrade your system to a newer version of Linux");
     47        exit(1);
     48    }
     49#endif
     50}