cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

aio-wait.c (2178B)

      1/*
      2 * AioContext wait support
      3 *
      4 * Copyright (C) 2018 Red Hat, Inc.
      5 *
      6 * Permission is hereby granted, free of charge, to any person obtaining a copy
      7 * of this software and associated documentation files (the "Software"), to deal
      8 * in the Software without restriction, including without limitation the rights
      9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     10 * copies of the Software, and to permit persons to whom the Software is
     11 * furnished to do so, subject to the following conditions:
     12 *
     13 * The above copyright notice and this permission notice shall be included in
     14 * all copies or substantial portions of the Software.
     15 *
     16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     22 * THE SOFTWARE.
     23 */
     24
     25#include "qemu/osdep.h"
     26#include "qemu/main-loop.h"
     27#include "block/aio-wait.h"
     28
     29AioWait global_aio_wait;
     30
     31static void dummy_bh_cb(void *opaque)
     32{
     33    /* The point is to make AIO_WAIT_WHILE()'s aio_poll() return */
     34}
     35
     36void aio_wait_kick(void)
     37{
     38    /* The barrier (or an atomic op) is in the caller.  */
     39    if (qatomic_read(&global_aio_wait.num_waiters)) {
     40        aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL);
     41    }
     42}
     43
     44typedef struct {
     45    bool done;
     46    QEMUBHFunc *cb;
     47    void *opaque;
     48} AioWaitBHData;
     49
     50/* Context: BH in IOThread */
     51static void aio_wait_bh(void *opaque)
     52{
     53    AioWaitBHData *data = opaque;
     54
     55    data->cb(data->opaque);
     56
     57    data->done = true;
     58    aio_wait_kick();
     59}
     60
     61void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
     62{
     63    AioWaitBHData data = {
     64        .cb = cb,
     65        .opaque = opaque,
     66    };
     67
     68    assert(qemu_get_current_aio_context() == qemu_get_aio_context());
     69
     70    aio_bh_schedule_oneshot(ctx, aio_wait_bh, &data);
     71    AIO_WAIT_WHILE(ctx, !data.done);
     72}