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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write-threshold.c (1699B)

      1/*
      2 * QEMU System Emulator block write threshold notification
      3 *
      4 * Copyright Red Hat, Inc. 2014
      5 *
      6 * Authors:
      7 *  Francesco Romani <fromani@redhat.com>
      8 *
      9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
     10 * See the COPYING.LIB file in the top-level directory.
     11 */
     12
     13#include "qemu/osdep.h"
     14#include "block/block_int.h"
     15#include "block/write-threshold.h"
     16#include "qapi/error.h"
     17#include "qapi/qapi-commands-block-core.h"
     18#include "qapi/qapi-events-block-core.h"
     19
     20uint64_t bdrv_write_threshold_get(const BlockDriverState *bs)
     21{
     22    return bs->write_threshold_offset;
     23}
     24
     25void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes)
     26{
     27    bs->write_threshold_offset = threshold_bytes;
     28}
     29
     30void qmp_block_set_write_threshold(const char *node_name,
     31                                   uint64_t threshold_bytes,
     32                                   Error **errp)
     33{
     34    BlockDriverState *bs;
     35    AioContext *aio_context;
     36
     37    bs = bdrv_find_node(node_name);
     38    if (!bs) {
     39        error_setg(errp, "Device '%s' not found", node_name);
     40        return;
     41    }
     42
     43    aio_context = bdrv_get_aio_context(bs);
     44    aio_context_acquire(aio_context);
     45
     46    bdrv_write_threshold_set(bs, threshold_bytes);
     47
     48    aio_context_release(aio_context);
     49}
     50
     51void bdrv_write_threshold_check_write(BlockDriverState *bs, int64_t offset,
     52                                      int64_t bytes)
     53{
     54    int64_t end = offset + bytes;
     55    uint64_t wtr = bs->write_threshold_offset;
     56
     57    if (wtr > 0 && end > wtr) {
     58        qapi_event_send_block_write_threshold(bs->node_name, end - wtr, wtr);
     59
     60        /* autodisable to avoid flooding the monitor */
     61        bdrv_write_threshold_set(bs, 0);
     62    }
     63}