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

filter-compress.c (5069B)

      1/*
      2 * Compress filter block driver
      3 *
      4 * Copyright (c) 2019 Virtuozzo International GmbH
      5 *
      6 * Author:
      7 *   Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
      8 *   (based on block/copy-on-read.c by Max Reitz)
      9 *
     10 * This program is free software; you can redistribute it and/or
     11 * modify it under the terms of the GNU General Public License as
     12 * published by the Free Software Foundation; either version 2 or
     13 * (at your option) any later version of the License.
     14 *
     15 * This program is distributed in the hope that it will be useful,
     16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
     17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     18 * GNU General Public License for more details.
     19 *
     20 * You should have received a copy of the GNU General Public License
     21 * along with this program; if not, see <http://www.gnu.org/licenses/>.
     22 */
     23
     24#include "qemu/osdep.h"
     25#include "block/block_int.h"
     26#include "qemu/module.h"
     27#include "qapi/error.h"
     28
     29
     30static int compress_open(BlockDriverState *bs, QDict *options, int flags,
     31                         Error **errp)
     32{
     33    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
     34                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
     35                               false, errp);
     36    if (!bs->file) {
     37        return -EINVAL;
     38    }
     39
     40    if (!bs->file->bs->drv || !block_driver_can_compress(bs->file->bs->drv)) {
     41        error_setg(errp,
     42                   "Compression is not supported for underlying format: %s",
     43                   bdrv_get_format_name(bs->file->bs) ?: "(no format)");
     44
     45        return -ENOTSUP;
     46    }
     47
     48    bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
     49        (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
     50
     51    bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
     52        ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
     53            bs->file->bs->supported_zero_flags);
     54
     55    return 0;
     56}
     57
     58
     59static int64_t compress_getlength(BlockDriverState *bs)
     60{
     61    return bdrv_getlength(bs->file->bs);
     62}
     63
     64
     65static int coroutine_fn compress_co_preadv_part(BlockDriverState *bs,
     66                                                int64_t offset, int64_t bytes,
     67                                                QEMUIOVector *qiov,
     68                                                size_t qiov_offset,
     69                                                BdrvRequestFlags flags)
     70{
     71    return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
     72                               flags);
     73}
     74
     75
     76static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs,
     77                                                 int64_t offset,
     78                                                 int64_t bytes,
     79                                                 QEMUIOVector *qiov,
     80                                                 size_t qiov_offset,
     81                                                 BdrvRequestFlags flags)
     82{
     83    return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,
     84                                flags | BDRV_REQ_WRITE_COMPRESSED);
     85}
     86
     87
     88static int coroutine_fn compress_co_pwrite_zeroes(BlockDriverState *bs,
     89                                                  int64_t offset, int64_t bytes,
     90                                                  BdrvRequestFlags flags)
     91{
     92    return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
     93}
     94
     95
     96static int coroutine_fn compress_co_pdiscard(BlockDriverState *bs,
     97                                             int64_t offset, int64_t bytes)
     98{
     99    return bdrv_co_pdiscard(bs->file, offset, bytes);
    100}
    101
    102
    103static void compress_refresh_limits(BlockDriverState *bs, Error **errp)
    104{
    105    BlockDriverInfo bdi;
    106    int ret;
    107
    108    if (!bs->file) {
    109        return;
    110    }
    111
    112    ret = bdrv_get_info(bs->file->bs, &bdi);
    113    if (ret < 0 || bdi.cluster_size == 0) {
    114        return;
    115    }
    116
    117    bs->bl.request_alignment = bdi.cluster_size;
    118}
    119
    120
    121static void compress_eject(BlockDriverState *bs, bool eject_flag)
    122{
    123    bdrv_eject(bs->file->bs, eject_flag);
    124}
    125
    126
    127static void compress_lock_medium(BlockDriverState *bs, bool locked)
    128{
    129    bdrv_lock_medium(bs->file->bs, locked);
    130}
    131
    132
    133static BlockDriver bdrv_compress = {
    134    .format_name                        = "compress",
    135
    136    .bdrv_open                          = compress_open,
    137    .bdrv_child_perm                    = bdrv_default_perms,
    138
    139    .bdrv_getlength                     = compress_getlength,
    140
    141    .bdrv_co_preadv_part                = compress_co_preadv_part,
    142    .bdrv_co_pwritev_part               = compress_co_pwritev_part,
    143    .bdrv_co_pwrite_zeroes              = compress_co_pwrite_zeroes,
    144    .bdrv_co_pdiscard                   = compress_co_pdiscard,
    145    .bdrv_refresh_limits                = compress_refresh_limits,
    146
    147    .bdrv_eject                         = compress_eject,
    148    .bdrv_lock_medium                   = compress_lock_medium,
    149
    150    .has_variable_length                = true,
    151    .is_filter                          = true,
    152};
    153
    154static void bdrv_compress_init(void)
    155{
    156    bdrv_register(&bdrv_compress);
    157}
    158
    159block_init(bdrv_compress_init);