Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 527 insertions, 0 deletions

diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
new file mode 100644
index 000000000..1914baf45
--- /dev/null
+++ b/block/qcow2-threads.c
@@ -0,0 +1,527 @@
+/*
+ * Threaded data processing for Qcow2: compression, encryption
+ *
+ * Copyright (c) 2004-2006 Fabrice Bellard
+ * Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+
+#define ZLIB_CONST
+#include <zlib.h>
+
+#ifdef CONFIG_ZSTD
+#include <zstd.h>
+#include <zstd_errors.h>
+#endif
+
+#include "qcow2.h"
+#include "block/thread-pool.h"
+#include "crypto.h"
+
+static int coroutine_fn
+qcow2_co_process(BlockDriverState *bs, ThreadPoolFunc *func, void *arg)
+{
+    int ret;
+    BDRVQcow2State *s = bs->opaque;
+    ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
+
+    qemu_co_mutex_lock(&s->lock);
+    while (s->nb_threads >= QCOW2_MAX_THREADS) {
+        qemu_co_queue_wait(&s->thread_task_queue, &s->lock);
+    }
+    s->nb_threads++;
+    qemu_co_mutex_unlock(&s->lock);
+
+    ret = thread_pool_submit_co(pool, func, arg);
+
+    qemu_co_mutex_lock(&s->lock);
+    s->nb_threads--;
+    qemu_co_queue_next(&s->thread_task_queue);
+    qemu_co_mutex_unlock(&s->lock);
+
+    return ret;
+}
+
+
+/*
+ * Compression
+ */
+
+typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size,
+                                     const void *src, size_t src_size);
+typedef struct Qcow2CompressData {
+    void *dest;
+    size_t dest_size;
+    const void *src;
+    size_t src_size;
+    ssize_t ret;
+
+    Qcow2CompressFunc func;
+} Qcow2CompressData;
+
+/*
+ * qcow2_zlib_compress()
+ *
+ * Compress @src_size bytes of data using zlib compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: compressed size on success
+ *          -ENOMEM destination buffer is not enough to store compressed data
+ *          -EIO    on any other error
+ */
+static ssize_t qcow2_zlib_compress(void *dest, size_t dest_size,
+                                   const void *src, size_t src_size)
+{
+    ssize_t ret;
+    z_stream strm;
+
+    /* best compression, small window, no zlib header */
+    memset(&strm, 0, sizeof(strm));
+    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+                       -12, 9, Z_DEFAULT_STRATEGY);
+    if (ret != Z_OK) {
+        return -EIO;
+    }
+
+    /*
+     * strm.next_in is not const in old zlib versions, such as those used on
+     * OpenBSD/NetBSD, so cast the const away
+     */
+    strm.avail_in = src_size;
+    strm.next_in = (void *) src;
+    strm.avail_out = dest_size;
+    strm.next_out = dest;
+
+    ret = deflate(&strm, Z_FINISH);
+    if (ret == Z_STREAM_END) {
+        ret = dest_size - strm.avail_out;
+    } else {
+        ret = (ret == Z_OK ? -ENOMEM : -EIO);
+    }
+
+    deflateEnd(&strm);
+
+    return ret;
+}
+
+/*
+ * qcow2_zlib_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using zlib compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ *          -EIO on fail
+ */
+static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
+                                     const void *src, size_t src_size)
+{
+    int ret;
+    z_stream strm;
+
+    memset(&strm, 0, sizeof(strm));
+    strm.avail_in = src_size;
+    strm.next_in = (void *) src;
+    strm.avail_out = dest_size;
+    strm.next_out = dest;
+
+    ret = inflateInit2(&strm, -12);
+    if (ret != Z_OK) {
+        return -EIO;
+    }
+
+    ret = inflate(&strm, Z_FINISH);
+    if ((ret == Z_STREAM_END || ret == Z_BUF_ERROR) && strm.avail_out == 0) {
+        /*
+         * We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
+         * @src buffer may be processed partly (because in qcow2 we know size of
+         * compressed data with precision of one sector)
+         */
+        ret = 0;
+    } else {
+        ret = -EIO;
+    }
+
+    inflateEnd(&strm);
+
+    return ret;
+}
+
+#ifdef CONFIG_ZSTD
+
+/*
+ * qcow2_zstd_compress()
+ *
+ * Compress @src_size bytes of data using zstd compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: compressed size on success
+ *          -ENOMEM destination buffer is not enough to store compressed data
+ *          -EIO    on any other error
+ */
+static ssize_t qcow2_zstd_compress(void *dest, size_t dest_size,
+                                   const void *src, size_t src_size)
+{
+    ssize_t ret;
+    size_t zstd_ret;
+    ZSTD_outBuffer output = {
+        .dst = dest,
+        .size = dest_size,
+        .pos = 0
+    };
+    ZSTD_inBuffer input = {
+        .src = src,
+        .size = src_size,
+        .pos = 0
+    };
+    ZSTD_CCtx *cctx = ZSTD_createCCtx();
+
+    if (!cctx) {
+        return -EIO;
+    }
+    /*
+     * Use the zstd streamed interface for symmetry with decompression,
+     * where streaming is essential since we don't record the exact
+     * compressed size.
+     *
+     * ZSTD_compressStream2() tries to compress everything it could
+     * with a single call. Although, ZSTD docs says that:
+     * "You must continue calling ZSTD_compressStream2() with ZSTD_e_end
+     * until it returns 0, at which point you are free to start a new frame",
+     * in out tests we saw the only case when it returned with >0 -
+     * when the output buffer was too small. In that case,
+     * ZSTD_compressStream2() expects a bigger buffer on the next call.
+     * We can't provide a bigger buffer because we are limited with dest_size
+     * which we pass to the ZSTD_compressStream2() at once.
+     * So, we don't need any loops and just abort the compression when we
+     * don't get 0 result on the first call.
+     */
+    zstd_ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
+
+    if (zstd_ret) {
+        if (zstd_ret > output.size - output.pos) {
+            ret = -ENOMEM;
+        } else {
+            ret = -EIO;
+        }
+        goto out;
+    }
+
+    /* make sure that zstd didn't overflow the dest buffer */
+    assert(output.pos <= dest_size);
+    ret = output.pos;
+out:
+    ZSTD_freeCCtx(cctx);
+    return ret;
+}
+
+/*
+ * qcow2_zstd_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using zstd compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ *          -EIO on any error
+ */
+static ssize_t qcow2_zstd_decompress(void *dest, size_t dest_size,
+                                     const void *src, size_t src_size)
+{
+    size_t zstd_ret = 0;
+    ssize_t ret = 0;
+    ZSTD_outBuffer output = {
+        .dst = dest,
+        .size = dest_size,
+        .pos = 0
+    };
+    ZSTD_inBuffer input = {
+        .src = src,
+        .size = src_size,
+        .pos = 0
+    };
+    ZSTD_DCtx *dctx = ZSTD_createDCtx();
+
+    if (!dctx) {
+        return -EIO;
+    }
+
+    /*
+     * The compressed stream from the input buffer may consist of more
+     * than one zstd frame. So we iterate until we get a fully
+     * uncompressed cluster.
+     * From zstd docs related to ZSTD_decompressStream:
+     * "return : 0 when a frame is completely decoded and fully flushed"
+     * We suppose that this means: each time ZSTD_decompressStream reads
+     * only ONE full frame and returns 0 if and only if that frame
+     * is completely decoded and flushed. Only after returning 0,
+     * ZSTD_decompressStream reads another ONE full frame.
+     */
+    while (output.pos < output.size) {
+        size_t last_in_pos = input.pos;
+        size_t last_out_pos = output.pos;
+        zstd_ret = ZSTD_decompressStream(dctx, &output, &input);
+
+        if (ZSTD_isError(zstd_ret)) {
+            ret = -EIO;
+            break;
+        }
+
+        /*
+         * The ZSTD manual is vague about what to do if it reads
+         * the buffer partially, and we don't want to get stuck
+         * in an infinite loop where ZSTD_decompressStream
+         * returns > 0 waiting for another input chunk. So, we add
+         * a check which ensures that the loop makes some progress
+         * on each step.
+         */
+        if (last_in_pos >= input.pos &&
+            last_out_pos >= output.pos) {
+            ret = -EIO;
+            break;
+        }
+    }
+    /*
+     * Make sure that we have the frame fully flushed here
+     * if not, we somehow managed to get uncompressed cluster
+     * greater then the cluster size, possibly because of its
+     * damage.
+     */
+    if (zstd_ret > 0) {
+        ret = -EIO;
+    }
+
+    ZSTD_freeDCtx(dctx);
+    assert(ret == 0 || ret == -EIO);
+    return ret;
+}
+#endif
+
+static int qcow2_compress_pool_func(void *opaque)
+{
+    Qcow2CompressData *data = opaque;
+
+    data->ret = data->func(data->dest, data->dest_size,
+                           data->src, data->src_size);
+
+    return 0;
+}
+
+static ssize_t coroutine_fn
+qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
+                     const void *src, size_t src_size, Qcow2CompressFunc func)
+{
+    Qcow2CompressData arg = {
+        .dest = dest,
+        .dest_size = dest_size,
+        .src = src,
+        .src_size = src_size,
+        .func = func,
+    };
+
+    qcow2_co_process(bs, qcow2_compress_pool_func, &arg);
+
+    return arg.ret;
+}
+
+/*
+ * qcow2_co_compress()
+ *
+ * Compress @src_size bytes of data using the compression
+ * method defined by the image compression type
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: compressed size on success
+ *          a negative error code on failure
+ */
+ssize_t coroutine_fn
+qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
+                  const void *src, size_t src_size)
+{
+    BDRVQcow2State *s = bs->opaque;
+    Qcow2CompressFunc fn;
+
+    switch (s->compression_type) {
+    case QCOW2_COMPRESSION_TYPE_ZLIB:
+        fn = qcow2_zlib_compress;
+        break;
+
+#ifdef CONFIG_ZSTD
+    case QCOW2_COMPRESSION_TYPE_ZSTD:
+        fn = qcow2_zstd_compress;
+        break;
+#endif
+    default:
+        abort();
+    }
+
+    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
+}
+
+/*
+ * qcow2_co_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using the compression method defined by the image
+ * compression type
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ *          a negative error code on failure
+ */
+ssize_t coroutine_fn
+qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
+                    const void *src, size_t src_size)
+{
+    BDRVQcow2State *s = bs->opaque;
+    Qcow2CompressFunc fn;
+
+    switch (s->compression_type) {
+    case QCOW2_COMPRESSION_TYPE_ZLIB:
+        fn = qcow2_zlib_decompress;
+        break;
+
+#ifdef CONFIG_ZSTD
+    case QCOW2_COMPRESSION_TYPE_ZSTD:
+        fn = qcow2_zstd_decompress;
+        break;
+#endif
+    default:
+        abort();
+    }
+
+    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
+}
+
+
+/*
+ * Cryptography
+ */
+
+/*
+ * Qcow2EncDecFunc: common prototype of qcrypto_block_encrypt() and
+ * qcrypto_block_decrypt() functions.
+ */
+typedef int (*Qcow2EncDecFunc)(QCryptoBlock *block, uint64_t offset,
+                               uint8_t *buf, size_t len, Error **errp);
+
+typedef struct Qcow2EncDecData {
+    QCryptoBlock *block;
+    uint64_t offset;
+    uint8_t *buf;
+    size_t len;
+
+    Qcow2EncDecFunc func;
+} Qcow2EncDecData;
+
+static int qcow2_encdec_pool_func(void *opaque)
+{
+    Qcow2EncDecData *data = opaque;
+
+    return data->func(data->block, data->offset, data->buf, data->len, NULL);
+}
+
+static int coroutine_fn
+qcow2_co_encdec(BlockDriverState *bs, uint64_t host_offset,
+                uint64_t guest_offset, void *buf, size_t len,
+                Qcow2EncDecFunc func)
+{
+    BDRVQcow2State *s = bs->opaque;
+    Qcow2EncDecData arg = {
+        .block = s->crypto,
+        .offset = s->crypt_physical_offset ? host_offset : guest_offset,
+        .buf = buf,
+        .len = len,
+        .func = func,
+    };
+    uint64_t sector_size;
+
+    assert(s->crypto);
+
+    sector_size = qcrypto_block_get_sector_size(s->crypto);
+    assert(QEMU_IS_ALIGNED(guest_offset, sector_size));
+    assert(QEMU_IS_ALIGNED(host_offset, sector_size));
+    assert(QEMU_IS_ALIGNED(len, sector_size));
+
+    return len == 0 ? 0 : qcow2_co_process(bs, qcow2_encdec_pool_func, &arg);
+}
+
+/*
+ * qcow2_co_encrypt()
+ *
+ * Encrypts one or more contiguous aligned sectors
+ *
+ * @host_offset - underlying storage offset of the first sector of the
+ * data to be encrypted
+ *
+ * @guest_offset - guest (virtual) offset of the first sector of the
+ * data to be encrypted
+ *
+ * @buf - buffer with the data to encrypt, that after encryption
+ *        will be written to the underlying storage device at
+ *        @host_offset
+ *
+ * @len - length of the buffer (must be a multiple of the encryption
+ *        sector size)
+ *
+ * Depending on the encryption method, @host_offset and/or @guest_offset
+ * may be used for generating the initialization vector for
+ * encryption.
+ *
+ * Note that while the whole range must be aligned on sectors, it
+ * does not have to be aligned on clusters and can also cross cluster
+ * boundaries
+ */
+int coroutine_fn
+qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,
+                 uint64_t guest_offset, void *buf, size_t len)
+{
+    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
+                           qcrypto_block_encrypt);
+}
+
+/*
+ * qcow2_co_decrypt()
+ *
+ * Decrypts one or more contiguous aligned sectors
+ * Similar to qcow2_co_encrypt
+ */
+int coroutine_fn
+qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,
+                 uint64_t guest_offset, void *buf, size_t len)
+{
+    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,
+                           qcrypto_block_decrypt);
+}