crypto: support multiple threads accessing one QCryptoBlock

The two thing that should be handled are cipher and ivgen. For ivgen
the solution is just mutex, as iv calculations should not be long in
comparison with encryption/decryption. And for cipher let's just keep
per-thread ciphers.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

9 files changed, 172 insertions, 44 deletions

diff --git a/block/crypto.c b/block/crypto.c
index 33ee01bebd..f0a5f6b987 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -229,6 +229,7 @@ static int block_crypto_open_generic(QCryptoBlockFormat format,
                                        block_crypto_read_func,
                                        bs,
                                        cflags,
+                                       1,
                                        errp);
 
     if (!crypto->block) {
diff --git a/block/qcow.c b/block/qcow.c
index 4518cb4c35..0a235bf393 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -213,7 +213,7 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
                 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
             }
             s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
-                                           NULL, NULL, cflags, errp);
+                                           NULL, NULL, cflags, 1, errp);
             if (!s->crypto) {
                 ret = -EINVAL;
                 goto fail;
diff --git a/block/qcow2.c b/block/qcow2.c
index 991d6ac91b..bc8868c36a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -294,7 +294,7 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
             }
             s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.",
                                            qcow2_crypto_hdr_read_func,
-                                           bs, cflags, errp);
+                                           bs, cflags, 1, errp);
             if (!s->crypto) {
                 return -EINVAL;
             }
@@ -1445,7 +1445,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
                 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
             }
             s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.",
-                                           NULL, NULL, cflags, errp);
+                                           NULL, NULL, cflags, 1, errp);
             if (!s->crypto) {
                 ret = -EINVAL;
                 goto fail;
diff --git a/crypto/block-luks.c b/crypto/block-luks.c
index e486e7ee94..6bac79c3ab 100644
--- a/crypto/block-luks.c
+++ b/crypto/block-luks.c
@@ -636,6 +636,7 @@ qcrypto_block_luks_open(QCryptoBlock *block,
                         QCryptoBlockReadFunc readfunc,
                         void *opaque,
                         unsigned int flags,
+                        size_t n_threads,
                         Error **errp)
 {
     QCryptoBlockLUKS *luks;
@@ -836,11 +837,10 @@ qcrypto_block_luks_open(QCryptoBlock *block,
             goto fail;
         }
 
-        block->cipher = qcrypto_cipher_new(cipheralg,
-                                           ciphermode,
-                                           masterkey, masterkeylen,
-                                           errp);
-        if (!block->cipher) {
+        ret = qcrypto_block_init_cipher(block, cipheralg, ciphermode,
+                                        masterkey, masterkeylen, n_threads,
+                                        errp);
+        if (ret < 0) {
             ret = -ENOTSUP;
             goto fail;
         }
@@ -863,7 +863,7 @@ qcrypto_block_luks_open(QCryptoBlock *block,
 
  fail:
     g_free(masterkey);
-    qcrypto_cipher_free(block->cipher);
+    qcrypto_block_free_cipher(block);
     qcrypto_ivgen_free(block->ivgen);
     g_free(luks);
     g_free(password);
@@ -1030,11 +1030,9 @@ qcrypto_block_luks_create(QCryptoBlock *block,
 
 
     /* Setup the block device payload encryption objects */
-    block->cipher = qcrypto_cipher_new(luks_opts.cipher_alg,
-                                       luks_opts.cipher_mode,
-                                       masterkey, luks->header.key_bytes,
-                                       errp);
-    if (!block->cipher) {
+    if (qcrypto_block_init_cipher(block, luks_opts.cipher_alg,
+                                  luks_opts.cipher_mode, masterkey,
+                                  luks->header.key_bytes, 1, errp) < 0) {
         goto error;
     }
 
@@ -1341,7 +1339,7 @@ qcrypto_block_luks_create(QCryptoBlock *block,
     qcrypto_ivgen_free(ivgen);
     qcrypto_cipher_free(cipher);
 
-    qcrypto_cipher_free(block->cipher);
+    qcrypto_block_free_cipher(block);
     qcrypto_ivgen_free(block->ivgen);
 
     g_free(luks);
diff --git a/crypto/block-qcow.c b/crypto/block-qcow.c
index 36bf5f09b7..cefb3b2a7b 100644
--- a/crypto/block-qcow.c
+++ b/crypto/block-qcow.c
@@ -44,6 +44,7 @@ qcrypto_block_qcow_has_format(const uint8_t *buf G_GNUC_UNUSED,
 static int
 qcrypto_block_qcow_init(QCryptoBlock *block,
                         const char *keysecret,
+                        size_t n_threads,
                         Error **errp)
 {
     char *password;
@@ -71,11 +72,11 @@ qcrypto_block_qcow_init(QCryptoBlock *block,
         goto fail;
     }
 
-    block->cipher = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_128,
-                                       QCRYPTO_CIPHER_MODE_CBC,
-                                       keybuf, G_N_ELEMENTS(keybuf),
-                                       errp);
-    if (!block->cipher) {
+    ret = qcrypto_block_init_cipher(block, QCRYPTO_CIPHER_ALG_AES_128,
+                                    QCRYPTO_CIPHER_MODE_CBC,
+                                    keybuf, G_N_ELEMENTS(keybuf),
+                                    n_threads, errp);
+    if (ret < 0) {
         ret = -ENOTSUP;
         goto fail;
     }
@@ -86,7 +87,7 @@ qcrypto_block_qcow_init(QCryptoBlock *block,
     return 0;
 
  fail:
-    qcrypto_cipher_free(block->cipher);
+    qcrypto_block_free_cipher(block);
     qcrypto_ivgen_free(block->ivgen);
     return ret;
 }
@@ -99,6 +100,7 @@ qcrypto_block_qcow_open(QCryptoBlock *block,
                         QCryptoBlockReadFunc readfunc G_GNUC_UNUSED,
                         void *opaque G_GNUC_UNUSED,
                         unsigned int flags,
+                        size_t n_threads,
                         Error **errp)
 {
     if (flags & QCRYPTO_BLOCK_OPEN_NO_IO) {
@@ -112,8 +114,8 @@ qcrypto_block_qcow_open(QCryptoBlock *block,
                        optprefix ? optprefix : "");
             return -1;
         }
-        return qcrypto_block_qcow_init(block,
-                                       options->u.qcow.key_secret, errp);
+        return qcrypto_block_qcow_init(block, options->u.qcow.key_secret,
+                                       n_threads, errp);
     }
 }
 
@@ -133,7 +135,7 @@ qcrypto_block_qcow_create(QCryptoBlock *block,
         return -1;
     }
     /* QCow2 has no special header, since everything is hardwired */
-    return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, errp);
+    return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, 1, errp);
 }
 
 
diff --git a/crypto/block.c b/crypto/block.c
index 3fe3de2ef8..d70d401f87 100644
--- a/crypto/block.c
+++ b/crypto/block.c
@@ -52,6 +52,7 @@ QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
                                  QCryptoBlockReadFunc readfunc,
                                  void *opaque,
                                  unsigned int flags,
+                                 size_t n_threads,
                                  Error **errp)
 {
     QCryptoBlock *block = g_new0(QCryptoBlock, 1);
@@ -69,11 +70,14 @@ QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
     block->driver = qcrypto_block_drivers[options->format];
 
     if (block->driver->open(block, options, optprefix,
-                            readfunc, opaque, flags, errp) < 0) {
+                            readfunc, opaque, flags, n_threads, errp) < 0)
+    {
         g_free(block);
         return NULL;
     }
 
+    qemu_mutex_init(&block->mutex);
+
     return block;
 }
 
@@ -105,6 +109,8 @@ QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options,
         return NULL;
     }
 
+    qemu_mutex_init(&block->mutex);
+
     return block;
 }
 
@@ -148,12 +154,97 @@ int qcrypto_block_encrypt(QCryptoBlock *block,
 
 QCryptoCipher *qcrypto_block_get_cipher(QCryptoBlock *block)
 {
-    return block->cipher;
+    /* Ciphers should be accessed through pop/push method to be thread-safe.
+     * Better, they should not be accessed externally at all (note, that
+     * pop/push are static functions)
+     * This function is used only in test with one thread (it's safe to skip
+     * pop/push interface), so it's enough to assert it here:
+     */
+    assert(block->n_ciphers <= 1);
+    return block->ciphers ? block->ciphers[0] : NULL;
+}
+
+
+static QCryptoCipher *qcrypto_block_pop_cipher(QCryptoBlock *block)
+{
+    QCryptoCipher *cipher;
+
+    qemu_mutex_lock(&block->mutex);
+
+    assert(block->n_free_ciphers > 0);
+    block->n_free_ciphers--;
+    cipher = block->ciphers[block->n_free_ciphers];
+
+    qemu_mutex_unlock(&block->mutex);
+
+    return cipher;
+}
+
+
+static void qcrypto_block_push_cipher(QCryptoBlock *block,
+                                      QCryptoCipher *cipher)
+{
+    qemu_mutex_lock(&block->mutex);
+
+    assert(block->n_free_ciphers < block->n_ciphers);
+    block->ciphers[block->n_free_ciphers] = cipher;
+    block->n_free_ciphers++;
+
+    qemu_mutex_unlock(&block->mutex);
+}
+
+
+int qcrypto_block_init_cipher(QCryptoBlock *block,
+                              QCryptoCipherAlgorithm alg,
+                              QCryptoCipherMode mode,
+                              const uint8_t *key, size_t nkey,
+                              size_t n_threads, Error **errp)
+{
+    size_t i;
+
+    assert(!block->ciphers && !block->n_ciphers && !block->n_free_ciphers);
+
+    block->ciphers = g_new0(QCryptoCipher *, n_threads);
+
+    for (i = 0; i < n_threads; i++) {
+        block->ciphers[i] = qcrypto_cipher_new(alg, mode, key, nkey, errp);
+        if (!block->ciphers[i]) {
+            qcrypto_block_free_cipher(block);
+            return -1;
+        }
+        block->n_ciphers++;
+        block->n_free_ciphers++;
+    }
+
+    return 0;
 }
 
 
+void qcrypto_block_free_cipher(QCryptoBlock *block)
+{
+    size_t i;
+
+    if (!block->ciphers) {
+        return;
+    }
+
+    assert(block->n_ciphers == block->n_free_ciphers);
+
+    for (i = 0; i < block->n_ciphers; i++) {
+        qcrypto_cipher_free(block->ciphers[i]);
+    }
+
+    g_free(block->ciphers);
+    block->ciphers = NULL;
+    block->n_ciphers = block->n_free_ciphers = 0;
+}
+
 QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block)
 {
+    /* ivgen should be accessed under mutex. However, this function is used only
+     * in test with one thread, so it's enough to assert it here:
+     */
+    assert(block->n_ciphers <= 1);
     return block->ivgen;
 }
 
@@ -184,8 +275,9 @@ void qcrypto_block_free(QCryptoBlock *block)
 
     block->driver->cleanup(block);
 
-    qcrypto_cipher_free(block->cipher);
+    qcrypto_block_free_cipher(block);
     qcrypto_ivgen_free(block->ivgen);
+    qemu_mutex_destroy(&block->mutex);
     g_free(block);
 }
 
@@ -199,6 +291,7 @@ typedef int (*QCryptoCipherEncDecFunc)(QCryptoCipher *cipher,
 static int do_qcrypto_block_cipher_encdec(QCryptoCipher *cipher,
                                           size_t niv,
                                           QCryptoIVGen *ivgen,
+                                          QemuMutex *ivgen_mutex,
                                           int sectorsize,
                                           uint64_t offset,
                                           uint8_t *buf,
@@ -218,10 +311,15 @@ static int do_qcrypto_block_cipher_encdec(QCryptoCipher *cipher,
     while (len > 0) {
         size_t nbytes;
         if (niv) {
-            if (qcrypto_ivgen_calculate(ivgen,
-                                        startsector,
-                                        iv, niv,
-                                        errp) < 0) {
+            if (ivgen_mutex) {
+                qemu_mutex_lock(ivgen_mutex);
+            }
+            ret = qcrypto_ivgen_calculate(ivgen, startsector, iv, niv, errp);
+            if (ivgen_mutex) {
+                qemu_mutex_unlock(ivgen_mutex);
+            }
+
+            if (ret < 0) {
                 goto cleanup;
             }
 
@@ -258,7 +356,7 @@ int qcrypto_block_cipher_decrypt_helper(QCryptoCipher *cipher,
                                         size_t len,
                                         Error **errp)
 {
-    return do_qcrypto_block_cipher_encdec(cipher, niv, ivgen, sectorsize,
+    return do_qcrypto_block_cipher_encdec(cipher, niv, ivgen, NULL, sectorsize,
                                           offset, buf, len,
                                           qcrypto_cipher_decrypt, errp);
 }
@@ -273,12 +371,11 @@ int qcrypto_block_cipher_encrypt_helper(QCryptoCipher *cipher,
                                         size_t len,
                                         Error **errp)
 {
-    return do_qcrypto_block_cipher_encdec(cipher, niv, ivgen, sectorsize,
+    return do_qcrypto_block_cipher_encdec(cipher, niv, ivgen, NULL, sectorsize,
                                           offset, buf, len,
                                           qcrypto_cipher_encrypt, errp);
 }
 
-
 int qcrypto_block_decrypt_helper(QCryptoBlock *block,
                                  int sectorsize,
                                  uint64_t offset,
@@ -286,12 +383,17 @@ int qcrypto_block_decrypt_helper(QCryptoBlock *block,
                                  size_t len,
                                  Error **errp)
 {
-    return do_qcrypto_block_cipher_encdec(block->cipher, block->niv,
-                                          block->ivgen,
-                                          sectorsize, offset, buf, len,
-                                          qcrypto_cipher_decrypt, errp);
-}
+    int ret;
+    QCryptoCipher *cipher = qcrypto_block_pop_cipher(block);
 
+    ret = do_qcrypto_block_cipher_encdec(cipher, block->niv, block->ivgen,
+                                         &block->mutex, sectorsize, offset, buf,
+                                         len, qcrypto_cipher_decrypt, errp);
+
+    qcrypto_block_push_cipher(block, cipher);
+
+    return ret;
+}
 
 int qcrypto_block_encrypt_helper(QCryptoBlock *block,
                                  int sectorsize,
@@ -300,8 +402,14 @@ int qcrypto_block_encrypt_helper(QCryptoBlock *block,
                                  size_t len,
                                  Error **errp)
 {
-    return do_qcrypto_block_cipher_encdec(block->cipher, block->niv,
-                                          block->ivgen,
-                                          sectorsize, offset, buf, len,
-                                          qcrypto_cipher_encrypt, errp);
+    int ret;
+    QCryptoCipher *cipher = qcrypto_block_pop_cipher(block);
+
+    ret = do_qcrypto_block_cipher_encdec(cipher, block->niv, block->ivgen,
+                                         &block->mutex, sectorsize, offset, buf,
+                                         len, qcrypto_cipher_encrypt, errp);
+
+    qcrypto_block_push_cipher(block, cipher);
+
+    return ret;
 }
diff --git a/crypto/blockpriv.h b/crypto/blockpriv.h
index 438c08bec2..5438e822fd 100644
--- a/crypto/blockpriv.h
+++ b/crypto/blockpriv.h
@@ -22,6 +22,7 @@
 #define QCRYPTO_BLOCKPRIV_H
 
 #include "crypto/block.h"
+#include "qemu/thread.h"
 
 typedef struct QCryptoBlockDriver QCryptoBlockDriver;
 
@@ -31,8 +32,12 @@ struct QCryptoBlock {
     const QCryptoBlockDriver *driver;
     void *opaque;
 
-    QCryptoCipher *cipher;
+    QCryptoCipher **ciphers;
+    size_t n_ciphers;
+    size_t n_free_ciphers;
     QCryptoIVGen *ivgen;
+    QemuMutex mutex;
+
     QCryptoHashAlgorithm kdfhash;
     size_t niv;
     uint64_t payload_offset; /* In bytes */
@@ -46,6 +51,7 @@ struct QCryptoBlockDriver {
                 QCryptoBlockReadFunc readfunc,
                 void *opaque,
                 unsigned int flags,
+                size_t n_threads,
                 Error **errp);
 
     int (*create)(QCryptoBlock *block,
@@ -110,4 +116,12 @@ int qcrypto_block_encrypt_helper(QCryptoBlock *block,
                                  size_t len,
                                  Error **errp);
 
+int qcrypto_block_init_cipher(QCryptoBlock *block,
+                              QCryptoCipherAlgorithm alg,
+                              QCryptoCipherMode mode,
+                              const uint8_t *key, size_t nkey,
+                              size_t n_threads, Error **errp);
+
+void qcrypto_block_free_cipher(QCryptoBlock *block);
+
 #endif /* QCRYPTO_BLOCKPRIV_H */
diff --git a/include/crypto/block.h b/include/crypto/block.h
index cd18f46d56..e729d5bd66 100644
--- a/include/crypto/block.h
+++ b/include/crypto/block.h
@@ -75,6 +75,7 @@ typedef enum {
  * @readfunc: callback for reading data from the volume
  * @opaque: data to pass to @readfunc
  * @flags: bitmask of QCryptoBlockOpenFlags values
+ * @n_threads: allow concurrent I/O from up to @n_threads threads
  * @errp: pointer to a NULL-initialized error object
  *
  * Create a new block encryption object for an existing
@@ -107,6 +108,7 @@ QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
                                  QCryptoBlockReadFunc readfunc,
                                  void *opaque,
                                  unsigned int flags,
+                                 size_t n_threads,
                                  Error **errp);
 
 /**
diff --git a/tests/test-crypto-block.c b/tests/test-crypto-block.c
index fae4ffc453..d309d044ef 100644
--- a/tests/test-crypto-block.c
+++ b/tests/test-crypto-block.c
@@ -305,6 +305,7 @@ static void test_block(gconstpointer opaque)
                              test_block_read_func,
                              &header,
                              0,
+                             1,
                              NULL);
     g_assert(blk == NULL);
 
@@ -313,6 +314,7 @@ static void test_block(gconstpointer opaque)
                              test_block_read_func,
                              &header,
                              QCRYPTO_BLOCK_OPEN_NO_IO,
+                             1,
                              &error_abort);
 
     g_assert(qcrypto_block_get_cipher(blk) == NULL);
@@ -327,6 +329,7 @@ static void test_block(gconstpointer opaque)
                              test_block_read_func,
                              &header,
                              0,
+                             1,
                              &error_abort);
     g_assert(blk);