[Qemu-devel] [PATCH v1 09/15] qcow2: make qcow2_encrypt_sectors encrypt in place

["Daniel P. Berrange" <berrange@redhat.com>]

Instead of requiring separate input/output buffers for
encrypting data, change qcow2_encrypt_sectors() to assume
use of a single buffer, encrypting in place. The current
callers all used the same buffer for input/output already.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 block/qcow2-cluster.c | 17 +++++------------
 block/qcow2.c         |  5 ++---
 block/qcow2.h         |  3 +--
 3 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 34112c3..f5bc4f2 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -341,12 +341,8 @@ static int count_contiguous_clusters_by_type(int nb_clusters,
     return i;
 }
 
-/* The crypt function is compatible with the linux cryptoloop
-   algorithm for < 4 GB images. NOTE: out_buf == in_buf is
-   supported */
 int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
-                          uint8_t *out_buf, const uint8_t *in_buf,
-                          int nb_sectors, bool enc,
+                          uint8_t *buf, int nb_sectors, bool enc,
                           Error **errp)
 {
     union {
@@ -366,14 +362,12 @@ int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
         }
         if (enc) {
             ret = qcrypto_cipher_encrypt(s->cipher,
-                                         in_buf,
-                                         out_buf,
+                                         buf, buf,
                                          512,
                                          errp);
         } else {
             ret = qcrypto_cipher_decrypt(s->cipher,
-                                         in_buf,
-                                         out_buf,
+                                         buf, buf,
                                          512,
                                          errp);
         }
@@ -381,8 +375,7 @@ int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
             return -1;
         }
         sector_num++;
-        in_buf += 512;
-        out_buf += 512;
+        buf += 512;
     }
     return 0;
 }
@@ -430,7 +423,7 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
         Error *err = NULL;
         assert(s->cipher);
         if (qcow2_encrypt_sectors(s, start_sect + n_start,
-                                  iov.iov_base, iov.iov_base, n,
+                                  iov.iov_base, n,
                                   true, &err) < 0) {
             ret = -EIO;
             error_free(err);
diff --git a/block/qcow2.c b/block/qcow2.c
index 1789af4..c0fc259 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1504,7 +1504,7 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
                 assert(s->cipher);
                 Error *err = NULL;
                 if (qcow2_encrypt_sectors(s, sector_num,  cluster_data,
-                                          cluster_data, cur_nr_sectors, false,
+                                          cur_nr_sectors, false,
                                           &err) < 0) {
                     error_free(err);
                     ret = -EIO;
@@ -1604,8 +1604,7 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
             qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
 
             if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
-                                      cluster_data, cur_nr_sectors,
-                                      true, &err) < 0) {
+                                      cur_nr_sectors, true, &err) < 0) {
                 error_free(err);
                 ret = -EIO;
                 goto fail;
diff --git a/block/qcow2.h b/block/qcow2.h
index a063a3c..ae04285 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -540,8 +540,7 @@ int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
 void qcow2_l2_cache_reset(BlockDriverState *bs);
 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
-                          uint8_t *out_buf, const uint8_t *in_buf,
-                          int nb_sectors, bool enc, Error **errp);
+                          uint8_t *buf, int nb_sectors, bool enc, Error **errp);
 
 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
     int *num, uint64_t *cluster_offset);
-- 
2.5.0