Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2020-02-06' into staging

Block patches:
- Drop BDRV_SECTOR_SIZE from qcow2
- Allow Python iotests to be added to the auto group
  (and add some)
- Fix for the backup job
- Fix memleak in bdrv_refresh_filename()
- Use GStrings in two places for greater efficiency (than manually
  handling string allocation)

# gpg: Signature made Thu 06 Feb 2020 12:50:14 GMT
# gpg:                using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg:                issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2020-02-06:
  iotests: add test for backup-top failure on permission activation
  block/backup-top: fix failure path
  qcow2: Use BDRV_SECTOR_SIZE instead of the hardcoded value
  qcow2: Don't require aligned offsets in qcow2_co_copy_range_from()
  qcow2: Use bs->bl.request_alignment when updating an L1 entry
  qcow2: Tighten cluster_offset alignment assertions
  qcow2: Don't round the L1 table allocation up to the sector size
  iotests: Enable more tests in the 'auto' group to improve test coverage
  iotests: Skip Python-based tests if QEMU does not support virtio-blk
  iotests: Check for the availability of the required devices in 267 and 127
  iotests: Test 183 does not work on macOS and OpenBSD
  iotests: Test 041 only works on certain systems
  iotests: remove 'linux' from default supported platforms
  qcow2: Use a GString in report_unsupported_feature()
  block: fix memleaks in bdrv_refresh_filename
  block: Use a GString in bdrv_perm_names()
  qcow2: Assert that host cluster offsets fit in L2 table entries

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

16 files changed, 220 insertions, 73 deletions

diff --git a/block.c b/block.c
index 6c2b2bd2e2..9c810534d6 100644
--- a/block.c
+++ b/block.c
@@ -1998,18 +1998,19 @@ char *bdrv_perm_names(uint64_t perm)
         { 0, NULL }
     };
 
-    char *result = g_strdup("");
+    GString *result = g_string_sized_new(30);
     struct perm_name *p;
 
     for (p = permissions; p->name; p++) {
         if (perm & p->perm) {
-            char *old = result;
-            result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name);
-            g_free(old);
+            if (result->len > 0) {
+                g_string_append(result, ", ");
+            }
+            g_string_append(result, p->name);
         }
     }
 
-    return result;
+    return g_string_free(result, FALSE);
 }
 
 /*
@@ -6441,6 +6442,7 @@ void bdrv_refresh_filename(BlockDriverState *bs)
                 child->bs->exact_filename);
         pstrcpy(bs->filename, sizeof(bs->filename), child->bs->filename);
 
+        qobject_unref(bs->full_open_options);
         bs->full_open_options = qobject_ref(child->bs->full_open_options);
 
         return;
diff --git a/block/backup-top.c b/block/backup-top.c
index 9aed2eb4c0..fa78f3256d 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -190,6 +190,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
     BlockDriverState *top = bdrv_new_open_driver(&bdrv_backup_top_filter,
                                                  filter_node_name,
                                                  BDRV_O_RDWR, errp);
+    bool appended = false;
 
     if (!top) {
         return NULL;
@@ -212,8 +213,9 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
     bdrv_append(top, source, &local_err);
     if (local_err) {
         error_prepend(&local_err, "Cannot append backup-top filter: ");
-        goto append_failed;
+        goto fail;
     }
+    appended = true;
 
     /*
      * bdrv_append() finished successfully, now we can require permissions
@@ -224,14 +226,14 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
     if (local_err) {
         error_prepend(&local_err,
                       "Cannot set permissions for backup-top filter: ");
-        goto failed_after_append;
+        goto fail;
     }
 
     state->bcs = block_copy_state_new(top->backing, state->target,
                                       cluster_size, write_flags, &local_err);
     if (local_err) {
         error_prepend(&local_err, "Cannot create block-copy-state: ");
-        goto failed_after_append;
+        goto fail;
     }
     *bcs = state->bcs;
 
@@ -239,14 +241,15 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
 
     return top;
 
-failed_after_append:
-    state->active = false;
-    bdrv_backup_top_drop(top);
+fail:
+    if (appended) {
+        state->active = false;
+        bdrv_backup_top_drop(top);
+    } else {
+        bdrv_unref(top);
+    }
 
-append_failed:
     bdrv_drained_end(source);
-    bdrv_unref_child(top, state->target);
-    bdrv_unref(top);
     error_propagate(errp, local_err);
 
     return NULL;
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 8982b7b762..1947f13a2d 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -124,12 +124,11 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
 #endif
 
     new_l1_size2 = sizeof(uint64_t) * new_l1_size;
-    new_l1_table = qemu_try_blockalign(bs->file->bs,
-                                       ROUND_UP(new_l1_size2, 512));
+    new_l1_table = qemu_try_blockalign(bs->file->bs, new_l1_size2);
     if (new_l1_table == NULL) {
         return -ENOMEM;
     }
-    memset(new_l1_table, 0, ROUND_UP(new_l1_size2, 512));
+    memset(new_l1_table, 0, new_l1_size2);
 
     if (s->l1_size) {
         memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
@@ -217,26 +216,31 @@ static int l2_load(BlockDriverState *bs, uint64_t offset,
 }
 
 /*
- * Writes one sector of the L1 table to the disk (can't update single entries
- * and we really don't want bdrv_pread to perform a read-modify-write)
+ * Writes an L1 entry to disk (note that depending on the alignment
+ * requirements this function may write more that just one entry in
+ * order to prevent bdrv_pwrite from performing a read-modify-write)
  */
-#define L1_ENTRIES_PER_SECTOR (512 / 8)
 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
 {
     BDRVQcow2State *s = bs->opaque;
-    uint64_t buf[L1_ENTRIES_PER_SECTOR] = { 0 };
     int l1_start_index;
     int i, ret;
+    int bufsize = MAX(sizeof(uint64_t),
+                      MIN(bs->file->bs->bl.request_alignment, s->cluster_size));
+    int nentries = bufsize / sizeof(uint64_t);
+    g_autofree uint64_t *buf = g_try_new0(uint64_t, nentries);
 
-    l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
-    for (i = 0; i < L1_ENTRIES_PER_SECTOR && l1_start_index + i < s->l1_size;
-         i++)
-    {
+    if (buf == NULL) {
+        return -ENOMEM;
+    }
+
+    l1_start_index = QEMU_ALIGN_DOWN(l1_index, nentries);
+    for (i = 0; i < MIN(nentries, s->l1_size - l1_start_index); i++) {
         buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
     }
 
     ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
-            s->l1_table_offset + 8 * l1_start_index, sizeof(buf), false);
+            s->l1_table_offset + 8 * l1_start_index, bufsize, false);
     if (ret < 0) {
         return ret;
     }
@@ -244,7 +248,7 @@ int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
     BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
     ret = bdrv_pwrite_sync(bs->file,
                            s->l1_table_offset + 8 * l1_start_index,
-                           buf, sizeof(buf));
+                           buf, bufsize);
     if (ret < 0) {
         return ret;
     }
@@ -777,6 +781,10 @@ int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
         (cluster_offset + compressed_size - 1) / QCOW2_COMPRESSED_SECTOR_SIZE -
         (cluster_offset / QCOW2_COMPRESSED_SECTOR_SIZE);
 
+    /* The offset and size must fit in their fields of the L2 table entry */
+    assert((cluster_offset & s->cluster_offset_mask) == cluster_offset);
+    assert((nb_csectors & s->csize_mask) == nb_csectors);
+
     cluster_offset |= QCOW_OFLAG_COMPRESSED |
                       ((uint64_t)nb_csectors << s->csize_shift);
 
@@ -972,6 +980,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
 
     assert(l2_index + m->nb_clusters <= s->l2_slice_size);
     for (i = 0; i < m->nb_clusters; i++) {
+        uint64_t offset = cluster_offset + (i << s->cluster_bits);
         /* if two concurrent writes happen to the same unallocated cluster
          * each write allocates separate cluster and writes data concurrently.
          * The first one to complete updates l2 table with pointer to its
@@ -982,8 +991,10 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
             old_cluster[j++] = l2_slice[l2_index + i];
         }
 
-        l2_slice[l2_index + i] = cpu_to_be64((cluster_offset +
-                    (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
+        /* The offset must fit in the offset field of the L2 table entry */
+        assert((offset & L2E_OFFSET_MASK) == offset);
+
+        l2_slice[l2_index + i] = cpu_to_be64(offset | QCOW_OFLAG_COPIED);
      }
 
 
@@ -1913,6 +1924,9 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
                         goto fail;
                     }
 
+                    /* The offset must fit in the offset field */
+                    assert((offset & L2E_OFFSET_MASK) == offset);
+
                     if (l2_refcount > 1) {
                         /* For shared L2 tables, set the refcount accordingly
                          * (it is already 1 and needs to be l2_refcount) */
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index f67ac6b2d8..c963bc8de1 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1262,7 +1262,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
      * l1_table_offset when it is the current s->l1_table_offset! Be careful
      * when changing this! */
     if (l1_table_offset != s->l1_table_offset) {
-        l1_table = g_try_malloc0(ROUND_UP(l1_size2, 512));
+        l1_table = g_try_malloc0(l1_size2);
         if (l1_size2 && l1_table == NULL) {
             ret = -ENOMEM;
             goto fail;
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 5ab64da1ec..82c32d4c9b 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -1024,8 +1024,7 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
         return ret;
     }
     new_l1_bytes = sn->l1_size * sizeof(uint64_t);
-    new_l1_table = qemu_try_blockalign(bs->file->bs,
-                                       ROUND_UP(new_l1_bytes, 512));
+    new_l1_table = qemu_try_blockalign(bs->file->bs, new_l1_bytes);
     if (new_l1_table == NULL) {
         return -ENOMEM;
     }
diff --git a/block/qcow2.c b/block/qcow2.c
index cef9d72b3a..ef96606f8d 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -453,16 +453,15 @@ static void cleanup_unknown_header_ext(BlockDriverState *bs)
 static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
                                        uint64_t mask)
 {
-    char *features = g_strdup("");
-    char *old;
+    g_autoptr(GString) features = g_string_sized_new(60);
 
     while (table && table->name[0] != '\0') {
         if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
             if (mask & (1ULL << table->bit)) {
-                old = features;
-                features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
-                                           table->name);
-                g_free(old);
+                if (features->len > 0) {
+                    g_string_append(features, ", ");
+                }
+                g_string_append_printf(features, "%.46s", table->name);
                 mask &= ~(1ULL << table->bit);
             }
         }
@@ -470,14 +469,14 @@ static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
     }
 
     if (mask) {
-        old = features;
-        features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
-                                   old, *old ? ", " : "", mask);
-        g_free(old);
+        if (features->len > 0) {
+            g_string_append(features, ", ");
+        }
+        g_string_append_printf(features,
+                               "Unknown incompatible feature: %" PRIx64, mask);
     }
 
-    error_setg(errp, "Unsupported qcow2 feature(s): %s", features);
-    g_free(features);
+    error_setg(errp, "Unsupported qcow2 feature(s): %s", features->str);
 }
 
 /*
@@ -1492,7 +1491,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
 
     if (s->l1_size > 0) {
         s->l1_table = qemu_try_blockalign(bs->file->bs,
-            ROUND_UP(s->l1_size * sizeof(uint64_t), 512));
+                                          s->l1_size * sizeof(uint64_t));
         if (s->l1_table == NULL) {
             error_setg(errp, "Could not allocate L1 table");
             ret = -ENOMEM;
@@ -2168,10 +2167,7 @@ static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs,
                                           offset, bytes, qiov, qiov_offset);
 
     case QCOW2_CLUSTER_NORMAL:
-        if ((file_cluster_offset & 511) != 0) {
-            return -EIO;
-        }
-
+        assert(offset_into_cluster(s, file_cluster_offset) == 0);
         if (bs->encrypted) {
             return qcow2_co_preadv_encrypted(bs, file_cluster_offset,
                                              offset, bytes, qiov, qiov_offset);
@@ -2507,7 +2503,7 @@ static coroutine_fn int qcow2_co_pwritev_part(
             goto out_locked;
         }
 
-        assert((cluster_offset & 511) == 0);
+        assert(offset_into_cluster(s, cluster_offset) == 0);
 
         ret = qcow2_pre_write_overlap_check(bs, 0,
                                             cluster_offset + offset_in_cluster,
@@ -3276,7 +3272,8 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
 
     /* Validate options and set default values */
     if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) {
-        error_setg(errp, "Image size must be a multiple of 512 bytes");
+        error_setg(errp, "Image size must be a multiple of %u bytes",
+                   (unsigned) BDRV_SECTOR_SIZE);
         ret = -EINVAL;
         goto out;
     }
@@ -3832,10 +3829,6 @@ qcow2_co_copy_range_from(BlockDriverState *bs,
         case QCOW2_CLUSTER_NORMAL:
             child = s->data_file;
             copy_offset += offset_into_cluster(s, src_offset);
-            if ((copy_offset & 511) != 0) {
-                ret = -EIO;
-                goto out;
-            }
             break;
 
         default:
@@ -3897,7 +3890,7 @@ qcow2_co_copy_range_to(BlockDriverState *bs,
             goto fail;
         }
 
-        assert((cluster_offset & 511) == 0);
+        assert(offset_into_cluster(s, cluster_offset) == 0);
 
         ret = qcow2_pre_write_overlap_check(bs, 0,
                 cluster_offset + offset_in_cluster, cur_bytes, true);
@@ -3954,8 +3947,9 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
         return -ENOTSUP;
     }
 
-    if (offset & 511) {
-        error_setg(errp, "The new size must be a multiple of 512");
+    if (!QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE)) {
+        error_setg(errp, "The new size must be a multiple of %u",
+                   (unsigned) BDRV_SECTOR_SIZE);
         return -EINVAL;
     }
 
diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
index c07437fda1..0181f7a9b6 100755
--- a/tests/qemu-iotests/041
+++ b/tests/qemu-iotests/041
@@ -1134,4 +1134,5 @@ class TestOrphanedSource(iotests.QMPTestCase):
 
 if __name__ == '__main__':
     iotests.main(supported_fmts=['qcow2', 'qed'],
-                 supported_protocols=['file'])
+                 supported_protocols=['file'],
+                 supported_platforms=['linux', 'freebsd', 'netbsd', 'openbsd'])
diff --git a/tests/qemu-iotests/127 b/tests/qemu-iotests/127
index b64926ab31..a4fc866038 100755
--- a/tests/qemu-iotests/127
+++ b/tests/qemu-iotests/127
@@ -43,6 +43,8 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 _supported_fmt qcow2
 _supported_proto file
 
+_require_devices virtio-scsi scsi-hd
+
 IMG_SIZE=64K
 
 _make_test_img $IMG_SIZE
diff --git a/tests/qemu-iotests/183 b/tests/qemu-iotests/183
index 64621617f5..acdbefa310 100755
--- a/tests/qemu-iotests/183
+++ b/tests/qemu-iotests/183
@@ -42,6 +42,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 . ./common.filter
 . ./common.qemu
 
+_supported_os Linux FreeBSD NetBSD
 _supported_fmt qcow2 raw qed quorum
 _supported_proto file
 
diff --git a/tests/qemu-iotests/267 b/tests/qemu-iotests/267
index c296877168..3146273eef 100755
--- a/tests/qemu-iotests/267
+++ b/tests/qemu-iotests/267
@@ -46,6 +46,8 @@ _require_drivers copy-on-read
 # and generally impossible with external data files
 _unsupported_imgopts 'refcount_bits=1[^0-9]' data_file
 
+_require_devices virtio-blk
+
 do_run_qemu()
 {
     echo Testing: "$@"
diff --git a/tests/qemu-iotests/283 b/tests/qemu-iotests/283
new file mode 100644
index 0000000000..293e557bd9
--- /dev/null
+++ b/tests/qemu-iotests/283
@@ -0,0 +1,92 @@
+#!/usr/bin/env python
+#
+# Test for backup-top filter permission activation failure
+#
+# Copyright (c) 2019 Virtuozzo International GmbH.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import iotests
+
+# The test is unrelated to formats, restrict it to qcow2 to avoid extra runs
+iotests.verify_image_format(supported_fmts=['qcow2'])
+
+size = 1024 * 1024
+
+""" Test description
+
+When performing a backup, all writes on the source subtree must go through the
+backup-top filter so it can copy all data to the target before it is changed.
+backup-top filter is appended above source node, to achieve this thing, so all
+parents of source node are handled. A configuration with side parents of source
+sub-tree with write permission is unsupported (we'd have append several
+backup-top filter like nodes to handle such parents). The test create an
+example of such configuration and checks that a backup is then not allowed
+(blockdev-backup command should fail).
+
+The configuration:
+
+    ┌────────┐  target  ┌─────────────┐
+    │ target │ ◀─────── │ backup_top  │
+    └────────┘          └─────────────┘
+                            │
+                            │ backing
+                            ▼
+                        ┌─────────────┐
+                        │   source    │
+                        └─────────────┘
+                            │
+                            │ file
+                            ▼
+                        ┌─────────────┐  write perm   ┌───────┐
+                        │    base     │ ◀──────────── │ other │
+                        └─────────────┘               └───────┘
+
+On activation (see .active field of backup-top state in block/backup-top.c),
+backup-top is going to unshare write permission on its source child. Write
+unsharing will be propagated to the "source->base" link and will conflict with
+other node write permission. So permission update will fail and backup job will
+not be started.
+
+Note, that the only thing which prevents backup of running on such
+configuration is default permission propagation scheme. It may be altered by
+different block drivers, so backup will run in invalid configuration. But
+something is better than nothing. Also, before the previous commit (commit
+preceding this test creation), starting backup on such configuration led to
+crash, so current "something" is a lot better, and this test actual goal is
+to check that crash is fixed :)
+"""
+
+vm = iotests.VM()
+vm.launch()
+
+vm.qmp_log('blockdev-add', **{'node-name': 'target', 'driver': 'null-co'})
+
+vm.qmp_log('blockdev-add', **{
+    'node-name': 'source',
+    'driver': 'blkdebug',
+    'image': {'node-name': 'base', 'driver': 'null-co', 'size': size}
+})
+
+vm.qmp_log('blockdev-add', **{
+    'node-name': 'other',
+    'driver': 'blkdebug',
+    'image': 'base',
+    'take-child-perms': ['write']
+})
+
+vm.qmp_log('blockdev-backup', sync='full', device='source', target='target')
+
+vm.shutdown()
diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out
new file mode 100644
index 0000000000..daaf5828c1
--- /dev/null
+++ b/tests/qemu-iotests/283.out
@@ -0,0 +1,8 @@
+{"execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "target"}}
+{"return": {}}
+{"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": {"driver": "null-co", "node-name": "base", "size": 1048576}, "node-name": "source"}}
+{"return": {}}
+{"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": "base", "node-name": "other", "take-child-perms": ["write"]}}
+{"return": {}}
+{"execute": "blockdev-backup", "arguments": {"device": "source", "sync": "full", "target": "target"}}
+{"error": {"class": "GenericError", "desc": "Cannot set permissions for backup-top filter: Conflicts with use by other as 'image', which uses 'write' on base"}}
diff --git a/tests/qemu-iotests/check b/tests/qemu-iotests/check
index 39ed5bc1be..fff5fa956a 100755
--- a/tests/qemu-iotests/check
+++ b/tests/qemu-iotests/check
@@ -655,7 +655,15 @@ fi
 python_usable=false
 if $PYTHON -c 'import sys; sys.exit(0 if sys.version_info >= (3,6) else 1)'
 then
-    python_usable=true
+    # Our python framework also requires virtio-blk
+    if "$QEMU_PROG" -M none -device help | grep -q virtio-blk >/dev/null 2>&1
+    then
+        python_usable=true
+    else
+        python_unusable_because="Missing virtio-blk in QEMU binary"
+    fi
+else
+    python_unusable_because="Unsupported Python version"
 fi
 
 default_machine=$($QEMU_PROG -machine help | sed -n '/(default)/ s/ .*//p')
@@ -843,7 +851,7 @@ do
                 run_command="$PYTHON $seq"
             else
                 run_command="false"
-                echo "Unsupported Python version" > $seq.notrun
+                echo "$python_unusable_because" > $seq.notrun
             fi
         else
             run_command="./$seq"
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 9ccde32634..8a6366c09d 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -713,5 +713,19 @@ _require_large_file()
     rm "$TEST_IMG"
 }
 
+# Check that a set of devices is available in the QEMU binary
+#
+_require_devices()
+{
+    available=$($QEMU -M none -device help | \
+                grep ^name | sed -e 's/^name "//' -e 's/".*$//')
+    for device
+    do
+        if ! echo "$available" | grep -q "$device" ; then
+            _notrun "$device not available"
+        fi
+    done
+}
+
 # make sure this script returns success
 true
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index e041cc1ee3..1904223020 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -51,7 +51,7 @@
 027 rw auto quick
 028 rw backing quick
 029 rw auto quick
-030 rw backing
+030 rw auto backing
 031 rw auto quick
 032 rw auto quick
 033 rw auto quick
@@ -61,8 +61,8 @@
 037 rw auto backing quick
 038 rw auto backing quick
 039 rw auto quick
-040 rw
-041 rw backing
+040 rw auto
+041 rw auto backing
 042 rw auto quick
 043 rw auto backing
 044 rw
@@ -148,7 +148,7 @@
 124 rw backing
 125 rw
 126 rw auto backing
-127 rw backing quick
+127 rw auto backing quick
 128 rw quick
 129 rw quick
 130 rw quick
@@ -197,7 +197,7 @@
 177 rw auto quick
 178 img
 179 rw auto quick
-181 rw migration
+181 rw auto migration
 182 rw quick
 183 rw migration
 184 rw auto quick
@@ -218,7 +218,7 @@
 200 rw
 201 rw migration
 202 rw quick
-203 rw migration
+203 rw auto migration
 204 rw quick
 205 rw quick
 206 rw
@@ -270,7 +270,7 @@
 253 rw quick
 254 rw backing quick
 255 rw quick
-256 rw quick
+256 rw auto quick
 257 rw
 258 rw quick
 260 rw quick
@@ -289,3 +289,4 @@
 279 rw backing quick
 280 rw migration quick
 281 rw quick
+283 auto quick
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 89aa2df2f3..ead04a1ab5 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -931,9 +931,14 @@ def verify_protocol(supported=[], unsupported=[]):
     if not_sup or (imgproto in unsupported):
         notrun('not suitable for this protocol: %s' % imgproto)
 
-def verify_platform(supported_oses=['linux']):
-    if True not in [sys.platform.startswith(x) for x in supported_oses]:
-        notrun('not suitable for this OS: %s' % sys.platform)
+def verify_platform(supported=None, unsupported=None):
+    if unsupported is not None:
+        if any((sys.platform.startswith(x) for x in unsupported)):
+            notrun('not suitable for this OS: %s' % sys.platform)
+
+    if supported is not None:
+        if not any((sys.platform.startswith(x) for x in supported)):
+            notrun('not suitable for this OS: %s' % sys.platform)
 
 def verify_cache_mode(supported_cache_modes=[]):
     if supported_cache_modes and (cachemode not in supported_cache_modes):
@@ -1028,7 +1033,8 @@ def execute_unittest(output, verbosity, debug):
             sys.stderr.write(out)
 
 def execute_test(test_function=None,
-                 supported_fmts=[], supported_oses=['linux'],
+                 supported_fmts=[],
+                 supported_platforms=None,
                  supported_cache_modes=[], supported_aio_modes={},
                  unsupported_fmts=[], supported_protocols=[],
                  unsupported_protocols=[]):
@@ -1046,7 +1052,7 @@ def execute_test(test_function=None,
     verbosity = 1
     verify_image_format(supported_fmts, unsupported_fmts)
     verify_protocol(supported_protocols, unsupported_protocols)
-    verify_platform(supported_oses)
+    verify_platform(supported=supported_platforms)
     verify_cache_mode(supported_cache_modes)
     verify_aio_mode(supported_aio_modes)