diff --git a/block/raw-posix.c b/block/raw-posix.c
index f0b4488d1e..24d85826c4 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -503,6 +503,14 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
         error_setg_errno(errp, -ret, "Could not set AIO state");
         goto fail;
     }
+    if (!s->use_aio && (bdrv_flags & BDRV_O_NATIVE_AIO)) {
+        error_printf("WARNING: aio=native was specified for '%s', but "
+                     "it requires cache.direct=on, which was not "
+                     "specified. Falling back to aio=threads.\n"
+                     "         This will become an error condition in "
+                     "future QEMU versions.\n",
+                     bs->filename);
+    }
 #endif
 
     s->has_discard = true;
@@ -2387,6 +2395,8 @@ static int floppy_open(BlockDriverState *bs, QDict *options, int flags,
     s->fd = -1;
     s->fd_media_changed = 1;
 
+    error_report("Host floppy pass-through is deprecated");
+    error_printf("Support for it will be removed in a future release.\n");
     return 0;
 }
 
diff --git a/blockdev.c b/blockdev.c
index 0b509854b0..fbb3a79978 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1574,14 +1574,14 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
 
     blk = blk_by_name(backup->device);
     if (!blk) {
-        error_set(errp, QERR_DEVICE_NOT_FOUND, backup->device);
+        error_setg(errp, "Device '%s' not found", backup->device);
         return;
     }
     bs = blk_bs(blk);
 
     blk = blk_by_name(backup->target);
     if (!blk) {
-        error_set(errp, QERR_DEVICE_NOT_FOUND, backup->target);
+        error_setg(errp, "Device '%s' not found", backup->target);
         return;
     }
     target = blk_bs(blk);
@@ -2421,7 +2421,7 @@ void qmp_blockdev_backup(const char *device, const char *target,
 
     blk = blk_by_name(device);
     if (!blk) {
-        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        error_setg(errp, "Device '%s' not found", device);
         return;
     }
     bs = blk_bs(blk);
@@ -2431,7 +2431,7 @@ void qmp_blockdev_backup(const char *device, const char *target,
 
     blk = blk_by_name(target);
     if (!blk) {
-        error_set(errp, QERR_DEVICE_NOT_FOUND, target);
+        error_setg(errp, "Device '%s' not found", target);
         goto out;
     }
     target_bs = blk_bs(blk);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 42c885047f..f525b04355 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -218,6 +218,7 @@
 #       'host_floppy', 'http', 'https', 'nbd', 'parallels', 'qcow',
 #       'qcow2', 'raw', 'tftp', 'vdi', 'vmdk', 'vpc', 'vvfat'
 #       2.2: 'archipelago' added, 'cow' dropped
+#       2.3: 'host_floppy' deprecated
 #
 # @backing_file: #optional the name of the backing file (for copy-on-write)
 #
@@ -881,9 +882,6 @@
 #
 # For the arguments, see the documentation of BlockdevBackup.
 #
-# Returns: Nothing on success.
-#          If @device or @target is not a valid block device, DeviceNotFound.
-#
 # Since 2.3
 ##
 { 'command': 'blockdev-backup', 'data': 'BlockdevBackup' }
@@ -1245,6 +1243,7 @@
 # Drivers that are supported in block device operations.
 #
 # @host_device, @host_cdrom, @host_floppy: Since 2.1
+# @host_floppy: deprecated since 2.3
 #
 # Since: 2.0
 ##
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 8aa6dbf5d7..0125bc7928 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -736,8 +736,7 @@ devices. We describe here the usage for QEMU version >= 0.8.3.
 
 On Linux, you can directly use the host device filename instead of a
 disk image filename provided you have enough privileges to access
-it. For example, use @file{/dev/cdrom} to access to the CDROM or
-@file{/dev/fd0} for the floppy.
+it. For example, use @file{/dev/cdrom} to access to the CDROM.
 
 @table @code
 @item CD
@@ -749,6 +748,8 @@ You can specify a floppy device even if no floppy is loaded. Floppy
 removal is currently not detected accurately (if you change floppy
 without doing floppy access while the floppy is not loaded, the guest
 OS will think that the same floppy is loaded).
+Use of the host's floppy device is deprecated, and support for it will
+be removed in a future release.
 @item Hard disks
 Hard disks can be used. Normally you must specify the whole disk
 (@file{/dev/hdb} instead of @file{/dev/hdb1}) so that the guest OS can
diff --git a/qemu-options.hx b/qemu-options.hx
index 16ff72c9e8..319d971260 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -419,8 +419,7 @@ STEXI
 @item -fdb @var{file}
 @findex -fda
 @findex -fdb
-Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}). You can
-use the host floppy by using @file{/dev/fd0} as filename (@pxref{host_drives}).
+Use @var{file} as floppy disk 0/1 image (@pxref{disk_images}).
 ETEXI
 
 DEF("hda", HAS_ARG, QEMU_OPTION_hda,
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 87f0f01636..7f6876077b 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -2150,7 +2150,7 @@ Each json-object contain the following:
          - "drv": driver format name (json-string)
              - Possible values: "blkdebug", "bochs", "cloop", "dmg",
                                 "file", "file", "ftp", "ftps", "host_cdrom",
-                                "host_device", "host_floppy", "http", "https",
+                                "host_device", "http", "https",
                                 "nbd", "parallels", "qcow", "qcow2", "raw",
                                 "tftp", "vdi", "vmdk", "vpc", "vvfat"
          - "backing_file": backing file name (json-string, optional)
diff --git a/tests/qemu-iotests/055 b/tests/qemu-iotests/055
index e81d4d0d83..017a609f39 100755
--- a/tests/qemu-iotests/055
+++ b/tests/qemu-iotests/055
@@ -126,7 +126,10 @@ class TestSingleDrive(iotests.QMPTestCase):
 
     def do_test_device_not_found(self, cmd, **args):
         result = self.vm.qmp(cmd, **args)
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        if cmd == 'drive-backup':
+            self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        else:
+            self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_device_not_found(self):
         self.do_test_device_not_found('drive-backup', device='nonexistent',
@@ -364,7 +367,7 @@ class TestSingleTransaction(iotests.QMPTestCase):
                           'sync': 'full' },
             }
         ])
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
         result = self.vm.qmp('transaction', actions=[{
                 'type': 'blockdev-backup',
@@ -373,7 +376,7 @@ class TestSingleTransaction(iotests.QMPTestCase):
                           'sync': 'full' },
             }
         ])
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
         result = self.vm.qmp('transaction', actions=[{
                 'type': 'blockdev-backup',
@@ -382,7 +385,7 @@ class TestSingleTransaction(iotests.QMPTestCase):
                           'sync': 'full' },
             }
         ])
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_target_is_source(self):
         result = self.vm.qmp('transaction', actions=[{