diff mbox series

[v3,7/7] iotests: Set read-zeroes on in null block driver for Valgrind

Message ID 1561729574-530879-8-git-send-email-andrey.shinkevich@virtuozzo.com (mailing list archive)
State New, archived
Headers show
Series Allow Valgrind checking all QEMU processes | expand

Commit Message

Andrey Shinkevich June 28, 2019, 1:46 p.m. UTC 
The Valgrind tool reports about the uninitialised buffer 'buf'
instantiated on the stack of the function guess_disk_lchs().
It is revealed in the tests 051, 186, 227 and 240.
Pass 'read-zeroes=on' to the null block driver in the mentioned tests
to make them deterministic.
The output of the tests above now includes the parameter 'read-zeroes'.
So, the benchmark output files are being changed too.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 tests/qemu-iotests/051        |  10 +--
 tests/qemu-iotests/051.pc.out |  10 +--
 tests/qemu-iotests/186        |  20 +++---
 tests/qemu-iotests/186.out    | 152 +++++++++++++++++++++---------------------
 tests/qemu-iotests/227        |   4 +-
 tests/qemu-iotests/227.out    |   4 +-
 tests/qemu-iotests/240        |   8 +--
 7 files changed, 104 insertions(+), 104 deletions(-)

Comments

Andrey Shinkevich July 3, 2019, 5:31 p.m. UTC | #1 
On 28/06/2019 16:46, Andrey Shinkevich wrote:
> The Valgrind tool reports about the uninitialised buffer 'buf'
> instantiated on the stack of the function guess_disk_lchs().
> It is revealed in the tests 051, 186, 227 and 240.
> Pass 'read-zeroes=on' to the null block driver in the mentioned tests
> to make them deterministic.
> The output of the tests above now includes the parameter 'read-zeroes'.
> So, the benchmark output files are being changed too.
> 
> Suggested-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>   tests/qemu-iotests/051        |  10 +--
>   tests/qemu-iotests/051.pc.out |  10 +--
>   tests/qemu-iotests/186        |  20 +++---
>   tests/qemu-iotests/186.out    | 152 +++++++++++++++++++++---------------------
>   tests/qemu-iotests/227        |   4 +-
>   tests/qemu-iotests/227.out    |   4 +-
>   tests/qemu-iotests/240        |   8 +--
>   7 files changed, 104 insertions(+), 104 deletions(-)
> 

The Valgrind rebukes the uninitialized buffer in the find_image_format() 
of block.c when test 155 runs.
I would like to modify the python code in the mentioned test by 
replacing the backing file name:

target_backing = 'null-co://'

with

target_backing = 'json:{"read-zeroes": true, "driver": "null-co"}'

Is that the right and elegant way to do?
If so, I will add it to the next version.

Andrey
diff mbox series

Patch

diff --git a/tests/qemu-iotests/051 b/tests/qemu-iotests/051
index 2465e48..f8141ca 100755
--- a/tests/qemu-iotests/051
+++ b/tests/qemu-iotests/051
@@ -251,11 +251,11 @@  echo
 # Cannot use the test image because cache=none might not work on the host FS
 # Use cdrom so that we won't get errors about missing media
 
-run_qemu -drive driver=null-co,cache=none
-run_qemu -drive driver=null-co,cache=directsync
-run_qemu -drive driver=null-co,cache=writeback
-run_qemu -drive driver=null-co,cache=writethrough
-run_qemu -drive driver=null-co,cache=unsafe
+run_qemu -drive driver=null-co,read-zeroes=on,cache=none
+run_qemu -drive driver=null-co,read-zeroes=on,cache=directsync
+run_qemu -drive driver=null-co,read-zeroes=on,cache=writeback
+run_qemu -drive driver=null-co,read-zeroes=on,cache=writethrough
+run_qemu -drive driver=null-co,read-zeroes=on,cache=unsafe
 run_qemu -drive driver=null-co,cache=invalid_value
 
 # Can't test direct=on here because O_DIRECT might not be supported on this FS
diff --git a/tests/qemu-iotests/051.pc.out b/tests/qemu-iotests/051.pc.out
index 2d811c1..000557c 100644
--- a/tests/qemu-iotests/051.pc.out
+++ b/tests/qemu-iotests/051.pc.out
@@ -245,23 +245,23 @@  QEMU X.Y.Z monitor - type 'help' for more information
 
 === Cache modes ===
 
-Testing: -drive driver=null-co,cache=none
+Testing: -drive driver=null-co,read-zeroes=on,cache=none
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) quit
 
-Testing: -drive driver=null-co,cache=directsync
+Testing: -drive driver=null-co,read-zeroes=on,cache=directsync
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) quit
 
-Testing: -drive driver=null-co,cache=writeback
+Testing: -drive driver=null-co,read-zeroes=on,cache=writeback
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) quit
 
-Testing: -drive driver=null-co,cache=writethrough
+Testing: -drive driver=null-co,read-zeroes=on,cache=writethrough
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) quit
 
-Testing: -drive driver=null-co,cache=unsafe
+Testing: -drive driver=null-co,read-zeroes=on,cache=unsafe
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) quit
 
diff --git a/tests/qemu-iotests/186 b/tests/qemu-iotests/186
index 7e7d45b..5f6b18c 100755
--- a/tests/qemu-iotests/186
+++ b/tests/qemu-iotests/186
@@ -86,8 +86,8 @@  echo "=== -blockdev/-device=<node-name> ==="
 echo
 
 for dev in $fixed $removable; do
-    check_info_block -blockdev driver=null-co,node-name=null -device $dev,drive=null
-    check_info_block -blockdev driver=null-co,node-name=null -device $dev,drive=null,id=qdev_id
+    check_info_block -blockdev driver=null-co,read-zeroes=on,node-name=null -device $dev,drive=null
+    check_info_block -blockdev driver=null-co,read-zeroes=on,node-name=null -device $dev,drive=null,id=qdev_id
 done
 
 echo
@@ -97,7 +97,7 @@  echo
 # This creates two BlockBackends that will show up in 'info block'!
 # A monitor-owned one from -drive, and anonymous one from -device
 for dev in $fixed $removable; do
-    check_info_block -drive if=none,driver=null-co,node-name=null -device $dev,drive=null,id=qdev_id
+    check_info_block -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device $dev,drive=null,id=qdev_id
 done
 
 echo
@@ -105,8 +105,8 @@  echo "=== -drive if=none/-device=<bb-name> (with medium) ==="
 echo
 
 for dev in $fixed $removable; do
-    check_info_block -drive if=none,driver=null-co,node-name=null -device $dev,drive=none0
-    check_info_block -drive if=none,driver=null-co,node-name=null -device $dev,drive=none0,id=qdev_id
+    check_info_block -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device $dev,drive=none0
+    check_info_block -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device $dev,drive=none0,id=qdev_id
 done
 
 echo
@@ -125,15 +125,15 @@  echo "=== -drive if=... ==="
 echo
 
 check_info_block -drive if=floppy
-check_info_block -drive if=floppy,driver=null-co
+check_info_block -drive if=floppy,driver=null-co,read-zeroes=on
 
-check_info_block -drive if=ide,driver=null-co
+check_info_block -drive if=ide,driver=null-co,read-zeroes=on
 check_info_block -drive if=ide,media=cdrom
-check_info_block -drive if=ide,driver=null-co,media=cdrom
+check_info_block -drive if=ide,driver=null-co,read-zeroes=on,media=cdrom
 
-check_info_block -drive if=virtio,driver=null-co
+check_info_block -drive if=virtio,driver=null-co,read-zeroes=on
 
-check_info_block -drive if=pflash,driver=null-co,size=1M
+check_info_block -drive if=pflash,driver=null-co,read-zeroes=on,size=1M
 
 # success, all done
 echo "*** done"
diff --git a/tests/qemu-iotests/186.out b/tests/qemu-iotests/186.out
index 716b01a..5b35040 100644
--- a/tests/qemu-iotests/186.out
+++ b/tests/qemu-iotests/186.out
@@ -54,103 +54,103 @@  qdev_id: [not inserted]
 
 === -blockdev/-device=<node-name> ===
 
-Testing: -blockdev driver=null-co,node-name=null -device ide-hd,drive=null
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device ide-hd,drive=null
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device ide-hd,drive=null,id=qdev_id
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device ide-hd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device scsi-hd,drive=null
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device scsi-hd,drive=null
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device scsi-hd,drive=null,id=qdev_id
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device scsi-hd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device virtio-blk-pci,drive=null
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device virtio-blk-pci,drive=null
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device virtio-blk-pci,drive=null,id=qdev_id
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device virtio-blk-pci,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device floppy,drive=null
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device floppy,drive=null
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device floppy,drive=null,id=qdev_id
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device floppy,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device ide-cd,drive=null
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device ide-cd,drive=null
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device ide-cd,drive=null,id=qdev_id
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device ide-cd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device scsi-cd,drive=null
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device scsi-cd,drive=null
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -blockdev driver=null-co,node-name=null -device scsi-cd,drive=null,id=qdev_id
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device scsi-cd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-null: null-co:// (null-co)
+null: json:{"read-zeroes": true, "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
@@ -159,76 +159,76 @@  null: null-co:// (null-co)
 
 === -drive if=none/-device=<node-name> ===
 
-Testing: -drive if=none,driver=null-co,node-name=null -device ide-hd,drive=null,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device ide-hd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Removable device: not locked, tray closed
     Cache mode:       writeback
 
-null: null-co:// (null-co)
+null: json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device scsi-hd,drive=null,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device scsi-hd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Removable device: not locked, tray closed
     Cache mode:       writeback
 
-null: null-co:// (null-co)
+null: json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device virtio-blk-pci,drive=null,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device virtio-blk-pci,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Removable device: not locked, tray closed
     Cache mode:       writeback
 
-null: null-co:// (null-co)
+null: json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device floppy,drive=null,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device floppy,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Removable device: not locked, tray closed
     Cache mode:       writeback
 
-null: null-co:// (null-co)
+null: json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device ide-cd,drive=null,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device ide-cd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Removable device: not locked, tray closed
     Cache mode:       writeback
 
-null: null-co:// (null-co)
+null: json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device scsi-cd,drive=null,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device scsi-cd,drive=null,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Removable device: not locked, tray closed
     Cache mode:       writeback
 
-null: null-co:// (null-co)
+null: json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
@@ -237,103 +237,103 @@  null: null-co:// (null-co)
 
 === -drive if=none/-device=<bb-name> (with medium) ===
 
-Testing: -drive if=none,driver=null-co,node-name=null -device ide-hd,drive=none0
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device ide-hd,drive=none0
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device ide-hd,drive=none0,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device ide-hd,drive=none0,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device scsi-hd,drive=none0
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device scsi-hd,drive=none0
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device scsi-hd,drive=none0,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device scsi-hd,drive=none0,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device virtio-blk-pci,drive=none0
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device virtio-blk-pci,drive=none0
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device virtio-blk-pci,drive=none0,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device virtio-blk-pci,drive=none0,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device floppy,drive=none0
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device floppy,drive=none0
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device floppy,drive=none0,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device floppy,drive=none0,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device ide-cd,drive=none0
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device ide-cd,drive=none0
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device ide-cd,drive=none0,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device ide-cd,drive=none0,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device scsi-cd,drive=none0
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device scsi-cd,drive=none0
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=none,driver=null-co,node-name=null -device scsi-cd,drive=none0,id=qdev_id
+Testing: -drive if=none,driver=null-co,read-zeroes=on,node-name=null -device scsi-cd,drive=none0,id=qdev_id
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-none0 (null): null-co:// (null-co)
+none0 (null): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      qdev_id
     Removable device: not locked, tray closed
     Cache mode:       writeback
@@ -408,19 +408,19 @@  floppy0: [not inserted]
     Removable device: not locked, tray closed
 (qemu) quit
 
-Testing: -drive if=floppy,driver=null-co
+Testing: -drive if=floppy,driver=null-co,read-zeroes=on
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-floppy0 (NODE_NAME): null-co:// (null-co)
+floppy0 (NODE_NAME): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=ide,driver=null-co
+Testing: -drive if=ide,driver=null-co,read-zeroes=on
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-ide0-hd0 (NODE_NAME): null-co:// (null-co)
+ide0-hd0 (NODE_NAME): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
@@ -433,27 +433,27 @@  ide0-cd0: [not inserted]
     Removable device: not locked, tray closed
 (qemu) quit
 
-Testing: -drive if=ide,driver=null-co,media=cdrom
+Testing: -drive if=ide,driver=null-co,read-zeroes=on,media=cdrom
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-ide0-cd0 (NODE_NAME): null-co:// (null-co, read-only)
+ide0-cd0 (NODE_NAME): json:{"read-zeroes": "on", "driver": "null-co"} (null-co, read-only)
     Attached to:      PATH
     Removable device: not locked, tray closed
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=virtio,driver=null-co
+Testing: -drive if=virtio,driver=null-co,read-zeroes=on
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-virtio0 (NODE_NAME): null-co:// (null-co)
+virtio0 (NODE_NAME): json:{"read-zeroes": "on", "driver": "null-co"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
 
-Testing: -drive if=pflash,driver=null-co,size=1M
+Testing: -drive if=pflash,driver=null-co,read-zeroes=on,size=1M
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) info block
-pflash0 (NODE_NAME): json:{"driver": "null-co", "size": "1M"} (null-co)
+pflash0 (NODE_NAME): json:{"read-zeroes": "on", "driver": "null-co", "size": "1M"} (null-co)
     Attached to:      PATH
     Cache mode:       writeback
 (qemu) quit
diff --git a/tests/qemu-iotests/227 b/tests/qemu-iotests/227
index bdd727a..637d7c3 100755
--- a/tests/qemu-iotests/227
+++ b/tests/qemu-iotests/227
@@ -57,7 +57,7 @@  echo
 echo '=== blockstats with -drive if=virtio ==='
 echo
 
-run_qemu -drive driver=null-co,if=virtio <<EOF
+run_qemu -drive driver=null-co,read-zeroes=on,if=virtio <<EOF
 { "execute": "qmp_capabilities" }
 { "execute": "query-blockstats"}
 { "execute": "quit" }
@@ -87,7 +87,7 @@  echo
 echo '=== blockstats with -blockdev and -device ==='
 echo
 
-run_qemu -blockdev driver=null-co,node-name=null -device virtio-blk,drive=null,id=virtio0 <<EOF
+run_qemu -blockdev driver=null-co,read-zeroes=on,node-name=null -device virtio-blk,drive=null,id=virtio0 <<EOF
 { "execute": "qmp_capabilities" }
 { "execute": "query-blockstats"}
 { "execute": "quit" }
diff --git a/tests/qemu-iotests/227.out b/tests/qemu-iotests/227.out
index e77efaf..3dd3ca5 100644
--- a/tests/qemu-iotests/227.out
+++ b/tests/qemu-iotests/227.out
@@ -2,7 +2,7 @@  QA output created by 227
 
 === blockstats with -drive if=virtio ===
 
-Testing: -drive driver=null-co,if=virtio
+Testing: -drive driver=null-co,read-zeroes=on,if=virtio
 {
     QMP_VERSION
 }
@@ -150,7 +150,7 @@  Testing: -blockdev driver=null-co,node-name=null
 
 === blockstats with -blockdev and -device ===
 
-Testing: -blockdev driver=null-co,node-name=null -device virtio-blk,drive=null,id=virtio0
+Testing: -blockdev driver=null-co,read-zeroes=on,node-name=null -device virtio-blk,drive=null,id=virtio0
 {
     QMP_VERSION
 }
diff --git a/tests/qemu-iotests/240 b/tests/qemu-iotests/240
index 5be6b9c..f73bc07 100755
--- a/tests/qemu-iotests/240
+++ b/tests/qemu-iotests/240
@@ -76,7 +76,7 @@  echo
 
 run_qemu <<EOF
 { "execute": "qmp_capabilities" }
-{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "hd0"}}
+{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "read-zeroes": true, "node-name": "hd0"}}
 { "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread0"}}
 { "execute": "device_add", "arguments": {"id": "scsi0", "driver": "${virtio_scsi}", "iothread": "iothread0"}}
 { "execute": "device_add", "arguments": {"id": "scsi-hd0", "driver": "scsi-hd", "drive": "hd0"}}
@@ -94,7 +94,7 @@  echo
 
 run_qemu <<EOF
 { "execute": "qmp_capabilities" }
-{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "hd0", "read-only": true}}
+{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "read-zeroes": true, "node-name": "hd0", "read-only": true}}
 { "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread0"}}
 { "execute": "device_add", "arguments": {"id": "scsi0", "driver": "${virtio_scsi}", "iothread": "iothread0"}}
 { "execute": "device_add", "arguments": {"id": "scsi-hd0", "driver": "scsi-hd", "drive": "hd0"}}
@@ -112,7 +112,7 @@  echo
 
 run_qemu <<EOF
 { "execute": "qmp_capabilities" }
-{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "hd0", "read-only": true}}
+{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "read-zeroes": true, "node-name": "hd0", "read-only": true}}
 { "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread0"}}
 { "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread1"}}
 { "execute": "device_add", "arguments": {"id": "scsi0", "driver": "${virtio_scsi}", "iothread": "iothread0"}}
@@ -134,7 +134,7 @@  echo
 
 run_qemu <<EOF
 { "execute": "qmp_capabilities" }
-{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "hd0", "read-only": true}}
+{ "execute": "blockdev-add", "arguments": {"driver": "null-co", "read-zeroes": true, "node-name": "hd0", "read-only": true}}
 { "execute": "nbd-server-start", "arguments": {"addr":{"type":"unix","data":{"path":"$TEST_DIR/nbd"}}}}
 { "execute": "nbd-server-add", "arguments": {"device":"hd0"}}
 { "execute": "object-add", "arguments": {"qom-type": "iothread", "id": "iothread0"}}