[PATCH for-12] qed: deprecate the block driver

[PATCH for-12] qed: deprecate the block driver

[Stefan Hajnoczi]

It has been unofficially deprecated on the wiki for many years:
https://wiki.qemu.org/Features/QED

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 docs/about/deprecated.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 0891bbc44de..ab83626af0b 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -526,3 +526,16 @@ If the user requests a modern x86 CPU model (i.e. not one of ``486``,
 ``athlon``, ``kvm32``, ``pentium``, ``pentium2``, ``pentium3``or ``qemu32``)
 a warning will be displayed until a future QEMU version when such CPUs will
 be rejected.
+
+Block drivers
+-------------
+
+QED (since 12.0)
+''''''''''''''''
+
+The QED disk image format is not actively maintained and qcow2 has exceeded its
+features and performance for many years. Since QED was never widely deployed,
+the format is not required for compatibility reasons. It is unlikely that
+qemu-img users still need to convert images to or from QED.
+
+Use qcow2 instead of QED.
-- 
2.56.0

Re: [PATCH for-12] qed: deprecate the block driver

[Daniel P. Berrangé]

On Mon, Nov 09, 2026 at 09:34:31AM -0700, Stefan Hajnoczi wrote:
> It has been unofficially deprecated on the wiki for many years:
> https://wiki.qemu.org/Features/QED
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  docs/about/deprecated.rst | 13 +++++++++++++
>  1 file changed, 13 insertions(+)

How about bdrv_qed_open also adding

  warn_report_once("QED is deprecated, please switch to qcow2");

for the part of the user population who never reads the docs.

> 
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index 0891bbc44de..ab83626af0b 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -526,3 +526,16 @@ If the user requests a modern x86 CPU model (i.e. not one of ``486``,
>  ``athlon``, ``kvm32``, ``pentium``, ``pentium2``, ``pentium3``or ``qemu32``)
>  a warning will be displayed until a future QEMU version when such CPUs will
>  be rejected.
> +
> +Block drivers
> +-------------
> +
> +QED (since 12.0)
> +''''''''''''''''
> +
> +The QED disk image format is not actively maintained and qcow2 has exceeded its
> +features and performance for many years. Since QED was never widely deployed,
> +the format is not required for compatibility reasons. It is unlikely that
> +qemu-img users still need to convert images to or from QED.
> +
> +Use qcow2 instead of QED.
> -- 
> 2.56.0
> 

With regards,
Daniel
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