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Diffstat (limited to 'docs/system/deprecated.rst')
| -rw-r--r-- | docs/system/deprecated.rst | 32 |
1 files changed, 0 insertions, 32 deletions
diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst index 94fb7dbf4e..6d438f1c8d 100644 --- a/docs/system/deprecated.rst +++ b/docs/system/deprecated.rst @@ -300,38 +300,6 @@ this CPU is also deprecated. Related binaries ---------------- -qemu-img amend to adjust backing file (since 5.1) -''''''''''''''''''''''''''''''''''''''''''''''''' - -The use of ``qemu-img amend`` to modify the name or format of a qcow2 -backing image is deprecated; this functionality was never fully -documented or tested, and interferes with other amend operations that -need access to the original backing image (such as deciding whether a -v3 zero cluster may be left unallocated when converting to a v2 -image). Rather, any changes to the backing chain should be performed -with ``qemu-img rebase -u`` either before or after the remaining -changes being performed by amend, as appropriate. - -qemu-img backing file without format (since 5.1) -'''''''''''''''''''''''''''''''''''''''''''''''' - -The use of ``qemu-img create``, ``qemu-img rebase``, or ``qemu-img -convert`` to create or modify an image that depends on a backing file -now recommends that an explicit backing format be provided. This is -for safety: if QEMU probes a different format than what you thought, -the data presented to the guest will be corrupt; similarly, presenting -a raw image to a guest allows a potential security exploit if a future -probe sees a non-raw image based on guest writes. - -To avoid the warning message, or even future refusal to create an -unsafe image, you must pass ``-o backing_fmt=`` (or the shorthand -``-F`` during create) to specify the intended backing format. You may -use ``qemu-img rebase -u`` to retroactively add a backing format to an -existing image. However, be aware that there are already potential -security risks to blindly using ``qemu-img info`` to probe the format -of an untrusted backing image, when deciding what format to add into -an existing image. - Backwards compatibility ----------------------- |