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Revision 6d4cd408

ID6d4cd408686f5ae60b2b3b94b79f48ddedc2f39d

Added by Markus Armbruster almost 11 years ago

qemu-option: Fix qemu_opts_set_defaults() for corner cases

Commit 4f6dd9a changed the initialization of opts in opts_parse() to
this:

if (defaults) {
if (!id && !QTAILQ_EMPTY(&list->head)) {
opts = qemu_opts_find(list, NULL);
} else {
opts = qemu_opts_create(list, id, 0);
}
} else {
opts = qemu_opts_create(list, id, 1);
}

Same as before for !defaults.

If defaults is true, and params has no ID, and options exist, we use
the first assignment. It sets opts to null if all options have an ID.
opts_parse() then returns null. qemu_opts_set_defaults() asserts the
value is non-null. It's the only caller that passes true for
defaults.

To reproduce, try "-M xenpv -machine id=foo" (yes, "id=foo" is silly,
but it shouldn't crash).

I believe the function attempts to do the following:

If options don't yet exist, create new options
Else, if defaults, modify the existing options
Else, if list->merge_lists, modify the existing options
Else, fail

A straightforward call of qemu_opts_create() does exactly that.

Cc: Jan Kiszka <>
Signed-off-by: Markus Armbruster <>
Message-id:
Signed-off-by: Anthony Liguori <>

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