block: add x-qemu-io QMP command

Add an x-qemu-io QMP command that runs qemu-io commands on block
devices. The command accepts a device name (block backend name,
node-name, or qdev ID) and a qemu-io command string.

Refactor hmp_qemu_io() to be a thin wrapper around the new QMP
command, following the standard HMP-over-QMP pattern used by other
block commands.

This change is also required for the qtest qemu-io command in the
following patch.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20260828-qemu-no-hmp-v5-22-9227de146347@redhat.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/qapi/block.json b/qapi/block.json
index 46955bbb3e..012a9d7333 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -603,3 +603,37 @@
            '*boundaries-zap': ['uint64'],
            '*boundaries-flush': ['uint64'] },
   'allow-preconfig': true }
+
+##
+# @x-qemu-io:
+#
+# Run a qemu-io command on a block device.  Take either a block
+# backend name or a qdev ID to identify the device.
+#
+# @device: the block backend name, node-name to run the
+#     command on.
+#
+# @qdev: the qdev ID of the block device to run the
+#     command on.
+#
+# @command: the qemu-io command string to execute.
+#
+# Features:
+#
+# @unstable: This command is for testing only.
+#
+# Since: 11.2
+#
+# .. qmp-example::
+#
+#     -> { "execute": "x-qemu-io",
+#          "arguments": { "device": "virtio0",
+#                         "command": "read 0 512" } }
+#     <- { "return": {} }
+##
+{ 'command': 'x-qemu-io',
+  'data': { '*device': 'str',
+            '*qdev': 'str',
+            'command': 'str' },
+  'features': [ 'unstable' ],
+  'allow-preconfig': true }