[PATCH 2/3] hmp: Allow using qdev ID for qemu-io command

[Kevin Wolf <kwolf@redhat.com>]

In order to issue requests on an existing BlockBackend with the
'qemu-io' HMP command, allow specifying the BlockBackend not only with a
BlockBackend name, but also with a qdev ID/QOM path for a device that
owns the (possibly anonymous) BlockBackend.

Because qdev names could be conflicting with BlockBackend and node
names, introduce a -d option to explicitly address a device. If the
option is not given, a BlockBackend or a node is addressed.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 monitor/hmp-cmds.c | 28 ++++++++++++++++++----------
 hmp-commands.hx    |  8 +++++---
 2 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index b2551c16d1..5f8941d298 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -2468,23 +2468,31 @@ void hmp_qemu_io(Monitor *mon, const QDict *qdict)
 {
     BlockBackend *blk;
     BlockBackend *local_blk = NULL;
+    bool qdev = qdict_get_try_bool(qdict, "qdev", false);
     const char* device = qdict_get_str(qdict, "device");
     const char* command = qdict_get_str(qdict, "command");
     Error *err = NULL;
     int ret;
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        BlockDriverState *bs = bdrv_lookup_bs(NULL, device, &err);
-        if (bs) {
-            blk = local_blk = blk_new(bdrv_get_aio_context(bs),
-                                      0, BLK_PERM_ALL);
-            ret = blk_insert_bs(blk, bs, &err);
-            if (ret < 0) {
+    if (qdev) {
+        blk = blk_by_qdev_id(device, &err);
+        if (!blk) {
+            goto fail;
+        }
+    } else {
+        blk = blk_by_name(device);
+        if (!blk) {
+            BlockDriverState *bs = bdrv_lookup_bs(NULL, device, &err);
+            if (bs) {
+                blk = local_blk = blk_new(bdrv_get_aio_context(bs),
+                                          0, BLK_PERM_ALL);
+                ret = blk_insert_bs(blk, bs, &err);
+                if (ret < 0) {
+                    goto fail;
+                }
+            } else {
                 goto fail;
             }
-        } else {
-            goto fail;
         }
     }
 
diff --git a/hmp-commands.hx b/hmp-commands.hx
index cfcc044ce4..dc23185de4 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1875,9 +1875,11 @@ ETEXI
 
     {
         .name       = "qemu-io",
-        .args_type  = "device:B,command:s",
-        .params     = "[device] \"[command]\"",
-        .help       = "run a qemu-io command on a block device",
+        .args_type  = "qdev:-d,device:B,command:s",
+        .params     = "[-d] [device] \"[command]\"",
+        .help       = "run a qemu-io command on a block device\n\t\t\t"
+                      "-d: [device] is a device ID rather than a "
+                      "drive ID or node name",
         .cmd        = hmp_qemu_io,
     },
 
-- 
2.20.1