From fc30920731470a44c69c8359be45b72ac7314fb6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Wed, 8 Sep 2021 10:35:43 +0100
Subject: [PATCH] qapi: introduce x-query-usb QMP command
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This is a counterpart to the HMP "info usb" command. It is being
added with an "x-" prefix because this QMP command is intended as an
adhoc debugging tool and will thus not be modelled in QAPI as fully
structured data, nor will it have long term guaranteed stability.
The existing HMP command is rewritten to call the QMP command.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 hmp-commands-info.hx       |  2 +-
 hw/usb/bus.c               | 24 +++++++++++++++---------
 qapi/machine.json          | 12 ++++++++++++
 stubs/usb-dev-stub.c       |  8 ++++++++
 tests/qtest/qmp-cmd-test.c |  2 ++
 5 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index f66b1ca986..ef1bfe4f5a 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -338,7 +338,7 @@ ERST
         .args_type  = "",
         .params     = "",
         .help       = "show guest USB devices",
-        .cmd        = hmp_info_usb,
+        .cmd_info_hrt = qmp_x_query_usb,
     },
 
 SRST
diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index 5d441a7065..92d6ed5626 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -2,6 +2,8 @@
 #include "hw/qdev-properties.h"
 #include "hw/usb.h"
 #include "qapi/error.h"
+#include "qapi/qapi-commands-machine.h"
+#include "qapi/type-helpers.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "sysemu/sysemu.h"
@@ -631,15 +633,16 @@ static char *usb_get_fw_dev_path(DeviceState *qdev)
     return fw_path;
 }
 
-void hmp_info_usb(Monitor *mon, const QDict *qdict)
+HumanReadableText *qmp_x_query_usb(Error **errp)
 {
+    g_autoptr(GString) buf = g_string_new("");
     USBBus *bus;
     USBDevice *dev;
     USBPort *port;
 
     if (QTAILQ_EMPTY(&busses)) {
-        monitor_printf(mon, "USB support not enabled\n");
-        return;
+        error_setg(errp, "USB support not enabled");
+        return NULL;
     }
 
     QTAILQ_FOREACH(bus, &busses, next) {
@@ -647,14 +650,17 @@ void hmp_info_usb(Monitor *mon, const QDict *qdict)
             dev = port->dev;
             if (!dev)
                 continue;
-            monitor_printf(mon, "  Device %d.%d, Port %s, Speed %s Mb/s, "
-                           "Product %s%s%s\n",
-                           bus->busnr, dev->addr, port->path,
-                           usb_speed(dev->speed), dev->product_desc,
-                           dev->qdev.id ? ", ID: " : "",
-                           dev->qdev.id ?: "");
+            g_string_append_printf(buf,
+                                   "  Device %d.%d, Port %s, Speed %s Mb/s, "
+                                   "Product %s%s%s\n",
+                                   bus->busnr, dev->addr, port->path,
+                                   usb_speed(dev->speed), dev->product_desc,
+                                   dev->qdev.id ? ", ID: " : "",
+                                   dev->qdev.id ?: "");
         }
     }
+
+    return human_readable_text_from_str(buf);
 }
 
 /* handle legacy -usbdevice cmd line option */
diff --git a/qapi/machine.json b/qapi/machine.json
index 3732f80a82..15b6c98597 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -1447,3 +1447,15 @@
 ##
 { 'command': 'x-query-roms',
   'returns': 'HumanReadableText' }
+
+##
+# @x-query-usb:
+#
+# Query information on the USB devices
+#
+# Returns: USB device information
+#
+# Since: 6.2
+##
+{ 'command': 'x-query-usb',
+  'returns': 'HumanReadableText' }
diff --git a/stubs/usb-dev-stub.c b/stubs/usb-dev-stub.c
index b1adeeb454..aa557692b7 100644
--- a/stubs/usb-dev-stub.c
+++ b/stubs/usb-dev-stub.c
@@ -8,6 +8,8 @@
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-machine.h"
 #include "sysemu/sysemu.h"
 #include "monitor/monitor.h"
 #include "hw/usb.h"
@@ -19,6 +21,12 @@ USBDevice *usbdevice_create(const char *driver)
     return NULL;
 }
 
+HumanReadableText *qmp_x_query_usb(Error **errp)
+{
+    error_setg(errp, "Support for USB devices not built-in");
+    return NULL;
+}
+
 void hmp_info_usb(Monitor *mon, const QDict *qdict)
 {
     monitor_printf(mon, "Support for USB devices not built-in\n");
diff --git a/tests/qtest/qmp-cmd-test.c b/tests/qtest/qmp-cmd-test.c
index 372c887eea..0d52ea6c4b 100644
--- a/tests/qtest/qmp-cmd-test.c
+++ b/tests/qtest/qmp-cmd-test.c
@@ -49,6 +49,8 @@ static int query_error_class(const char *cmd)
 #ifndef CONFIG_PROFILER
         { "x-query-profile", ERROR_CLASS_GENERIC_ERROR },
 #endif
+        /* Only valid with a USB bus added */
+        { "x-query-usb", ERROR_CLASS_GENERIC_ERROR },
         { NULL, -1 }
     };
     int i;