功能：接入Linux原生光标并完善设备接入工具

tools/usb-device-qmp.py

@@ -116,13 +116,41 @@ def ensure(qmp, vm, port, bus, vendor=None, product=None):
         attach(qmp, vm, port, bus, vendor, product)
 
 
-def watch(vm, port, bus, vendor=None, product=None, interval=3):
-    """Keep the runtime endpoint attached across VM restarts."""
+def probe_status(port, host="127.0.0.1", timeout=0.7):
+    """Return whether the box has an exportable storage device ready."""
+    try:
+        with socket.create_connection((host, port), timeout=timeout) as stream:
+            stream.settimeout(timeout)
+            return stream.recv(32).strip() == b"ready"
+    except OSError:
+        return False
+
+
+def watch(vm, port, bus, vendor=None, product=None, interval=3,
+          status_port=None, remove_after=3):
+    """Track the box device and keep the guest endpoint in sync.
+
+    With status_port, the QEMU endpoint is present only while the box reports
+    an exportable physical storage device.  A short missing-device debounce
+    prevents a transient udev/export restart from causing a guest hot-unplug.
+    Without status_port this retains the legacy always-present behavior.
+    """
+    missing = 0
     while True:
         try:
+            ready = True if status_port is None else probe_status(status_port)
             qmp = Qmp(vm)
             try:
-                ensure(qmp, vm, port, bus, vendor, product)
+                channel, device = ids(vm)
+                present = device in peripherals(qmp)
+                if ready:
+                    missing = 0
+                    if not present:
+                        attach(qmp, vm, port, bus, vendor, product)
+                else:
+                    missing += 1
+                    if present and missing >= remove_after:
+                        detach(qmp, vm)
             finally:
                 qmp.close()
         except (OSError, RuntimeError) as exc:
@@ -140,11 +168,21 @@ def main():
     parser.add_argument("--product")
     parser.add_argument("--any-storage", action="store_true",
                         help="Allow any pure USB Mass Storage device")
+    parser.add_argument("--status-port", type=int,
+                        help="loopback port forwarded to the box readiness endpoint")
+    parser.add_argument("--interval", type=float, default=3,
+                        help="watch polling interval in seconds")
+    parser.add_argument("--remove-after", type=int, default=3,
+                        help="consecutive empty probes before guest removal")
     parser.add_argument("--guest-ejected", action="store_true",
                         help="Confirm the guest has safely ejected the USB device before detach")
     args = parser.parse_args()
     if args.vm < 100 or not 1 <= args.port <= 65535:
         parser.error("invalid VM ID or local tunnel port")
+    if args.status_port is not None and not 1 <= args.status_port <= 65535:
+        parser.error("invalid status port")
+    if args.interval <= 0 or args.remove_after < 1:
+        parser.error("interval must be positive and remove-after must be at least one")
     if args.action in ("attach", "watch"):
         exact = all(re.fullmatch(r"[0-9a-fA-F]{4}", x or "") for x in [args.vendor, args.product])
         if args.any_storage and (args.vendor or args.product):
@@ -156,7 +194,9 @@ def main():
     if args.action == "watch":
         watch(args.vm, args.port, args.bus,
               None if args.any_storage else args.vendor.lower(),
-              None if args.any_storage else args.product.lower())
+              None if args.any_storage else args.product.lower(),
+              interval=args.interval, status_port=args.status_port,
+              remove_after=args.remove_after)
         return
     if args.action == "detach" and not args.guest_ejected:
         parser.error("safely eject in the guest first, then pass --guest-ejected")