From c3604429d4e4dfb00bc536962dbe3154c938b571 Mon Sep 17 00:00:00 2001
From: Daniel Samson <12231216+daniel-samson@users.noreply.github.com>
Date: Sun, 9 Aug 2026 14:09:19 +0100
Subject: [PATCH] =?UTF-8?q?test:=20H3=20=E2=80=94=20a=20nested=20hub=20tre?=
 =?UTF-8?q?e=20yanked=20whole=20rebuilds=20whole=20(hot-plug=20matrix)?=
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hub -> hub -> keyboard, one device_del of the outer hub: the H2 recursion
runs at depth two (the inner hub is torn down as a child, its keyboard
first), the keyboard's driver is reaped, and re-adding all three rebinds.
---
 test/qemu_test.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/test/qemu_test.py b/test/qemu_test.py
index d66334d..3af4112 100644
--- a/test/qemu_test.py
+++ b/test/qemu_test.py
@@ -1037,6 +1037,30 @@ CASES = [
                r"(?=.*device-manager: reaping \S*usb-hid-keyboard[\s\S]*usb-hid-keyboard: ok)"
                r"(?=.*device-manager: reaping \S*usb-hid-mouse[\s\S]*usb-hid-mouse: ok)",
      "fail":   r"DANOS-TEST-RESULT: FAIL"},
+    # Hot-plug matrix H3 (docs/hot-plug-matrix-plan.md): yank a NESTED hub tree.
+    # hub → hub → keyboard, one device_del of the outer hub — the recursion must
+    # go two levels (inner hub torn down as a child, ITS keyboard first), the
+    # keyboard's driver reaped, and re-adding all three rebuilds and rebinds.
+    {"name": "usb-hub-nested-yank",
+     "build_case": "usb-hid",
+     "smp":    4,
+     "timeout": 150,
+     "qemu_extra": ["-device", "qemu-xhci,id=xhci2",
+                    "-device", "usb-hub,bus=xhci2.0,port=1,id=ohub",
+                    "-device", "usb-hub,bus=xhci2.0,port=1.1,id=ihub",
+                    "-device", "usb-kbd,bus=xhci2.0,port=1.1.1,id=nkbd"],
+     "qmp_sequence": [
+         {"delay": 8,  "command": "device_del", "arguments": {"id": "ohub"}},
+         {"delay": 14, "command": "device_add",
+          "arguments": {"driver": "usb-hub", "bus": "xhci2.0", "port": "1", "id": "ohub2"}},
+         {"delay": 17, "command": "device_add",
+          "arguments": {"driver": "usb-hub", "bus": "xhci2.0", "port": "1.1", "id": "ihub2"}},
+         {"delay": 20, "command": "device_add",
+          "arguments": {"driver": "usb-kbd", "bus": "xhci2.0", "port": "1.1.1", "id": "nkbd2"}},
+     ],
+     "expect": r"(?s)(?=.*hub device slot \d+ disconnected)"
+               r"(?=.*device-manager: reaping \S*usb-hid-keyboard[\s\S]*usb-hid-keyboard: ok)",
+     "fail":   r"DANOS-TEST-RESULT: FAIL"},
     # The kernel VFS root (M-F): the mount table serves the initrd at /system —
     # path resolution, node status/read (an ELF magic), and directory listing,
     # asserted kernel-side.