From c41159084d8e82fec018e1ff469e88c882eeacdb Mon Sep 17 00:00:00 2001
From: Martin Whitaker <memtest@martin-whitaker.me.uk>
Date: Fri, 9 Sep 2022 19:48:59 +0100
Subject: [PATCH] Guard against unsupported or invalid USB controller types.

---
 system/usbhcd.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/system/usbhcd.c b/system/usbhcd.c
index 6f218cc..e77ae21 100644
--- a/system/usbhcd.c
+++ b/system/usbhcd.c
@@ -751,6 +751,10 @@ void find_usb_keyboards(bool pause_if_none)
                     uint16_t class_code = pci_config_read16(bus, dev, func, 0x0a);
                     if (class_code == 0x0c03) {
                         controller_type[func] = pci_config_read8(bus, dev, func, 0x09) >> 4;
+                        if (controller_type[func] >= MAX_HCI_TYPE) {
+                            // Unsupported or invalid controller type - ignore it.
+                            controller_type[func] = NOT_HCI;
+                        }
                         // We need to initialise EHCI controllers before initialising any of their companion
                         // controllers, so do it now.
                         if (controller_type[func] == EHCI) {