From ede6c50c5236dd0cdbcef242320ad3c8bc2bbfd3 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Tue, 3 Apr 2012 14:04:31 +0200
Subject: [PATCH] usb-ehci: Ensure frindex writes leave a valid frindex value

frindex is a 14 bits counter, so bits 31-14 should always be 0, and
after the commit titled "usb-ehci: frindex always is a 14 bits counter"
we rely on frindex always being a multiple of 8. I've not seen this in
practice, but theoretically a guest can write a value >= 0x4000 or a value
which is not a multiple of 8 value to frindex, this patch ensures that
things will still work when that happens.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 hw/usb-ehci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/usb-ehci.c b/hw/usb-ehci.c
index ff69587..16e6053 100644
--- a/hw/usb-ehci.c
+++ b/hw/usb-ehci.c
@@ -1081,6 +1081,10 @@ static void ehci_mem_writel(void *ptr, target_phys_addr_t addr, uint32_t val)
         val &= USBINTR_MASK;
         break;
 
+    case FRINDEX:
+        val &= 0x00003ff8; /* frindex is 14bits and always a multiple of 8 */
+        break;
+
     case CONFIGFLAG:
         val &= 0x1;
         if (val) {