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 <hdego...@redhat.com> --- hw/usb/hcd-ehci.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c index 64b58e3..8865b4e 100644 --- a/hw/usb/hcd-ehci.c +++ b/hw/usb/hcd-ehci.c @@ -1102,6 +1102,10 @@ 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) { -- 1.7.9.3