From 1cbdde909f70fd15ff85f068a6318b73865c7fa3 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sat, 17 Nov 2012 12:11:50 +0100 Subject: uhci: Don't allow the guest to set port-enabled when there is no dev connected It is possible for device disconnect and the guest trying to reset the port (because of USB xact errors prior to the disconnect getting signaled) to race, when we hit this race, the guest will write the port-control register with its pre-disconnect value + the reset bit set, after which we have a disconnected device with its port-enabled bit set in its port-control register, which is no good :) Signed-off-by: Hans de Goede Signed-off-by: Gerd Hoffmann --- hw/usb/hcd-uhci.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'hw/usb/hcd-uhci.c') diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c index ef326330d3..078be2ad6a 100644 --- a/hw/usb/hcd-uhci.c +++ b/hw/usb/hcd-uhci.c @@ -556,6 +556,10 @@ static void uhci_ioport_writew(void *opaque, uint32_t addr, uint32_t val) } } port->ctrl &= UHCI_PORT_READ_ONLY; + /* enabled may only be set if a device is connected */ + if (!(port->ctrl & UHCI_PORT_CCS)) { + val &= ~UHCI_PORT_EN; + } port->ctrl |= (val & ~UHCI_PORT_READ_ONLY); /* some bits are reset when a '1' is written to them */ port->ctrl &= ~(val & UHCI_PORT_WRITE_CLEAR); -- cgit v1.2.1