[Xen-changelog] [qemu-upstream-unstable] uhci: Don't allow the guest to set port-enabled when there is no dev connected

[patchbot@xxxxxxx]

commit 1cbdde909f70fd15ff85f068a6318b73865c7fa3
Author: Hans de Goede <hdegoede@xxxxxxxxxx>
Date:   Sat Nov 17 12:11:50 2012 +0100

    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 <hdegoede@xxxxxxxxxx>
    Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
 hw/usb/hcd-uhci.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index ef32633..078be2a 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);
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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