xhci: flush dequeue pointer to endpoint context

When done processing a endpoint ring we must update the dequeue pointer
in the endpoint context in guest memory.  This is needed to make sure
the guest has a correct view of things and also to make live migration
work properly, because xhci post_load restores alot of the state from
xhci data structures in guest memory.

Add xhci_set_ep_state() call to do that.

The recursive calls stopped by commit
ddb603ab6c981c1d67cb42266fc700c33e5b2d8f had the (unintentional) side
effect to hiding this bug.  xhci_set_ep_state() was called before
processing, to set the state to running, which updated the dequeue
pointer too.

Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: 20170331102521.29253-1-kraxel@redhat.com

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index f0af8527098ae943b152e47ab9368a95845818ce..a2d3143bf492d042b8b3a0896d1fce49b1f0c652 100644 (file)
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -2063,7 +2063,7 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid,
 static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
 {
     XHCIState *xhci = epctx->xhci;
-    XHCIStreamContext *stctx;
+    XHCIStreamContext *stctx = NULL;
     XHCITransfer *xfer;
     XHCIRing *ring;
     USBEndpoint *ep = NULL;
@@ -2186,6 +2186,8 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid)
             break;
         }
     }
+    /* update ring dequeue ptr */
+    xhci_set_ep_state(xhci, epctx, stctx, epctx->state);
     epctx->kick_active--;
 
     ep = xhci_epid_to_usbep(epctx);