[Qemu-devel] [PATCH 27/36] uhci: Detect guest td re-use

[Gerd Hoffmann <kraxel@redhat.com>]

From: Hans de Goede <hdegoede@redhat.com>

A td can be reused by the guest in a different queue, before we notice
the original queue has been unlinked. So search for tds by addr only, detect
guest td reuse, and cancel the original queue, this is necessary to keep our
packet ids unique.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/hcd-uhci.c |   33 ++++++++++++++++-----------------
 1 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index 0984bee..c4f2f98 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -319,28 +319,18 @@ static void uhci_async_cancel_all(UHCIState *s)
     }
 }
 
-static UHCIAsync *uhci_async_find_td(UHCIState *s, uint32_t td_addr,
-                                     UHCI_TD *td)
+static UHCIAsync *uhci_async_find_td(UHCIState *s, uint32_t td_addr)
 {
-    uint32_t token = uhci_queue_token(td);
     UHCIQueue *queue;
     UHCIAsync *async;
 
     QTAILQ_FOREACH(queue, &s->queues, next) {
-        if (queue->token == token) {
-            break;
-        }
-    }
-    if (queue == NULL) {
-        return NULL;
-    }
-
-    QTAILQ_FOREACH(async, &queue->asyncs, next) {
-        if (async->td_addr == td_addr) {
-            return async;
+        QTAILQ_FOREACH(async, &queue->asyncs, next) {
+            if (async->td_addr == td_addr) {
+                return async;
+            }
         }
     }
-
     return NULL;
 }
 
@@ -805,11 +795,21 @@ out:
 static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
                           UHCI_TD *td, uint32_t td_addr, uint32_t *int_mask)
 {
-    UHCIAsync *async;
     int len = 0, max_len;
     bool spd;
     bool queuing = (q != NULL);
     uint8_t pid = td->token & 0xff;
+    UHCIAsync *async = uhci_async_find_td(s, td_addr);
+
+    if (async) {
+        if (uhci_queue_verify(async->queue, qh_addr, td, td_addr, queuing)) {
+            assert(q == NULL || q == async->queue);
+            q = async->queue;
+        } else {
+            uhci_queue_free(async->queue, "guest re-used pending td");
+            async = NULL;
+        }
+    }
 
     if (q == NULL) {
         q = uhci_queue_find(s, td);
@@ -831,7 +831,6 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
         return TD_RESULT_NEXT_QH;
     }
 
-    async = uhci_async_find_td(s, td_addr, td);
     if (async) {
         /* Already submitted */
         async->queue->valid = 32;
-- 
1.7.1