[Qemu-devel] [PATCH 03/32] ehci: Verify guest does not change the token of inflight qtd-s

[Gerd Hoffmann <kraxel@redhat.com>]

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

This is not allowed, except for clearing active on cancellation, so don't
warn when the new token does not have its active bit set.

This unifies the cancellation path for modified qtd-s, and prepares
ehci_verify_qtd to be used ad an extra check inside
ehci_writeback_async_complete_packet().

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/hcd-ehci.c |   10 ++++------
 1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 0d31597..04301ce 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -461,6 +461,7 @@ static bool ehci_verify_qtd(EHCIPacket *p, EHCIqtd *qtd)
         (p->queue->async && !NLPTR_TBIT(p->qtd.next) &&
             (p->qtd.next != qtd->next)) ||
         (!NLPTR_TBIT(p->qtd.altnext) && (p->qtd.altnext != qtd->altnext)) ||
+        p->qtd.token != qtd->token ||
         p->qtd.bufptr[0] != qtd->bufptr[0]) {
         return false;
     } else {
@@ -1793,7 +1794,9 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
     if (p != NULL) {
         if (!ehci_verify_qtd(p, &qtd)) {
             ehci_cancel_queue(q);
-            ehci_trace_guest_bug(q->ehci, "guest updated active QH or qTD");
+            if (qtd.token & QTD_TOKEN_ACTIVE) {
+                ehci_trace_guest_bug(q->ehci, "guest updated active qTD");
+            }
             p = NULL;
         } else {
             p->qtd = qtd;
@@ -1802,11 +1805,6 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
     }
 
     if (!(qtd.token & QTD_TOKEN_ACTIVE)) {
-        if (p != NULL) {
-            /* transfer canceled by guest (clear active) */
-            ehci_cancel_queue(q);
-            p = NULL;
-        }
         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
     } else if (p != NULL) {
         switch (p->async) {
-- 
1.7.1