[PATCH v3 3/3] hw/usb/hcd-ehci: Handle get_dwords() failures in async writeback

[Jamin Lin <jamin_lin@aspeedtech.com>]

Coverity reports that ehci_writeback_async_complete_packet() ignores
the return value of get_dwords() when reading the QH and qTD.

Handle read failures in the same way as QH and qTD verification
failures by freeing the packet and returning early.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Resolves: Coverity CID 1685236
Fixes: 2b3de6ada5d ("ehci: writeback_async_complete_packet: verify qh and qtd")
Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
---
 hw/usb/hcd-ehci.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 5187ecc7e4..f371e567f3 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -527,11 +527,11 @@ static void ehci_writeback_async_complete_packet(EHCIPacket *p)
     /* Verify the qh + qtd, like we do when going through fetchqh & fetchqtd */
     memset(&qh, 0, sizeof(qh));
     memset(&qtd, 0, sizeof(qtd));
-    get_dwords(q->ehci, NLPTR_GET(q->qhaddr),
-               (uint32_t *) &qh, ehci_qh_dwords(q->ehci));
-    get_dwords(q->ehci, NLPTR_GET(q->qtdaddr),
-               (uint32_t *) &qtd, ehci_qtd_dwords(q->ehci));
-    if (!ehci_verify_qh(q, &qh) || !ehci_verify_qtd(p, &qtd)) {
+    if (!get_dwords(q->ehci, NLPTR_GET(q->qhaddr),
+                    (uint32_t *) &qh, ehci_qh_dwords(q->ehci)) ||
+        !get_dwords(q->ehci, NLPTR_GET(q->qtdaddr),
+                    (uint32_t *) &qtd, ehci_qtd_dwords(q->ehci)) ||
+        !ehci_verify_qh(q, &qh) || !ehci_verify_qtd(p, &qtd)) {
         p->async = EHCI_ASYNC_INITIALIZED;
         ehci_free_packet(p);
         return;
-- 
2.53.0