hw: ehci: check return value of 'usb_packet_map'

If 'usb_packet_map' fails, we should stop to process the usb
request.

Signed-off-by: Li Qiang <liq3ea@163.com>
Message-Id: <20200812161727.29412-1-liq3ea@163.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-ehci.c

@@ -1373,7 +1373,10 @@ static int ehci_execute(EHCIPacket *p, const char *action)
         spd = (p->pid == USB_TOKEN_IN && NLPTR_TBIT(p->qtd.altnext) == 0);
         usb_packet_setup(&p->packet, p->pid, ep, 0, p->qtdaddr, spd,
                          (p->qtd.token & QTD_TOKEN_IOC) != 0);
-        usb_packet_map(&p->packet, &p->sgl);
+        if (usb_packet_map(&p->packet, &p->sgl)) {
+            qemu_sglist_destroy(&p->sgl);
+            return -1;
+        }
         p->async = EHCI_ASYNC_INITIALIZED;
     }
 
@@ -1453,7 +1456,10 @@ static int ehci_process_itd(EHCIState *ehci,
             if (ep && ep->type == USB_ENDPOINT_XFER_ISOC) {
                 usb_packet_setup(&ehci->ipacket, pid, ep, 0, addr, false,
                                  (itd->transact[i] & ITD_XACT_IOC) != 0);
-                usb_packet_map(&ehci->ipacket, &ehci->isgl);
+                if (usb_packet_map(&ehci->ipacket, &ehci->isgl)) {
+                    qemu_sglist_destroy(&ehci->isgl);
+                    return -1;
+                }
                 usb_handle_packet(dev, &ehci->ipacket);
                 usb_packet_unmap(&ehci->ipacket, &ehci->isgl);
             } else {