usb: split packet result into actual_length + status

Since with the ehci and xhci controllers a single packet can be larger
then maxpacketsize, it is possible for the result of a single packet
to be both having transferred some data as well as the transfer to have
an error.

An example would be an input transfer from a bulk endpoint successfully
receiving 1 or more maxpacketsize packets from the device, followed
by a packet signalling halt.

While already touching all the devices and controllers handle_packet /
handle_data / handle_control code, also change the return type of
these functions to void, solely storing the status in the packet. To
make the code paths for regular versus async packet handling more
uniform.

This patch unfortunately is somewhat invasive, since makeing the qemu
usb core deal with this requires changes everywhere. This patch only
prepares the usb core for this, all the hcd / device changes are done
in such a way that there are no functional changes.

This patch has been tested with uhci and ehci hcds, together with usb-audio,
usb-hid and usb-storage devices, as well as with usb-redir redirection
with a wide variety of real devices.

Note that there is usually no need to directly set packet->actual_length
form devices handle_data callback, as that is done by usb_packet_copy()

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 16 insertions, 10 deletions

diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index d9dc576e7c..3a1f5134ea 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -1163,7 +1163,7 @@ static void ehci_async_complete_packet(USBPort *port, USBPacket *packet)
     p = container_of(packet, EHCIPacket, packet);
     assert(p->async == EHCI_ASYNC_INFLIGHT);
 
-    if (packet->result == USB_RET_REMOVE_FROM_QUEUE) {
+    if (packet->status == USB_RET_REMOVE_FROM_QUEUE) {
         trace_usb_ehci_packet_action(p->queue, p, "remove");
         ehci_free_packet(p);
         return;
@@ -1171,7 +1171,7 @@ static void ehci_async_complete_packet(USBPort *port, USBPacket *packet)
 
     trace_usb_ehci_packet_action(p->queue, p, "wakeup");
     p->async = EHCI_ASYNC_FINISHED;
-    p->usb_status = packet->result;
+    p->usb_status = packet->status ? packet->status : packet->actual_length;
 
     if (p->queue->async) {
         qemu_bh_schedule(p->queue->ehci->async_bh);
@@ -1253,7 +1253,6 @@ static void ehci_execute_complete(EHCIQueue *q)
 static int ehci_execute(EHCIPacket *p, const char *action)
 {
     USBEndpoint *ep;
-    int ret;
     int endp;
     bool spd;
 
@@ -1303,17 +1302,22 @@ static int ehci_execute(EHCIPacket *p, const char *action)
     }
 
     trace_usb_ehci_packet_action(p->queue, p, action);
-    ret = usb_handle_packet(p->queue->dev, &p->packet);
-    DPRINTF("submit: qh %x next %x qtd %x pid %x len %zd endp %x ret %d\n",
-            q->qhaddr, q->qh.next, q->qtdaddr, q->pid,
-            q->packet.iov.size, endp, ret);
+    usb_handle_packet(p->queue->dev, &p->packet);
+    DPRINTF("submit: qh 0x%x next 0x%x qtd 0x%x pid 0x%x len %zd endp 0x%x "
+            "status %d actual_length %d\n", p->queue->qhaddr, p->qtd.next,
+            p->qtdaddr, p->pid, p->packet.iov.size, endp, p->packet.status,
+            p->packet.actual_length);
 
-    if (ret > BUFF_SIZE) {
+    if (p->packet.actual_length > BUFF_SIZE) {
         fprintf(stderr, "ret from usb_handle_packet > BUFF_SIZE\n");
         return USB_RET_PROCERR;
     }
 
-    return ret;
+    if (p->packet.status == USB_RET_SUCCESS) {
+        return p->packet.actual_length;
+    } else {
+        return p->packet.status;
+    }
 }
 
 /*  4.7.2
@@ -1370,8 +1374,10 @@ static int ehci_process_itd(EHCIState *ehci,
                 usb_packet_setup(&ehci->ipacket, pid, ep, addr, false,
                                  (itd->transact[i] & ITD_XACT_IOC) != 0);
                 usb_packet_map(&ehci->ipacket, &ehci->isgl);
-                ret = usb_handle_packet(dev, &ehci->ipacket);
+                usb_handle_packet(dev, &ehci->ipacket);
                 usb_packet_unmap(&ehci->ipacket, &ehci->isgl);
+                ret = (ehci->ipacket.status == USB_RET_SUCCESS) ?
+                      ehci->ipacket.actual_length : ehci->ipacket.status;
             } else {
                 DPRINTF("ISOCH: attempt to addess non-iso endpoint\n");
                 ret = USB_RET_NAK;