Merge remote-tracking branch 'kraxel/usb.70' into staging

* kraxel/usb.70:
  ehci: fix migration
  xhci: Fix some DMA host endian bugs
  usb/combined-packet: Move freeing of combined to usb_combined_packet_remove()
  xhci: Add support for packets with both data and an error status
  ehci: Add support for packets with both data and an error status
  ehci: Get rid of the magical PROC_ERR status
  usb-redir: Allow packets to have both data and an error-status
  usb: split packet result into actual_length + status

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

26 files changed, 775 insertions, 797 deletions

diff --git a/hw/usb.h b/hw/usb.h
index aef07f4..7d6de69 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -38,6 +38,7 @@
 #define USB_TOKEN_IN    0x69 /* device -> host */
 #define USB_TOKEN_OUT   0xe1 /* host -> device */
 
+#define USB_RET_SUCCESS           (0)
 #define USB_RET_NODEV             (-1)
 #define USB_RET_NAK               (-2)
 #define USB_RET_STALL             (-3)
@@ -280,18 +281,20 @@ typedef struct USBDeviceClass {
      * Process control request.
      * Called from handle_packet().
      *
-     * Returns length or one of the USB_RET_ codes.
+     * Status gets stored in p->status, and if p->status == USB_RET_SUCCESS
+     * then the number of bytes transfered is stored in p->actual_length
      */
-    int (*handle_control)(USBDevice *dev, USBPacket *p, int request, int value,
-                          int index, int length, uint8_t *data);
+    void (*handle_control)(USBDevice *dev, USBPacket *p, int request, int value,
+                           int index, int length, uint8_t *data);
 
     /*
      * Process data transfers (both BULK and ISOC).
      * Called from handle_packet().
      *
-     * Returns length or one of the USB_RET_ codes.
+     * Status gets stored in p->status, and if p->status == USB_RET_SUCCESS
+     * then the number of bytes transfered is stored in p->actual_length
      */
-    int (*handle_data)(USBDevice *dev, USBPacket *p);
+    void (*handle_data)(USBDevice *dev, USBPacket *p);
 
     void (*set_interface)(USBDevice *dev, int interface,
                           int alt_old, int alt_new);
@@ -354,7 +357,8 @@ struct USBPacket {
     uint64_t parameter; /* control transfers */
     bool short_not_ok;
     bool int_req;
-    int result; /* transfer length or USB_RET_* status code */
+    int status; /* USB_RET_* status code */
+    int actual_length; /* Number of bytes actually transfered */
     /* Internal use by the USB layer.  */
     USBPacketState state;
     USBCombinedPacket *combined;
@@ -388,7 +392,7 @@ static inline bool usb_packet_is_inflight(USBPacket *p)
 
 USBDevice *usb_find_device(USBPort *port, uint8_t addr);
 
-int usb_handle_packet(USBDevice *dev, USBPacket *p);
+void usb_handle_packet(USBDevice *dev, USBPacket *p);
 void usb_packet_complete(USBDevice *dev, USBPacket *p);
 void usb_packet_complete_one(USBDevice *dev, USBPacket *p);
 void usb_cancel_packet(USBPacket * p);
@@ -523,10 +527,10 @@ void usb_device_handle_attach(USBDevice *dev);
 
 void usb_device_handle_reset(USBDevice *dev);
 
-int usb_device_handle_control(USBDevice *dev, USBPacket *p, int request, int value,
-                              int index, int length, uint8_t *data);
+void usb_device_handle_control(USBDevice *dev, USBPacket *p, int request,
+                               int val, int index, int length, uint8_t *data);
 
-int usb_device_handle_data(USBDevice *dev, USBPacket *p);
+void usb_device_handle_data(USBDevice *dev, USBPacket *p);
 
 void usb_device_set_interface(USBDevice *dev, int interface,
                               int alt_old, int alt_new);
diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index 8066291..99aac7a 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -140,24 +140,21 @@ void usb_device_handle_reset(USBDevice *dev)
     }
 }
 
-int usb_device_handle_control(USBDevice *dev, USBPacket *p, int request,
-                              int value, int index, int length, uint8_t *data)
+void usb_device_handle_control(USBDevice *dev, USBPacket *p, int request,
+                               int value, int index, int length, uint8_t *data)
 {
     USBDeviceClass *klass = USB_DEVICE_GET_CLASS(dev);
     if (klass->handle_control) {
-        return klass->handle_control(dev, p, request, value, index, length,
-                                         data);
+        klass->handle_control(dev, p, request, value, index, length, data);
     }
-    return -ENOSYS;
 }
 
-int usb_device_handle_data(USBDevice *dev, USBPacket *p)
+void usb_device_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBDeviceClass *klass = USB_DEVICE_GET_CLASS(dev);
     if (klass->handle_data) {
-        return klass->handle_data(dev, p);
+        klass->handle_data(dev, p);
     }
-    return -ENOSYS;
 }
 
 const char *usb_device_get_product_desc(USBDevice *dev)
diff --git a/hw/usb/combined-packet.c b/hw/usb/combined-packet.c
index 3904e71..4a0c299 100644
--- a/hw/usb/combined-packet.c
+++ b/hw/usb/combined-packet.c
@@ -31,12 +31,16 @@ static void usb_combined_packet_add(USBCombinedPacket *combined, USBPacket *p)
     p->combined = combined;
 }
 
+/* Note will free combined when the last packet gets removed */
 static void usb_combined_packet_remove(USBCombinedPacket *combined,
                                        USBPacket *p)
 {
     assert(p->combined == combined);
     p->combined = NULL;
     QTAILQ_REMOVE(&combined->packets, p, combined_entry);
+    if (QTAILQ_EMPTY(&combined->packets)) {
+        g_free(combined);
+    }
 }
 
 /* Also handles completion of non combined packets for pipelined input eps */
@@ -45,9 +49,8 @@ void usb_combined_input_packet_complete(USBDevice *dev, USBPacket *p)
     USBCombinedPacket *combined = p->combined;
     USBEndpoint *ep = p->ep;
     USBPacket *next;
-    enum { completing, complete, leftover };
-    int result, state = completing;
-    bool short_not_ok;
+    int status, actual_length;
+    bool short_not_ok, done = false;
 
     if (combined == NULL) {
         usb_packet_complete_one(dev, p);
@@ -56,37 +59,39 @@ void usb_combined_input_packet_complete(USBDevice *dev, USBPacket *p)
 
     assert(combined->first == p && p == QTAILQ_FIRST(&combined->packets));
 
-    result = combined->first->result;
+    status = combined->first->status;
+    actual_length = combined->first->actual_length;
     short_not_ok = QTAILQ_LAST(&combined->packets, packets_head)->short_not_ok;
 
     QTAILQ_FOREACH_SAFE(p, &combined->packets, combined_entry, next) {
-        if (state == completing) {
+        if (!done) {
             /* Distribute data over uncombined packets */
-            if (result >= p->iov.size) {
-                p->result = p->iov.size;
+            if (actual_length >= p->iov.size) {
+                p->actual_length = p->iov.size;
             } else {
                 /* Send short or error packet to complete the transfer */
-                p->result = result;
-                state = complete;
+                p->actual_length = actual_length;
+                done = true;
+            }
+            /* Report status on the last packet */
+            if (done || next == NULL) {
+                p->status = status;
+            } else {
+                p->status = USB_RET_SUCCESS;
             }
             p->short_not_ok = short_not_ok;
+            /* Note will free combined when the last packet gets removed! */
             usb_combined_packet_remove(combined, p);
             usb_packet_complete_one(dev, p);
-            result -= p->result;
+            actual_length -= p->actual_length;
         } else {
             /* Remove any leftover packets from the queue */
-            state = leftover;
-            p->result = USB_RET_REMOVE_FROM_QUEUE;
+            p->status = USB_RET_REMOVE_FROM_QUEUE;
+            /* Note will free combined on the last packet! */
             dev->port->ops->complete(dev->port, p);
         }
     }
-    /*
-     * If we had leftover packets the hcd driver will have cancelled them
-     * and usb_combined_packet_cancel has already freed combined!
-     */
-    if (state != leftover) {
-        g_free(combined);
-    }
+    /* Do not use combined here, it has been freed! */
 leave:
     /* Check if there are packets in the queue waiting for our completion */
     usb_ep_combine_input_packets(ep);
@@ -97,14 +102,13 @@ void usb_combined_packet_cancel(USBDevice *dev, USBPacket *p)
 {
     USBCombinedPacket *combined = p->combined;
     assert(combined != NULL);
+    USBPacket *first = p->combined->first;
 
+    /* Note will free combined on the last packet! */
     usb_combined_packet_remove(combined, p);
-    if (p == combined->first) {
+    if (p == first) {
         usb_device_cancel_packet(dev, p);
     }
-    if (QTAILQ_EMPTY(&combined->packets)) {
-        g_free(combined);
-    }
 }
 
 /*
@@ -117,7 +121,7 @@ void usb_ep_combine_input_packets(USBEndpoint *ep)
 {
     USBPacket *p, *u, *next, *prev = NULL, *first = NULL;
     USBPort *port = ep->dev->port;
-    int ret, totalsize;
+    int totalsize;
 
     assert(ep->pipeline);
     assert(ep->pid == USB_TOKEN_IN);
@@ -125,7 +129,7 @@ void usb_ep_combine_input_packets(USBEndpoint *ep)
     QTAILQ_FOREACH_SAFE(p, &ep->queue, queue, next) {
         /* Empty the queue on a halt */
         if (ep->halted) {
-            p->result = USB_RET_REMOVE_FROM_QUEUE;
+            p->status = USB_RET_REMOVE_FROM_QUEUE;
             port->ops->complete(port, p);
             continue;
         }
@@ -166,8 +170,8 @@ void usb_ep_combine_input_packets(USBEndpoint *ep)
                 next == NULL ||
                 /* Work around for Linux usbfs bulk splitting + migration */
                 (totalsize == 16348 && p->int_req)) {
-            ret = usb_device_handle_data(ep->dev, first);
-            assert(ret == USB_RET_ASYNC);
+            usb_device_handle_data(ep->dev, first);
+            assert(first->status == USB_RET_ASYNC);
             if (first->combined) {
                 QTAILQ_FOREACH(u, &first->combined->packets, combined_entry) {
                     usb_packet_set_state(u, USB_PACKET_ASYNC);
diff --git a/hw/usb/core.c b/hw/usb/core.c
index ab37f6f..52b5310 100644
--- a/hw/usb/core.c
+++ b/hw/usb/core.c
@@ -97,17 +97,17 @@ void usb_wakeup(USBEndpoint *ep)
 #define SETUP_STATE_ACK   3
 #define SETUP_STATE_PARAM 4
 
-static int do_token_setup(USBDevice *s, USBPacket *p)
+static void do_token_setup(USBDevice *s, USBPacket *p)
 {
     int request, value, index;
-    int ret = 0;
 
     if (p->iov.size != 8) {
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
 
     usb_packet_copy(p, s->setup_buf, p->iov.size);
-    p->result = 0;
+    p->actual_length = 0;
     s->setup_len   = (s->setup_buf[7] << 8) | s->setup_buf[6];
     s->setup_index = 0;
 
@@ -116,24 +116,26 @@ static int do_token_setup(USBDevice *s, USBPacket *p)
     index   = (s->setup_buf[5] << 8) | s->setup_buf[4];
 
     if (s->setup_buf[0] & USB_DIR_IN) {
-        ret = usb_device_handle_control(s, p, request, value, index,
-                                        s->setup_len, s->data_buf);
-        if (ret == USB_RET_ASYNC) {
-             s->setup_state = SETUP_STATE_SETUP;
-             return USB_RET_ASYNC;
+        usb_device_handle_control(s, p, request, value, index,
+                                  s->setup_len, s->data_buf);
+        if (p->status == USB_RET_ASYNC) {
+            s->setup_state = SETUP_STATE_SETUP;
+        }
+        if (p->status != USB_RET_SUCCESS) {
+            return;
         }
-        if (ret < 0)
-            return ret;
 
-        if (ret < s->setup_len)
-            s->setup_len = ret;
+        if (p->actual_length < s->setup_len) {
+            s->setup_len = p->actual_length;
+        }
         s->setup_state = SETUP_STATE_DATA;
     } else {
         if (s->setup_len > sizeof(s->data_buf)) {
             fprintf(stderr,
                 "usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
                 s->setup_len, sizeof(s->data_buf));
-            return USB_RET_STALL;
+            p->status = USB_RET_STALL;
+            return;
         }
         if (s->setup_len == 0)
             s->setup_state = SETUP_STATE_ACK;
@@ -141,13 +143,12 @@ static int do_token_setup(USBDevice *s, USBPacket *p)
             s->setup_state = SETUP_STATE_DATA;
     }
 
-    return ret;
+    p->actual_length = 8;
 }
 
-static int do_token_in(USBDevice *s, USBPacket *p)
+static void do_token_in(USBDevice *s, USBPacket *p)
 {
     int request, value, index;
-    int ret = 0;
 
     assert(p->ep->nr == 0);
 
@@ -158,19 +159,15 @@ static int do_token_in(USBDevice *s, USBPacket *p)
     switch(s->setup_state) {
     case SETUP_STATE_ACK:
         if (!(s->setup_buf[0] & USB_DIR_IN)) {
-            ret = usb_device_handle_control(s, p, request, value, index,
-                                            s->setup_len, s->data_buf);
-            if (ret == USB_RET_ASYNC) {
-                return USB_RET_ASYNC;
+            usb_device_handle_control(s, p, request, value, index,
+                                      s->setup_len, s->data_buf);
+            if (p->status == USB_RET_ASYNC) {
+                return;
             }
             s->setup_state = SETUP_STATE_IDLE;
-            if (ret > 0)
-                return 0;
-            return ret;
+            p->actual_length = 0;
         }
-
-        /* return 0 byte */
-        return 0;
+        break;
 
     case SETUP_STATE_DATA:
         if (s->setup_buf[0] & USB_DIR_IN) {
@@ -180,20 +177,21 @@ static int do_token_in(USBDevice *s, USBPacket *p)
             }
             usb_packet_copy(p, s->data_buf + s->setup_index, len);
             s->setup_index += len;
-            if (s->setup_index >= s->setup_len)
+            if (s->setup_index >= s->setup_len) {
                 s->setup_state = SETUP_STATE_ACK;
-            return len;
+            }
+            return;
         }
-
         s->setup_state = SETUP_STATE_IDLE;
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        break;
 
     default:
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
     }
 }
 
-static int do_token_out(USBDevice *s, USBPacket *p)
+static void do_token_out(USBDevice *s, USBPacket *p)
 {
     assert(p->ep->nr == 0);
 
@@ -205,7 +203,7 @@ static int do_token_out(USBDevice *s, USBPacket *p)
         } else {
             /* ignore additional output */
         }
-        return 0;
+        break;
 
     case SETUP_STATE_DATA:
         if (!(s->setup_buf[0] & USB_DIR_IN)) {
@@ -215,23 +213,23 @@ static int do_token_out(USBDevice *s, USBPacket *p)
             }
             usb_packet_copy(p, s->data_buf + s->setup_index, len);
             s->setup_index += len;
-            if (s->setup_index >= s->setup_len)
+            if (s->setup_index >= s->setup_len) {
                 s->setup_state = SETUP_STATE_ACK;
-            return len;
+            }
+            return;
         }
-
         s->setup_state = SETUP_STATE_IDLE;
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        break;
 
     default:
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
     }
 }
 
-static int do_parameter(USBDevice *s, USBPacket *p)
+static void do_parameter(USBDevice *s, USBPacket *p)
 {
-    int request, value, index;
-    int i, ret = 0;
+    int i, request, value, index;
 
     for (i = 0; i < 8; i++) {
         s->setup_buf[i] = p->parameter >> (i*8);
@@ -249,27 +247,27 @@ static int do_parameter(USBDevice *s, USBPacket *p)
         fprintf(stderr,
                 "usb_generic_handle_packet: ctrl buffer too small (%d > %zu)\n",
                 s->setup_len, sizeof(s->data_buf));
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
 
     if (p->pid == USB_TOKEN_OUT) {
         usb_packet_copy(p, s->data_buf, s->setup_len);
     }
 
-    ret = usb_device_handle_control(s, p, request, value, index,
-                                    s->setup_len, s->data_buf);
-    if (ret < 0) {
-        return ret;
+    usb_device_handle_control(s, p, request, value, index,
+                              s->setup_len, s->data_buf);
+    if (p->status == USB_RET_ASYNC) {
+        return;
     }
 
-    if (ret < s->setup_len) {
-        s->setup_len = ret;
+    if (p->actual_length < s->setup_len) {
+        s->setup_len = p->actual_length;
     }
     if (p->pid == USB_TOKEN_IN) {
+        p->actual_length = 0;
         usb_packet_copy(p, s->data_buf, s->setup_len);
     }
-
-    return ret;
 }
 
 /* ctrl complete function for devices which use usb_generic_handle_packet and
@@ -278,30 +276,30 @@ static int do_parameter(USBDevice *s, USBPacket *p)
    usb_packet_complete to complete their async control packets. */
 void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p)
 {
-    if (p->result < 0) {
+    if (p->status < 0) {
         s->setup_state = SETUP_STATE_IDLE;
     }
 
     switch (s->setup_state) {
     case SETUP_STATE_SETUP:
-        if (p->result < s->setup_len) {
-            s->setup_len = p->result;
+        if (p->actual_length < s->setup_len) {
+            s->setup_len = p->actual_length;
         }
         s->setup_state = SETUP_STATE_DATA;
-        p->result = 8;
+        p->actual_length = 8;
         break;
 
     case SETUP_STATE_ACK:
         s->setup_state = SETUP_STATE_IDLE;
-        p->result = 0;
+        p->actual_length = 0;
         break;
 
     case SETUP_STATE_PARAM:
-        if (p->result < s->setup_len) {
-            s->setup_len = p->result;
+        if (p->actual_length < s->setup_len) {
+            s->setup_len = p->actual_length;
         }
         if (p->pid == USB_TOKEN_IN) {
-            p->result = 0;
+            p->actual_length = 0;
             usb_packet_copy(p, s->data_buf, s->setup_len);
         }
         break;
@@ -342,40 +340,57 @@ USBDevice *usb_find_device(USBPort *port, uint8_t addr)
     return usb_device_find_device(dev, addr);
 }
 
-static int usb_process_one(USBPacket *p)
+static void usb_process_one(USBPacket *p)
 {
     USBDevice *dev = p->ep->dev;
 
+    /*
+     * Handlers expect status to be initialized to USB_RET_SUCCESS, but it
+     * can be USB_RET_NAK here from a previous usb_process_one() call,
+     * or USB_RET_ASYNC from going through usb_queue_one().
+     */
+    p->status = USB_RET_SUCCESS;
+
     if (p->ep->nr == 0) {
         /* control pipe */
         if (p->parameter) {
-            return do_parameter(dev, p);
+            do_parameter(dev, p);
+            return;
         }
         switch (p->pid) {
         case USB_TOKEN_SETUP:
-            return do_token_setup(dev, p);
+            do_token_setup(dev, p);
+            break;
         case USB_TOKEN_IN:
-            return do_token_in(dev, p);
+            do_token_in(dev, p);
+            break;
         case USB_TOKEN_OUT:
-            return do_token_out(dev, p);
+            do_token_out(dev, p);
+            break;
         default:
-            return USB_RET_STALL;
+            p->status = USB_RET_STALL;
         }
     } else {
         /* data pipe */
-        return usb_device_handle_data(dev, p);
+        usb_device_handle_data(dev, p);
     }
 }
 
-/* Hand over a packet to a device for processing.  Return value
+static void usb_queue_one(USBPacket *p)
+{
+    usb_packet_set_state(p, USB_PACKET_QUEUED);
+    QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
+    p->status = USB_RET_ASYNC;
+}
+
+/* Hand over a packet to a device for processing.  p->status ==
    USB_RET_ASYNC indicates the processing isn't finished yet, the
    driver will call usb_packet_complete() when done processing it. */
-int usb_handle_packet(USBDevice *dev, USBPacket *p)
+void usb_handle_packet(USBDevice *dev, USBPacket *p)
 {
-    int ret;
-
     if (dev == NULL) {
-        return USB_RET_NODEV;
+        p->status = USB_RET_NODEV;
+        return;
     }
     assert(dev == p->ep->dev);
     assert(dev->state == USB_STATE_DEFAULT);
@@ -389,32 +404,26 @@ int usb_handle_packet(USBDevice *dev, USBPacket *p)
     }
 
     if (QTAILQ_EMPTY(&p->ep->queue) || p->ep->pipeline) {
-        ret = usb_process_one(p);
-        if (ret == USB_RET_ASYNC) {
+        usb_process_one(p);
+        if (p->status == USB_RET_ASYNC) {
             assert(p->ep->type != USB_ENDPOINT_XFER_ISOC);
             usb_packet_set_state(p, USB_PACKET_ASYNC);
             QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
-        } else if (ret == USB_RET_ADD_TO_QUEUE) {
-            usb_packet_set_state(p, USB_PACKET_QUEUED);
-            QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
-            ret = USB_RET_ASYNC;
+        } else if (p->status == USB_RET_ADD_TO_QUEUE) {
+            usb_queue_one(p);
         } else {
             /*
              * When pipelining is enabled usb-devices must always return async,
              * otherwise packets can complete out of order!
              */
             assert(!p->ep->pipeline || QTAILQ_EMPTY(&p->ep->queue));
-            if (ret != USB_RET_NAK) {
-                p->result = ret;
+            if (p->status != USB_RET_NAK) {
                 usb_packet_set_state(p, USB_PACKET_COMPLETE);
             }
         }
     } else {
-        ret = USB_RET_ASYNC;
-        usb_packet_set_state(p, USB_PACKET_QUEUED);
-        QTAILQ_INSERT_TAIL(&p->ep->queue, p, queue);
+        usb_queue_one(p);
     }
-    return ret;
 }
 
 void usb_packet_complete_one(USBDevice *dev, USBPacket *p)
@@ -422,9 +431,10 @@ void usb_packet_complete_one(USBDevice *dev, USBPacket *p)
     USBEndpoint *ep = p->ep;
 
     assert(QTAILQ_FIRST(&ep->queue) == p);
-    assert(p->result != USB_RET_ASYNC && p->result != USB_RET_NAK);
+    assert(p->status != USB_RET_ASYNC && p->status != USB_RET_NAK);
 
-    if (p->result < 0 || (p->short_not_ok && (p->result < p->iov.size))) {
+    if (p->status != USB_RET_SUCCESS ||
+            (p->short_not_ok && (p->actual_length < p->iov.size))) {
         ep->halted = true;
     }
     usb_packet_set_state(p, USB_PACKET_COMPLETE);
@@ -438,7 +448,6 @@ void usb_packet_complete_one(USBDevice *dev, USBPacket *p)
 void usb_packet_complete(USBDevice *dev, USBPacket *p)
 {
     USBEndpoint *ep = p->ep;
-    int ret;
 
     usb_packet_check_state(p, USB_PACKET_ASYNC);
     usb_packet_complete_one(dev, p);
@@ -447,7 +456,7 @@ void usb_packet_complete(USBDevice *dev, USBPacket *p)
         p = QTAILQ_FIRST(&ep->queue);
         if (ep->halted) {
             /* Empty the queue on a halt */
-            p->result = USB_RET_REMOVE_FROM_QUEUE;
+            p->status = USB_RET_REMOVE_FROM_QUEUE;
             dev->port->ops->complete(dev->port, p);
             continue;
         }
@@ -455,12 +464,11 @@ void usb_packet_complete(USBDevice *dev, USBPacket *p)
             break;
         }
         usb_packet_check_state(p, USB_PACKET_QUEUED);
-        ret = usb_process_one(p);
-        if (ret == USB_RET_ASYNC) {
+        usb_process_one(p);
+        if (p->status == USB_RET_ASYNC) {
             usb_packet_set_state(p, USB_PACKET_ASYNC);
             break;
         }
-        p->result = ret;
         usb_packet_complete_one(ep->dev, p);
     }
 }
@@ -541,7 +549,8 @@ void usb_packet_setup(USBPacket *p, int pid, USBEndpoint *ep, uint64_t id,
     p->id = id;
     p->pid = pid;
     p->ep = ep;
-    p->result = 0;
+    p->status = USB_RET_SUCCESS;
+    p->actual_length = 0;
     p->parameter = 0;
     p->short_not_ok = short_not_ok;
     p->int_req = int_req;
@@ -557,31 +566,31 @@ void usb_packet_addbuf(USBPacket *p, void *ptr, size_t len)
 
 void usb_packet_copy(USBPacket *p, void *ptr, size_t bytes)
 {
-    assert(p->result >= 0);
-    assert(p->result + bytes <= p->iov.size);
+    assert(p->actual_length >= 0);
+    assert(p->actual_length + bytes <= p->iov.size);
     switch (p->pid) {
     case USB_TOKEN_SETUP:
     case USB_TOKEN_OUT:
-        iov_to_buf(p->iov.iov, p->iov.niov, p->result, ptr, bytes);
+        iov_to_buf(p->iov.iov, p->iov.niov, p->actual_length, ptr, bytes);
         break;
     case USB_TOKEN_IN:
-        iov_from_buf(p->iov.iov, p->iov.niov, p->result, ptr, bytes);
+        iov_from_buf(p->iov.iov, p->iov.niov, p->actual_length, ptr, bytes);
         break;
     default:
         fprintf(stderr, "%s: invalid pid: %x\n", __func__, p->pid);
         abort();
     }
-    p->result += bytes;
+    p->actual_length += bytes;
 }
 
 void usb_packet_skip(USBPacket *p, size_t bytes)
 {
-    assert(p->result >= 0);
-    assert(p->result + bytes <= p->iov.size);
+    assert(p->actual_length >= 0);
+    assert(p->actual_length + bytes <= p->iov.size);
     if (p->pid == USB_TOKEN_IN) {
-        iov_memset(p->iov.iov, p->iov.niov, p->result, 0, bytes);
+        iov_memset(p->iov.iov, p->iov.niov, p->actual_length, 0, bytes);
     }
-    p->result += bytes;
+    p->actual_length += bytes;
 }
 
 void usb_packet_cleanup(USBPacket *p)
diff --git a/hw/usb/desc.c b/hw/usb/desc.c
index 1f12eae..b7c3233 100644
--- a/hw/usb/desc.c
+++ b/hw/usb/desc.c
@@ -626,7 +626,8 @@ int usb_desc_string(USBDevice *dev, int index, uint8_t *dest, size_t len)
     return pos;
 }
 
-int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len)
+int usb_desc_get_descriptor(USBDevice *dev, USBPacket *p,
+                            int value, uint8_t *dest, size_t len)
 {
     const USBDesc *desc = usb_device_get_usb_desc(dev);
     const USBDescDevice *other_dev;
@@ -696,6 +697,8 @@ int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len
             ret = len;
         }
         memcpy(dest, buf, ret);
+        p->actual_length = ret;
+        ret = 0;
     }
     return ret;
 }
@@ -715,7 +718,7 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
         break;
 
     case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
-        ret = usb_desc_get_descriptor(dev, value, data, length);
+        ret = usb_desc_get_descriptor(dev, p, value, data, length);
         break;
 
     case DeviceRequest | USB_REQ_GET_CONFIGURATION:
@@ -724,7 +727,8 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
          * the non zero value of bConfigurationValue.
          */
         data[0] = dev->config ? dev->config->bConfigurationValue : 0;
-        ret = 1;
+        p->actual_length = 1;
+        ret = 0;
         break;
     case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
         ret = usb_desc_set_config(dev, value);
@@ -749,7 +753,8 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
             data[0] |= 1 << USB_DEVICE_REMOTE_WAKEUP;
         }
         data[1] = 0x00;
-        ret = 2;
+        p->actual_length = 2;
+        ret = 0;
         break;
     }
     case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
@@ -772,7 +777,8 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
             break;
         }
         data[0] = dev->altsetting[index];
-        ret = 1;
+        p->actual_length = 1;
+        ret = 0;
         break;
     case InterfaceOutRequest | USB_REQ_SET_INTERFACE:
         ret = usb_desc_set_interface(dev, index, value);
diff --git a/hw/usb/desc.h b/hw/usb/desc.h
index 68bb570..ddd3e74 100644
--- a/hw/usb/desc.h
+++ b/hw/usb/desc.h
@@ -216,7 +216,8 @@ void usb_desc_set_string(USBDevice *dev, uint8_t index, const char *str);
 void usb_desc_create_serial(USBDevice *dev);
 const char *usb_desc_get_string(USBDevice *dev, uint8_t index);
 int usb_desc_string(USBDevice *dev, int index, uint8_t *dest, size_t len);
-int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len);
+int usb_desc_get_descriptor(USBDevice *dev, USBPacket *p,
+        int value, uint8_t *dest, size_t len);
 int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
         int request, int value, int index, int length, uint8_t *data);
 
diff --git a/hw/usb/dev-audio.c b/hw/usb/dev-audio.c
index 2594c78..b669601 100644
--- a/hw/usb/dev-audio.c
+++ b/hw/usb/dev-audio.c
@@ -503,7 +503,7 @@ static int usb_audio_set_control(USBAudioState *s, uint8_t attrib,
     return ret;
 }
 
-static int usb_audio_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_audio_handle_control(USBDevice *dev, USBPacket *p,
                                     int request, int value, int index,
                                     int length, uint8_t *data)
 {
@@ -518,7 +518,7 @@ static int usb_audio_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
     switch (request) {
@@ -534,6 +534,7 @@ static int usb_audio_handle_control(USBDevice *dev, USBPacket *p,
             }
             goto fail;
         }
+        p->actual_length = ret;
         break;
 
     case ClassInterfaceOutRequest | CR_SET_CUR:
@@ -557,10 +558,9 @@ fail:
                     "request 0x%04x value 0x%04x index 0x%04x length 0x%04x\n",
                     request, value, index, length);
         }
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_audio_set_interface(USBDevice *dev, int iface,
@@ -583,50 +583,35 @@ static void usb_audio_handle_reset(USBDevice *dev)
     usb_audio_set_output_altset(s, ALTSET_OFF);
 }
 
-static int usb_audio_handle_dataout(USBAudioState *s, USBPacket *p)
+static void usb_audio_handle_dataout(USBAudioState *s, USBPacket *p)
 {
-    int rc;
-
     if (s->out.altset == ALTSET_OFF) {
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
 
-    rc = streambuf_put(&s->out.buf, p);
-    if (rc < p->iov.size && s->debug > 1) {
+    streambuf_put(&s->out.buf, p);
+    if (p->actual_length < p->iov.size && s->debug > 1) {
         fprintf(stderr, "usb-audio: output overrun (%zd bytes)\n",
-                p->iov.size - rc);
+                p->iov.size - p->actual_length);
     }
-
-    return 0;
 }
 
-static int usb_audio_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_audio_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBAudioState *s = (USBAudioState *) dev;
-    int ret = 0;
 
-    switch (p->pid) {
-    case USB_TOKEN_OUT:
-        switch (p->ep->nr) {
-        case 1:
-            ret = usb_audio_handle_dataout(s, p);
-            break;
-        default:
-            goto fail;
-        }
-        break;
-
-    default:
-fail:
-        ret = USB_RET_STALL;
-        break;
+    if (p->pid == USB_TOKEN_OUT && p->ep->nr == 1) {
+        usb_audio_handle_dataout(s, p);
+        return;
     }
-    if (ret == USB_RET_STALL && s->debug) {
+
+    p->status = USB_RET_STALL;
+    if (s->debug) {
         fprintf(stderr, "usb-audio: failed data transaction: "
                         "pid 0x%x ep 0x%x len 0x%zx\n",
                         p->pid, p->ep->nr, p->iov.size);
     }
-    return ret;
 }
 
 static void usb_audio_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/dev-bluetooth.c b/hw/usb/dev-bluetooth.c
index 55bc191..bfb96bf 100644
--- a/hw/usb/dev-bluetooth.c
+++ b/hw/usb/dev-bluetooth.c
@@ -285,13 +285,15 @@ static void usb_bt_fifo_enqueue(struct usb_hci_in_fifo_s *fifo,
     fifo->fifo[off].len = len;
 }
 
-static inline int usb_bt_fifo_dequeue(struct usb_hci_in_fifo_s *fifo,
+static inline void usb_bt_fifo_dequeue(struct usb_hci_in_fifo_s *fifo,
                 USBPacket *p)
 {
     int len;
 
-    if (likely(!fifo->len))
-        return USB_RET_STALL;
+    if (likely(!fifo->len)) {
+        p->status = USB_RET_STALL;
+        return;
+    }
 
     len = MIN(p->iov.size, fifo->fifo[fifo->start].len);
     usb_packet_copy(p, fifo->fifo[fifo->start].data, len);
@@ -310,8 +312,6 @@ static inline int usb_bt_fifo_dequeue(struct usb_hci_in_fifo_s *fifo,
         fifo->dstart = 0;
         fifo->dsize = DFIFO_LEN_MASK + 1;
     }
-
-    return len;
 }
 
 static inline void usb_bt_fifo_out_enqueue(struct USBBtState *s,
@@ -363,7 +363,7 @@ static void usb_bt_handle_reset(USBDevice *dev)
     s->outsco.len = 0;
 }
 
-static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_bt_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     struct USBBtState *s = (struct USBBtState *) dev->opaque;
@@ -382,16 +382,15 @@ static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
             usb_bt_fifo_reset(&s->sco);
             break;
         }
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case InterfaceRequest | USB_REQ_GET_STATUS:
     case EndpointRequest | USB_REQ_GET_STATUS:
         data[0] = 0x00;
         data[1] = 0x00;
-        ret = 2;
+        p->actual_length = 2;
         break;
     case InterfaceOutRequest | USB_REQ_CLEAR_FEATURE:
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
@@ -407,16 +406,14 @@ static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
         break;
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_bt_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_bt_handle_data(USBDevice *dev, USBPacket *p)
 {
     struct USBBtState *s = (struct USBBtState *) dev->opaque;
-    int ret = 0;
 
     if (!s->config)
         goto fail;
@@ -425,15 +422,15 @@ static int usb_bt_handle_data(USBDevice *dev, USBPacket *p)
     case USB_TOKEN_IN:
         switch (p->ep->nr) {
         case USB_EVT_EP:
-            ret = usb_bt_fifo_dequeue(&s->evt, p);
+            usb_bt_fifo_dequeue(&s->evt, p);
             break;
 
         case USB_ACL_EP:
-            ret = usb_bt_fifo_dequeue(&s->acl, p);
+            usb_bt_fifo_dequeue(&s->acl, p);
             break;
 
         case USB_SCO_EP:
-            ret = usb_bt_fifo_dequeue(&s->sco, p);
+            usb_bt_fifo_dequeue(&s->sco, p);
             break;
 
         default:
@@ -460,11 +457,9 @@ static int usb_bt_handle_data(USBDevice *dev, USBPacket *p)
 
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void usb_bt_out_hci_packet_event(void *opaque,
diff --git a/hw/usb/dev-hid.c b/hw/usb/dev-hid.c
index b3dcd23..55266b1 100644
--- a/hw/usb/dev-hid.c
+++ b/hw/usb/dev-hid.c
@@ -371,7 +371,7 @@ static void usb_hid_handle_reset(USBDevice *dev)
     hid_reset(&us->hid);
 }
 
-static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_hid_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBHIDState *us = DO_UPCAST(USBHIDState, dev, dev);
@@ -380,10 +380,9 @@ static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
         /* hid specific requests */
     case InterfaceRequest | USB_REQ_GET_DESCRIPTOR:
@@ -392,15 +391,15 @@ static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
             if (hs->kind == HID_MOUSE) {
 		memcpy(data, qemu_mouse_hid_report_descriptor,
 		       sizeof(qemu_mouse_hid_report_descriptor));
-		ret = sizeof(qemu_mouse_hid_report_descriptor);
+                p->actual_length = sizeof(qemu_mouse_hid_report_descriptor);
             } else if (hs->kind == HID_TABLET) {
                 memcpy(data, qemu_tablet_hid_report_descriptor,
 		       sizeof(qemu_tablet_hid_report_descriptor));
-		ret = sizeof(qemu_tablet_hid_report_descriptor);
+                p->actual_length = sizeof(qemu_tablet_hid_report_descriptor);
             } else if (hs->kind == HID_KEYBOARD) {
                 memcpy(data, qemu_keyboard_hid_report_descriptor,
                        sizeof(qemu_keyboard_hid_report_descriptor));
-                ret = sizeof(qemu_keyboard_hid_report_descriptor);
+                p->actual_length = sizeof(qemu_keyboard_hid_report_descriptor);
             }
             break;
         default:
@@ -409,14 +408,14 @@ static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
         break;
     case GET_REPORT:
         if (hs->kind == HID_MOUSE || hs->kind == HID_TABLET) {
-            ret = hid_pointer_poll(hs, data, length);
+            p->actual_length = hid_pointer_poll(hs, data, length);
         } else if (hs->kind == HID_KEYBOARD) {
-            ret = hid_keyboard_poll(hs, data, length);
+            p->actual_length = hid_keyboard_poll(hs, data, length);
         }
         break;
     case SET_REPORT:
         if (hs->kind == HID_KEYBOARD) {
-            ret = hid_keyboard_write(hs, data, length);
+            p->actual_length = hid_keyboard_write(hs, data, length);
         } else {
             goto fail;
         }
@@ -425,19 +424,18 @@ static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
         if (hs->kind != HID_KEYBOARD && hs->kind != HID_MOUSE) {
             goto fail;
         }
-        ret = 1;
         data[0] = hs->protocol;
+        p->actual_length = 1;
         break;
     case SET_PROTOCOL:
         if (hs->kind != HID_KEYBOARD && hs->kind != HID_MOUSE) {
             goto fail;
         }
-        ret = 0;
         hs->protocol = value;
         break;
     case GET_IDLE:
-        ret = 1;
         data[0] = hs->idle;
+        p->actual_length = 1;
         break;
     case SET_IDLE:
         hs->idle = (uint8_t) (value >> 8);
@@ -445,22 +443,20 @@ static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
         if (hs->kind == HID_MOUSE || hs->kind == HID_TABLET) {
             hid_pointer_activate(hs);
         }
-        ret = 0;
         break;
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_hid_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_hid_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBHIDState *us = DO_UPCAST(USBHIDState, dev, dev);
     HIDState *hs = &us->hid;
     uint8_t buf[p->iov.size];
-    int ret = 0;
+    int len = 0;
 
     switch (p->pid) {
     case USB_TOKEN_IN:
@@ -471,15 +467,16 @@ static int usb_hid_handle_data(USBDevice *dev, USBPacket *p)
             }
             if (!hid_has_events(hs) &&
                 (!hs->idle || hs->next_idle_clock - curtime > 0)) {
-                return USB_RET_NAK;
+                p->status = USB_RET_NAK;
+                return;
             }
             hid_set_next_idle(hs, curtime);
             if (hs->kind == HID_MOUSE || hs->kind == HID_TABLET) {
-                ret = hid_pointer_poll(hs, buf, p->iov.size);
+                len = hid_pointer_poll(hs, buf, p->iov.size);
             } else if (hs->kind == HID_KEYBOARD) {
-                ret = hid_keyboard_poll(hs, buf, p->iov.size);
+                len = hid_keyboard_poll(hs, buf, p->iov.size);
             }
-            usb_packet_copy(p, buf, ret);
+            usb_packet_copy(p, buf, len);
         } else {
             goto fail;
         }
@@ -487,10 +484,9 @@ static int usb_hid_handle_data(USBDevice *dev, USBPacket *p)
     case USB_TOKEN_OUT:
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_hid_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/dev-hub.c b/hw/usb/dev-hub.c
index 8fd30df..9ee60dd 100644
--- a/hw/usb/dev-hub.c
+++ b/hw/usb/dev-hub.c
@@ -288,7 +288,7 @@ static const char *feature_name(int feature)
     return name[feature] ?: "?";
 }
 
-static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_hub_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBHubState *s = (USBHubState *)dev;
@@ -298,7 +298,7 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
     switch(request) {
@@ -306,7 +306,6 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
         if (value == 0 && index != 0x81) { /* clear ep halt */
             goto fail;
         }
-        ret = 0;
         break;
         /* usb specific requests */
     case GetHubStatus:
@@ -314,7 +313,7 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
         data[1] = 0;
         data[2] = 0;
         data[3] = 0;
-        ret = 4;
+        p->actual_length = 4;
         break;
     case GetPortStatus:
         {
@@ -331,16 +330,14 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
             data[1] = port->wPortStatus >> 8;
             data[2] = port->wPortChange;
             data[3] = port->wPortChange >> 8;
-            ret = 4;
+            p->actual_length = 4;
         }
         break;
     case SetHubFeature:
     case ClearHubFeature:
-        if (value == 0 || value == 1) {
-        } else {
+        if (value != 0 && value != 1) {
             goto fail;
         }
-        ret = 0;
         break;
     case SetPortFeature:
         {
@@ -373,7 +370,6 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
             default:
                 goto fail;
             }
-            ret = 0;
         }
         break;
     case ClearPortFeature:
@@ -413,7 +409,6 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
             default:
                 goto fail;
             }
-            ret = 0;
         }
         break;
     case GetHubDescriptor:
@@ -437,22 +432,20 @@ static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
                 var_hub_size++;
             }
 
-            ret = sizeof(qemu_hub_hub_descriptor) + var_hub_size;
-            data[0] = ret;
+            p->actual_length = sizeof(qemu_hub_hub_descriptor) + var_hub_size;
+            data[0] = p->actual_length;
             break;
         }
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_hub_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_hub_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBHubState *s = (USBHubState *)dev;
-    int ret;
 
     switch(p->pid) {
     case USB_TOKEN_IN:
@@ -465,7 +458,8 @@ static int usb_hub_handle_data(USBDevice *dev, USBPacket *p)
             if (p->iov.size == 1) { /* FreeBSD workaround */
                 n = 1;
             } else if (n > p->iov.size) {
-                return USB_RET_BABBLE;
+                p->status = USB_RET_BABBLE;
+                return;
             }
             status = 0;
             for(i = 0; i < NUM_PORTS; i++) {
@@ -478,9 +472,8 @@ static int usb_hub_handle_data(USBDevice *dev, USBPacket *p)
                     buf[i] = status >> (8 * i);
                 }
                 usb_packet_copy(p, buf, n);
-                ret = n;
             } else {
-                ret = USB_RET_NAK; /* usb11 11.13.1 */
+                p->status = USB_RET_NAK; /* usb11 11.13.1 */
             }
         } else {
             goto fail;
@@ -489,10 +482,9 @@ static int usb_hub_handle_data(USBDevice *dev, USBPacket *p)
     case USB_TOKEN_OUT:
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_hub_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/dev-network.c b/hw/usb/dev-network.c
index e4a4359..14d9e5a 100644
--- a/hw/usb/dev-network.c
+++ b/hw/usb/dev-network.c
@@ -1048,7 +1048,7 @@ static void usb_net_handle_reset(USBDevice *dev)
 {
 }
 
-static int usb_net_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_net_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBNetState *s = (USBNetState *) dev;
@@ -1056,10 +1056,9 @@ static int usb_net_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch(request) {
     case ClassInterfaceOutRequest | USB_CDC_SEND_ENCAPSULATED_COMMAND:
         if (!is_rndis(s) || value || index != 0) {
@@ -1078,22 +1077,25 @@ static int usb_net_handle_control(USBDevice *dev, USBPacket *p,
         }
 #endif
         ret = rndis_parse(s, data, length);
+        if (ret < 0) {
+            p->status = ret;
+        }
         break;
 
     case ClassInterfaceRequest | USB_CDC_GET_ENCAPSULATED_RESPONSE:
         if (!is_rndis(s) || value || index != 0) {
             goto fail;
         }
-        ret = rndis_get_response(s, data);
-        if (!ret) {
+        p->actual_length = rndis_get_response(s, data);
+        if (p->actual_length == 0) {
             data[0] = 0;
-            ret = 1;
+            p->actual_length = 1;
         }
 #ifdef TRAFFIC_DEBUG
         {
             unsigned int i;
             fprintf(stderr, "GET_ENCAPSULATED_RESPONSE:");
-            for (i = 0; i < ret; i++) {
+            for (i = 0; i < p->actual_length; i++) {
                 if (!(i & 15))
                     fprintf(stderr, "\n%04x:", i);
                 fprintf(stderr, " %02x", data[i]);
@@ -1108,72 +1110,67 @@ static int usb_net_handle_control(USBDevice *dev, USBPacket *p,
         fprintf(stderr, "usbnet: failed control transaction: "
                         "request 0x%x value 0x%x index 0x%x length 0x%x\n",
                         request, value, index, length);
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_net_handle_statusin(USBNetState *s, USBPacket *p)
+static void usb_net_handle_statusin(USBNetState *s, USBPacket *p)
 {
     le32 buf[2];
-    int ret = 8;
 
     if (p->iov.size < 8) {
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
 
     buf[0] = cpu_to_le32(1);
     buf[1] = cpu_to_le32(0);
     usb_packet_copy(p, buf, 8);
-    if (!s->rndis_resp.tqh_first)
-        ret = USB_RET_NAK;
+    if (!s->rndis_resp.tqh_first) {
+        p->status = USB_RET_NAK;
+    }
 
 #ifdef TRAFFIC_DEBUG
     fprintf(stderr, "usbnet: interrupt poll len %zu return %d",
-            p->iov.size, ret);
-    iov_hexdump(p->iov.iov, p->iov.niov, stderr, "usbnet", ret);
+            p->iov.size, p->status);
+    iov_hexdump(p->iov.iov, p->iov.niov, stderr, "usbnet", p->status);
 #endif
-
-    return ret;
 }
 
-static int usb_net_handle_datain(USBNetState *s, USBPacket *p)
+static void usb_net_handle_datain(USBNetState *s, USBPacket *p)
 {
-    int ret = USB_RET_NAK;
+    int len;
 
     if (s->in_ptr > s->in_len) {
         usb_net_reset_in_buf(s);
-        ret = USB_RET_NAK;
-        return ret;
+        p->status = USB_RET_NAK;
+        return;
     }
     if (!s->in_len) {
-        ret = USB_RET_NAK;
-        return ret;
+        p->status = USB_RET_NAK;
+        return;
     }
-    ret = s->in_len - s->in_ptr;
-    if (ret > p->iov.size) {
-        ret = p->iov.size;
+    len = s->in_len - s->in_ptr;
+    if (len > p->iov.size) {
+        len = p->iov.size;
     }
-    usb_packet_copy(p, &s->in_buf[s->in_ptr], ret);
-    s->in_ptr += ret;
+    usb_packet_copy(p, &s->in_buf[s->in_ptr], len);
+    s->in_ptr += len;
     if (s->in_ptr >= s->in_len &&
-                    (is_rndis(s) || (s->in_len & (64 - 1)) || !ret)) {
+                    (is_rndis(s) || (s->in_len & (64 - 1)) || !len)) {
         /* no short packet necessary */
         usb_net_reset_in_buf(s);
     }
 
 #ifdef TRAFFIC_DEBUG
-    fprintf(stderr, "usbnet: data in len %zu return %d", p->iov.size, ret);
-    iov_hexdump(p->iov.iov, p->iov.niov, stderr, "usbnet", ret);
+    fprintf(stderr, "usbnet: data in len %zu return %d", p->iov.size, len);
+    iov_hexdump(p->iov.iov, p->iov.niov, stderr, "usbnet", len);
 #endif
-
-    return ret;
 }
 
-static int usb_net_handle_dataout(USBNetState *s, USBPacket *p)
+static void usb_net_handle_dataout(USBNetState *s, USBPacket *p)
 {
-    int ret = p->iov.size;
     int sz = sizeof(s->out_buf) - s->out_ptr;
     struct rndis_packet_msg_type *msg =
             (struct rndis_packet_msg_type *) s->out_buf;
@@ -1184,21 +1181,23 @@ static int usb_net_handle_dataout(USBNetState *s, USBPacket *p)
     iov_hexdump(p->iov.iov, p->iov.niov, stderr, "usbnet", p->iov.size);
 #endif
 
-    if (sz > ret)
-        sz = ret;
+    if (sz > p->iov.size) {
+        sz = p->iov.size;
+    }
     usb_packet_copy(p, &s->out_buf[s->out_ptr], sz);
     s->out_ptr += sz;
 
     if (!is_rndis(s)) {
-        if (ret < 64) {
+        if (p->iov.size < 64) {
             qemu_send_packet(&s->nic->nc, s->out_buf, s->out_ptr);
             s->out_ptr = 0;
         }
-        return ret;
+        return;
     }
     len = le32_to_cpu(msg->MessageLength);
-    if (s->out_ptr < 8 || s->out_ptr < len)
-        return ret;
+    if (s->out_ptr < 8 || s->out_ptr < len) {
+        return;
+    }
     if (le32_to_cpu(msg->MessageType) == RNDIS_PACKET_MSG) {
         uint32_t offs = 8 + le32_to_cpu(msg->DataOffset);
         uint32_t size = le32_to_cpu(msg->DataLength);
@@ -1207,24 +1206,21 @@ static int usb_net_handle_dataout(USBNetState *s, USBPacket *p)
     }
     s->out_ptr -= len;
     memmove(s->out_buf, &s->out_buf[len], s->out_ptr);
-
-    return ret;
 }
 
-static int usb_net_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_net_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBNetState *s = (USBNetState *) dev;
-    int ret = 0;
 
     switch(p->pid) {
     case USB_TOKEN_IN:
         switch (p->ep->nr) {
         case 1:
-            ret = usb_net_handle_statusin(s, p);
+            usb_net_handle_statusin(s, p);
             break;
 
         case 2:
-            ret = usb_net_handle_datain(s, p);
+            usb_net_handle_datain(s, p);
             break;
 
         default:
@@ -1235,7 +1231,7 @@ static int usb_net_handle_data(USBDevice *dev, USBPacket *p)
     case USB_TOKEN_OUT:
         switch (p->ep->nr) {
         case 2:
-            ret = usb_net_handle_dataout(s, p);
+            usb_net_handle_dataout(s, p);
             break;
 
         default:
@@ -1245,14 +1241,15 @@ static int usb_net_handle_data(USBDevice *dev, USBPacket *p)
 
     default:
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    if (ret == USB_RET_STALL)
+
+    if (p->status == USB_RET_STALL) {
         fprintf(stderr, "usbnet: failed data transaction: "
                         "pid 0x%x ep 0x%x len 0x%zx\n",
                         p->pid, p->ep->nr, p->iov.size);
-    return ret;
+    }
 }
 
 static ssize_t usbnet_receive(NetClientState *nc, const uint8_t *buf, size_t size)
diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
index a466f99..99b19df 100644
--- a/hw/usb/dev-serial.c
+++ b/hw/usb/dev-serial.c
@@ -219,7 +219,7 @@ static uint8_t usb_get_modem_lines(USBSerialState *s)
     return ret;
 }
 
-static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_serial_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBSerialState *s = (USBSerialState *)dev;
@@ -228,13 +228,11 @@ static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
     DPRINTF("got control %x, value %x\n",request, value);
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
-        ret = 0;
         break;
 
         /* Class specific requests.  */
@@ -323,7 +321,7 @@ static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
     case DeviceInVendor | FTDI_GET_MDM_ST:
         data[0] = usb_get_modem_lines(s) | 1;
         data[1] = 0;
-        ret = 2;
+        p->actual_length = 2;
         break;
     case DeviceOutVendor | FTDI_SET_EVENT_CHR:
         /* TODO: handle it */
@@ -338,25 +336,23 @@ static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
         break;
     case DeviceInVendor | FTDI_GET_LATENCY:
         data[0] = s->latency;
-        ret = 1;
+        p->actual_length = 1;
         break;
     default:
     fail:
         DPRINTF("got unsupported/bogus control %x, value %x\n", request, value);
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_serial_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBSerialState *s = (USBSerialState *)dev;
-    int i, ret = 0;
     uint8_t devep = p->ep->nr;
     struct iovec *iov;
     uint8_t header[2];
-    int first_len, len;
+    int i, first_len, len;
 
     switch (p->pid) {
     case USB_TOKEN_OUT:
@@ -366,6 +362,7 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
             iov = p->iov.iov + i;
             qemu_chr_fe_write(s->cs, iov->iov_base, iov->iov_len);
         }
+        p->actual_length = p->iov.size;
         break;
 
     case USB_TOKEN_IN:
@@ -374,7 +371,7 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
         first_len = RECV_BUF - s->recv_ptr;
         len = p->iov.size;
         if (len <= 2) {
-            ret = USB_RET_NAK;
+            p->status = USB_RET_NAK;
             break;
         }
         header[0] = usb_get_modem_lines(s) | 1;
@@ -384,7 +381,6 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
             s->event_trigger &= ~FTDI_BI;
             header[1] = FTDI_BI;
             usb_packet_copy(p, header, 2);
-            ret = 2;
             break;
         } else {
             header[1] = 0;
@@ -393,7 +389,7 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
         if (len > s->recv_used)
             len = s->recv_used;
         if (!len) {
-            ret = USB_RET_NAK;
+            p->status = USB_RET_NAK;
             break;
         }
         if (first_len > len)
@@ -404,17 +400,14 @@ static int usb_serial_handle_data(USBDevice *dev, USBPacket *p)
             usb_packet_copy(p, s->recv_buf, len - first_len);
         s->recv_used -= len;
         s->recv_ptr = (s->recv_ptr + len) % RECV_BUF;
-        ret = len + 2;
         break;
 
     default:
         DPRINTF("Bad token\n");
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void usb_serial_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 1ea0791..190fcd6 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -635,39 +635,38 @@ static void ccid_handle_reset(USBDevice *dev)
     ccid_reset(s);
 }
 
-static int ccid_handle_control(USBDevice *dev, USBPacket *p, int request,
+static void ccid_handle_control(USBDevice *dev, USBPacket *p, int request,
                                int value, int index, int length, uint8_t *data)
 {
     USBCCIDState *s = DO_UPCAST(USBCCIDState, dev, dev);
-    int ret = 0;
+    int ret;
 
     DPRINTF(s, 1, "got control %x, value %x\n", request, value);
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
     switch (request) {
         /* Class specific requests.  */
     case InterfaceOutClass | CCID_CONTROL_ABORT:
         DPRINTF(s, 1, "ccid_control abort UNIMPLEMENTED\n");
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     case InterfaceInClass | CCID_CONTROL_GET_CLOCK_FREQUENCIES:
         DPRINTF(s, 1, "ccid_control get clock frequencies UNIMPLEMENTED\n");
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     case InterfaceInClass | CCID_CONTROL_GET_DATA_RATES:
         DPRINTF(s, 1, "ccid_control get data rates UNIMPLEMENTED\n");
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     default:
         DPRINTF(s, 1, "got unsupported/bogus control %x, value %x\n",
                 request, value);
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static bool ccid_card_inserted(USBCCIDState *s)
@@ -870,18 +869,13 @@ static void ccid_on_apdu_from_guest(USBCCIDState *s, CCID_XferBlock *recv)
     }
 }
 
-/*
- * Handle a single USB_TOKEN_OUT, return value returned to guest.
- * Return value:
- *  0             - all ok
- *  USB_RET_STALL - failed to handle packet
- */
-static int ccid_handle_bulk_out(USBCCIDState *s, USBPacket *p)
+static void ccid_handle_bulk_out(USBCCIDState *s, USBPacket *p)
 {
     CCID_Header *ccid_header;
 
     if (p->iov.size + s->bulk_out_pos > BULK_OUT_DATA_SIZE) {
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
     ccid_header = (CCID_Header *)s->bulk_out_data;
     usb_packet_copy(p, s->bulk_out_data + s->bulk_out_pos, p->iov.size);
@@ -890,7 +884,7 @@ static int ccid_handle_bulk_out(USBCCIDState *s, USBPacket *p)
         DPRINTF(s, D_VERBOSE,
             "usb-ccid: bulk_in: expecting more packets (%zd/%d)\n",
             p->iov.size, ccid_header->dwLength);
-        return 0;
+        return;
     }
     if (s->bulk_out_pos < 10) {
         DPRINTF(s, 1,
@@ -949,60 +943,52 @@ static int ccid_handle_bulk_out(USBCCIDState *s, USBPacket *p)
         }
     }
     s->bulk_out_pos = 0;
-    return 0;
 }
 
-static int ccid_bulk_in_copy_to_guest(USBCCIDState *s, USBPacket *p)
+static void ccid_bulk_in_copy_to_guest(USBCCIDState *s, USBPacket *p)
 {
-    int ret = 0;
+    int len = 0;
 
-    assert(p->iov.size > 0);
     ccid_bulk_in_get(s);
     if (s->current_bulk_in != NULL) {
-        ret = MIN(s->current_bulk_in->len - s->current_bulk_in->pos,
+        len = MIN(s->current_bulk_in->len - s->current_bulk_in->pos,
                   p->iov.size);
         usb_packet_copy(p, s->current_bulk_in->data +
-                        s->current_bulk_in->pos, ret);
-        s->current_bulk_in->pos += ret;
+                        s->current_bulk_in->pos, len);
+        s->current_bulk_in->pos += len;
         if (s->current_bulk_in->pos == s->current_bulk_in->len) {
             ccid_bulk_in_release(s);
         }
     } else {
         /* return when device has no data - usb 2.0 spec Table 8-4 */
-        ret = USB_RET_NAK;
+        p->status = USB_RET_NAK;
     }
-    if (ret > 0) {
+    if (len) {
         DPRINTF(s, D_MORE_INFO,
                 "%s: %zd/%d req/act to guest (BULK_IN)\n",
-                __func__, p->iov.size, ret);
+                __func__, p->iov.size, len);
     }
-    if (ret != USB_RET_NAK && ret < p->iov.size) {
+    if (len < p->iov.size) {
         DPRINTF(s, 1,
                 "%s: returning short (EREMOTEIO) %d < %zd\n",
-                __func__, ret, p->iov.size);
+                __func__, len, p->iov.size);
     }
-    return ret;
 }
 
-static int ccid_handle_data(USBDevice *dev, USBPacket *p)
+static void ccid_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBCCIDState *s = DO_UPCAST(USBCCIDState, dev, dev);
-    int ret = 0;
     uint8_t buf[2];
 
     switch (p->pid) {
     case USB_TOKEN_OUT:
-        ret = ccid_handle_bulk_out(s, p);
+        ccid_handle_bulk_out(s, p);
         break;
 
     case USB_TOKEN_IN:
         switch (p->ep->nr) {
         case CCID_BULK_IN_EP:
-            if (!p->iov.size) {
-                ret = USB_RET_NAK;
-            } else {
-                ret = ccid_bulk_in_copy_to_guest(s, p);
-            }
+            ccid_bulk_in_copy_to_guest(s, p);
             break;
         case CCID_INT_IN_EP:
             if (s->notify_slot_change) {
@@ -1010,7 +996,6 @@ static int ccid_handle_data(USBDevice *dev, USBPacket *p)
                 buf[0] = CCID_MESSAGE_TYPE_RDR_to_PC_NotifySlotChange;
                 buf[1] = s->bmSlotICCState;
                 usb_packet_copy(p, buf, 2);
-                ret = 2;
                 s->notify_slot_change = false;
                 s->bmSlotICCState &= ~SLOT_0_CHANGED_MASK;
                 DPRINTF(s, D_INFO,
@@ -1021,17 +1006,15 @@ static int ccid_handle_data(USBDevice *dev, USBPacket *p)
             break;
         default:
             DPRINTF(s, 1, "Bad endpoint\n");
-            ret = USB_RET_STALL;
+            p->status = USB_RET_STALL;
             break;
         }
         break;
     default:
         DPRINTF(s, 1, "Bad token\n");
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void ccid_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
index e732191..50af971 100644
--- a/hw/usb/dev-storage.c
+++ b/hw/usb/dev-storage.c
@@ -215,7 +215,7 @@ static const USBDesc desc = {
 static void usb_msd_copy_data(MSDState *s, USBPacket *p)
 {
     uint32_t len;
-    len = p->iov.size - p->result;
+    len = p->iov.size - p->actual_length;
     if (len > s->scsi_len)
         len = s->scsi_len;
     usb_packet_copy(p, scsi_req_get_buf(s->req) + s->scsi_off, len);
@@ -263,7 +263,8 @@ static void usb_msd_transfer_data(SCSIRequest *req, uint32_t len)
     if (p) {
         usb_msd_copy_data(s, p);
         p = s->packet;
-        if (p && p->result == p->iov.size) {
+        if (p && p->actual_length == p->iov.size) {
+            p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
             usb_msd_packet_complete(s);
         }
     }
@@ -292,7 +293,7 @@ static void usb_msd_command_complete(SCSIRequest *req, uint32_t status, size_t r
             s->mode = USB_MSDM_CBW;
         } else {
             if (s->data_len) {
-                int len = (p->iov.size - p->result);
+                int len = (p->iov.size - p->actual_length);
                 usb_packet_skip(p, len);
                 s->data_len -= len;
             }
@@ -300,6 +301,7 @@ static void usb_msd_command_complete(SCSIRequest *req, uint32_t status, size_t r
                 s->mode = USB_MSDM_CSW;
             }
         }
+        p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
         usb_msd_packet_complete(s);
     } else if (s->data_len == 0) {
         s->mode = USB_MSDM_CSW;
@@ -330,14 +332,14 @@ static void usb_msd_handle_reset(USBDevice *dev)
     assert(s->req == NULL);
 
     if (s->packet) {
-        s->packet->result = USB_RET_STALL;
+        s->packet->status = USB_RET_STALL;
         usb_msd_packet_complete(s);
     }
 
     s->mode = USB_MSDM_CBW;
 }
 
-static int usb_msd_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_msd_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     MSDState *s = (MSDState *)dev;
@@ -345,29 +347,25 @@ static int usb_msd_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
-        ret = 0;
         break;
         /* Class specific requests.  */
     case ClassInterfaceOutRequest | MassStorageReset:
         /* Reset state ready for the next CBW.  */
         s->mode = USB_MSDM_CBW;
-        ret = 0;
         break;
     case ClassInterfaceRequest | GetMaxLun:
         data[0] = 0;
-        ret = 1;
+        p->actual_length = 1;
         break;
     default:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_msd_cancel_io(USBDevice *dev, USBPacket *p)
@@ -382,11 +380,10 @@ static void usb_msd_cancel_io(USBDevice *dev, USBPacket *p)
     }
 }
 
-static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_msd_handle_data(USBDevice *dev, USBPacket *p)
 {
     MSDState *s = (MSDState *)dev;
     uint32_t tag;
-    int ret = 0;
     struct usb_msd_cbw cbw;
     uint8_t devep = p->ep->nr;
 
@@ -433,7 +430,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             if (s->req && s->req->cmd.xfer != SCSI_XFER_NONE) {
                 scsi_req_continue(s->req);
             }
-            ret = p->result;
             break;
 
         case USB_MSDM_DATAOUT:
@@ -446,7 +442,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                 usb_msd_copy_data(s, p);
             }
             if (le32_to_cpu(s->csw.residue)) {
-                int len = p->iov.size - p->result;
+                int len = p->iov.size - p->actual_length;
                 if (len) {
                     usb_packet_skip(p, len);
                     s->data_len -= len;
@@ -455,12 +451,10 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                     }
                 }
             }
-            if (p->result < p->iov.size) {
+            if (p->actual_length < p->iov.size) {
                 DPRINTF("Deferring packet %p [wait data-out]\n", p);
                 s->packet = p;
-                ret = USB_RET_ASYNC;
-            } else {
-                ret = p->result;
+                p->status = USB_RET_ASYNC;
             }
             break;
 
@@ -481,7 +475,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             }
             /* Waiting for SCSI write to complete.  */
             s->packet = p;
-            ret = USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
             break;
 
         case USB_MSDM_CSW:
@@ -493,11 +487,10 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                 /* still in flight */
                 DPRINTF("Deferring packet %p [wait status]\n", p);
                 s->packet = p;
-                ret = USB_RET_ASYNC;
+                p->status = USB_RET_ASYNC;
             } else {
                 usb_msd_send_status(s, p);
                 s->mode = USB_MSDM_CBW;
-                ret = 13;
             }
             break;
 
@@ -508,7 +501,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                 usb_msd_copy_data(s, p);
             }
             if (le32_to_cpu(s->csw.residue)) {
-                int len = p->iov.size - p->result;
+                int len = p->iov.size - p->actual_length;
                 if (len) {
                     usb_packet_skip(p, len);
                     s->data_len -= len;
@@ -517,12 +510,10 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                     }
                 }
             }
-            if (p->result < p->iov.size) {
+            if (p->actual_length < p->iov.size) {
                 DPRINTF("Deferring packet %p [wait data-in]\n", p);
                 s->packet = p;
-                ret = USB_RET_ASYNC;
-            } else {
-                ret = p->result;
+                p->status = USB_RET_ASYNC;
             }
             break;
 
@@ -535,11 +526,9 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
     default:
         DPRINTF("Bad token\n");
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void usb_msd_password_cb(void *opaque, int err)
diff --git a/hw/usb/dev-uas.c b/hw/usb/dev-uas.c
index 4389380..a21b2ba 100644
--- a/hw/usb/dev-uas.c
+++ b/hw/usb/dev-uas.c
@@ -256,10 +256,10 @@ static void usb_uas_send_status_bh(void *opaque)
 
     uas->status = NULL;
     usb_packet_copy(p, &st->status, st->length);
-    p->result = st->length;
     QTAILQ_REMOVE(&uas->results, st, next);
     g_free(st);
 
+    p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
     usb_packet_complete(&uas->dev, p);
 }
 
@@ -349,6 +349,7 @@ static void usb_uas_complete_data_packet(UASRequest *req)
     p = req->data;
     req->data = NULL;
     req->data_async = false;
+    p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
     usb_packet_complete(&req->uas->dev, p);
 }
 
@@ -357,16 +358,16 @@ static void usb_uas_copy_data(UASRequest *req)
     uint32_t length;
 
     length = MIN(req->buf_size - req->buf_off,
-                 req->data->iov.size - req->data->result);
+                 req->data->iov.size - req->data->actual_length);
     trace_usb_uas_xfer_data(req->uas->dev.addr, req->tag, length,
-                            req->data->result, req->data->iov.size,
+                            req->data->actual_length, req->data->iov.size,
                             req->buf_off, req->buf_size);
     usb_packet_copy(req->data, scsi_req_get_buf(req->req) + req->buf_off,
                     length);
     req->buf_off += length;
     req->data_off += length;
 
-    if (req->data->result == req->data->iov.size) {
+    if (req->data->actual_length == req->data->iov.size) {
         usb_uas_complete_data_packet(req);
     }
     if (req->buf_size && req->buf_off == req->buf_size) {
@@ -504,17 +505,17 @@ static void usb_uas_handle_reset(USBDevice *dev)
     }
 }
 
-static int usb_uas_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_uas_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     int ret;
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
     fprintf(stderr, "%s: unhandled control request\n", __func__);
-    return USB_RET_STALL;
+    p->status = USB_RET_STALL;
 }
 
 static void usb_uas_cancel_io(USBDevice *dev, USBPacket *p)
@@ -641,13 +642,13 @@ incorrect_lun:
     usb_uas_queue_response(uas, tag, UAS_RC_INCORRECT_LUN, 0);
 }
 
-static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_uas_handle_data(USBDevice *dev, USBPacket *p)
 {
     UASDevice *uas = DO_UPCAST(UASDevice, dev, dev);
     uas_ui ui;
     UASStatus *st;
     UASRequest *req;
-    int length, ret = 0;
+    int length;
 
     switch (p->ep->nr) {
     case UAS_PIPE_ID_COMMAND:
@@ -656,16 +657,14 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
         switch (ui.hdr.id) {
         case UAS_UI_COMMAND:
             usb_uas_command(uas, &ui);
-            ret = length;
             break;
         case UAS_UI_TASK_MGMT:
             usb_uas_task(uas, &ui);
-            ret = length;
             break;
         default:
             fprintf(stderr, "%s: unknown command ui: id 0x%x\n",
                     __func__, ui.hdr.id);
-            ret = USB_RET_STALL;
+            p->status = USB_RET_STALL;
             break;
         }
         break;
@@ -674,11 +673,10 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
         if (st == NULL) {
             assert(uas->status == NULL);
             uas->status = p;
-            ret = USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
             break;
         }
         usb_packet_copy(p, &st->status, st->length);
-        ret = st->length;
         QTAILQ_REMOVE(&uas->results, st, next);
         g_free(st);
         break;
@@ -687,28 +685,26 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
         req = (p->ep->nr == UAS_PIPE_ID_DATA_IN) ? uas->datain : uas->dataout;
         if (req == NULL) {
             fprintf(stderr, "%s: no inflight request\n", __func__);
-            ret = USB_RET_STALL;
+            p->status = USB_RET_STALL;
             break;
         }
         scsi_req_ref(req->req);
         req->data = p;
         usb_uas_copy_data(req);
-        if (p->result == p->iov.size || req->complete) {
+        if (p->actual_length == p->iov.size || req->complete) {
             req->data = NULL;
-            ret = p->result;
         } else {
             req->data_async = true;
-            ret = USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
         }
         scsi_req_unref(req->req);
         usb_uas_start_next_transfer(uas);
         break;
     default:
         fprintf(stderr, "%s: invalid endpoint %d\n", __func__, p->ep->nr);
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_uas_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/dev-wacom.c b/hw/usb/dev-wacom.c
index ed9a5ee..08b416d 100644
--- a/hw/usb/dev-wacom.c
+++ b/hw/usb/dev-wacom.c
@@ -250,7 +250,7 @@ static void usb_wacom_handle_reset(USBDevice *dev)
     s->mode = WACOM_MODE_HID;
 }
 
-static int usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBWacomState *s = (USBWacomState *) dev;
@@ -258,10 +258,9 @@ static int usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case WACOM_SET_REPORT:
         if (s->mouse_grabbed) {
@@ -269,61 +268,58 @@ static int usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
             s->mouse_grabbed = 0;
         }
         s->mode = data[0];
-        ret = 0;
         break;
     case WACOM_GET_REPORT:
         data[0] = 0;
         data[1] = s->mode;
-        ret = 2;
+        p->actual_length = 2;
         break;
     /* USB HID requests */
     case HID_GET_REPORT:
         if (s->mode == WACOM_MODE_HID)
-            ret = usb_mouse_poll(s, data, length);
+            p->actual_length = usb_mouse_poll(s, data, length);
         else if (s->mode == WACOM_MODE_WACOM)
-            ret = usb_wacom_poll(s, data, length);
+            p->actual_length = usb_wacom_poll(s, data, length);
         break;
     case HID_GET_IDLE:
-        ret = 1;
         data[0] = s->idle;
+        p->actual_length = 1;
         break;
     case HID_SET_IDLE:
         s->idle = (uint8_t) (value >> 8);
-        ret = 0;
         break;
     default:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
-static int usb_wacom_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_wacom_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBWacomState *s = (USBWacomState *) dev;
     uint8_t buf[p->iov.size];
-    int ret = 0;
+    int len = 0;
 
     switch (p->pid) {
     case USB_TOKEN_IN:
         if (p->ep->nr == 1) {
-            if (!(s->changed || s->idle))
-                return USB_RET_NAK;
+            if (!(s->changed || s->idle)) {
+                p->status = USB_RET_NAK;
+                return;
+            }
             s->changed = 0;
             if (s->mode == WACOM_MODE_HID)
-                ret = usb_mouse_poll(s, buf, p->iov.size);
+                len = usb_mouse_poll(s, buf, p->iov.size);
             else if (s->mode == WACOM_MODE_WACOM)
-                ret = usb_wacom_poll(s, buf, p->iov.size);
-            usb_packet_copy(p, buf, ret);
+                len = usb_wacom_poll(s, buf, p->iov.size);
+            usb_packet_copy(p, buf, len);
             break;
         }
         /* Fall through.  */
     case USB_TOKEN_OUT:
     default:
-        ret = USB_RET_STALL;
-        break;
+        p->status = USB_RET_STALL;
     }
-    return ret;
 }
 
 static void usb_wacom_handle_destroy(USBDevice *dev)
diff --git a/hw/usb/hcd-ehci-pci.c b/hw/usb/hcd-ehci-pci.c
index d5c7d46..fe45a1f 100644
--- a/hw/usb/hcd-ehci-pci.c
+++ b/hw/usb/hcd-ehci-pci.c
@@ -91,6 +91,7 @@ static const VMStateDescription vmstate_ehci_pci = {
     .fields      = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(pcidev, EHCIPCIState),
         VMSTATE_STRUCT(ehci, EHCIPCIState, 2, vmstate_ehci, EHCIState),
+        VMSTATE_END_OF_LIST()
     }
 };
 
@@ -105,7 +106,7 @@ static void ehci_class_init(ObjectClass *klass, void *data)
     k->device_id = i->device_id;
     k->revision = i->revision;
     k->class_id = PCI_CLASS_SERIAL_USB;
-    dc->vmsd = &vmstate_ehci;
+    dc->vmsd = &vmstate_ehci_pci;
     dc->props = ehci_pci_properties;
 }
 
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index d9dc576..ee6c9ae 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -29,9 +29,6 @@
 
 #include "hw/usb/hcd-ehci.h"
 
-/* internal processing - reset HC to try and recover */
-#define USB_RET_PROCERR   (-99)
-
 /* Capability Registers Base Address - section 2.2 */
 #define CAPLENGTH        0x0000  /* 1-byte, 0x0001 reserved */
 #define HCIVERSION       0x0002  /* 2-bytes, i/f version # */
@@ -1111,7 +1108,7 @@ static int ehci_init_transfer(EHCIPacket *p)
     while (bytes > 0) {
         if (cpage > 4) {
             fprintf(stderr, "cpage out of range (%d)\n", cpage);
-            return USB_RET_PROCERR;
+            return -1;
         }
 
         page  = p->qtd.bufptr[cpage] & QTD_BUFPTR_MASK;
@@ -1129,16 +1126,16 @@ static int ehci_init_transfer(EHCIPacket *p)
     return 0;
 }
 
-static void ehci_finish_transfer(EHCIQueue *q, int status)
+static void ehci_finish_transfer(EHCIQueue *q, int len)
 {
     uint32_t cpage, offset;
 
-    if (status > 0) {
+    if (len > 0) {
         /* update cpage & offset */
         cpage  = get_field(q->qh.token, QTD_TOKEN_CPAGE);
         offset = q->qh.bufptr[0] & ~QTD_BUFPTR_MASK;
 
-        offset += status;
+        offset += len;
         cpage  += offset >> QTD_BUFPTR_SH;
         offset &= ~QTD_BUFPTR_MASK;
 
@@ -1163,7 +1160,7 @@ 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 +1168,6 @@ 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;
 
     if (p->queue->async) {
         qemu_bh_schedule(p->queue->ehci->async_bh);
@@ -1181,58 +1177,60 @@ static void ehci_async_complete_packet(USBPort *port, USBPacket *packet)
 static void ehci_execute_complete(EHCIQueue *q)
 {
     EHCIPacket *p = QTAILQ_FIRST(&q->packets);
+    uint32_t tbytes;
 
     assert(p != NULL);
     assert(p->qtdaddr == q->qtdaddr);
     assert(p->async == EHCI_ASYNC_INITIALIZED ||
            p->async == EHCI_ASYNC_FINISHED);
 
-    DPRINTF("execute_complete: qhaddr 0x%x, next %x, qtdaddr 0x%x, status %d\n",
-            q->qhaddr, q->qh.next, q->qtdaddr, q->usb_status);
+    DPRINTF("execute_complete: qhaddr 0x%x, next 0x%x, qtdaddr 0x%x, "
+            "status %d, actual_length %d\n",
+            q->qhaddr, q->qh.next, q->qtdaddr,
+            p->packet.status, p->packet.actual_length);
 
-    if (p->usb_status < 0) {
-        switch (p->usb_status) {
-        case USB_RET_IOERROR:
-        case USB_RET_NODEV:
-            q->qh.token |= (QTD_TOKEN_HALT | QTD_TOKEN_XACTERR);
-            set_field(&q->qh.token, 0, QTD_TOKEN_CERR);
-            ehci_raise_irq(q->ehci, USBSTS_ERRINT);
-            break;
-        case USB_RET_STALL:
-            q->qh.token |= QTD_TOKEN_HALT;
-            ehci_raise_irq(q->ehci, USBSTS_ERRINT);
-            break;
-        case USB_RET_NAK:
-            set_field(&q->qh.altnext_qtd, 0, QH_ALTNEXT_NAKCNT);
-            return; /* We're not done yet with this transaction */
-        case USB_RET_BABBLE:
-            q->qh.token |= (QTD_TOKEN_HALT | QTD_TOKEN_BABBLE);
-            ehci_raise_irq(q->ehci, USBSTS_ERRINT);
-            break;
-        default:
-            /* should not be triggerable */
-            fprintf(stderr, "USB invalid response %d\n", p->usb_status);
-            assert(0);
-            break;
+    switch (p->packet.status) {
+    case USB_RET_SUCCESS:
+        break;
+    case USB_RET_IOERROR:
+    case USB_RET_NODEV:
+        q->qh.token |= (QTD_TOKEN_HALT | QTD_TOKEN_XACTERR);
+        set_field(&q->qh.token, 0, QTD_TOKEN_CERR);
+        ehci_raise_irq(q->ehci, USBSTS_ERRINT);
+        break;
+    case USB_RET_STALL:
+        q->qh.token |= QTD_TOKEN_HALT;
+        ehci_raise_irq(q->ehci, USBSTS_ERRINT);
+        break;
+    case USB_RET_NAK:
+        set_field(&q->qh.altnext_qtd, 0, QH_ALTNEXT_NAKCNT);
+        return; /* We're not done yet with this transaction */
+    case USB_RET_BABBLE:
+        q->qh.token |= (QTD_TOKEN_HALT | QTD_TOKEN_BABBLE);
+        ehci_raise_irq(q->ehci, USBSTS_ERRINT);
+        break;
+    default:
+        /* should not be triggerable */
+        fprintf(stderr, "USB invalid response %d\n", p->packet.status);
+        assert(0);
+        break;
+    }
+
+    /* TODO check 4.12 for splits */
+    tbytes = get_field(q->qh.token, QTD_TOKEN_TBYTES);
+    if (tbytes && p->pid == USB_TOKEN_IN) {
+        tbytes -= p->packet.actual_length;
+        if (tbytes) {
+            /* 4.15.1.2 must raise int on a short input packet */
+            ehci_raise_irq(q->ehci, USBSTS_INT);
         }
     } else {
-        // TODO check 4.12 for splits
-        uint32_t tbytes = get_field(q->qh.token, QTD_TOKEN_TBYTES);
-
-        if (tbytes && p->pid == USB_TOKEN_IN) {
-            tbytes -= p->usb_status;
-            if (tbytes) {
-                /* 4.15.1.2 must raise int on a short input packet */
-                ehci_raise_irq(q->ehci, USBSTS_INT);
-            }
-        } else {
-            tbytes = 0;
-        }
-
-        DPRINTF("updating tbytes to %d\n", tbytes);
-        set_field(&q->qh.token, tbytes, QTD_TOKEN_TBYTES);
+        tbytes = 0;
     }
-    ehci_finish_transfer(q, p->usb_status);
+    DPRINTF("updating tbytes to %d\n", tbytes);
+    set_field(&q->qh.token, tbytes, QTD_TOKEN_TBYTES);
+
+    ehci_finish_transfer(q, p->packet.actual_length);
     usb_packet_unmap(&p->packet, &p->sgl);
     qemu_sglist_destroy(&p->sgl);
     p->async = EHCI_ASYNC_NONE;
@@ -1248,12 +1246,10 @@ static void ehci_execute_complete(EHCIQueue *q)
     }
 }
 
-// 4.10.3
-
+/* 4.10.3 returns "again" */
 static int ehci_execute(EHCIPacket *p, const char *action)
 {
     USBEndpoint *ep;
-    int ret;
     int endp;
     bool spd;
 
@@ -1262,13 +1258,13 @@ static int ehci_execute(EHCIPacket *p, const char *action)
 
     if (!(p->qtd.token & QTD_TOKEN_ACTIVE)) {
         fprintf(stderr, "Attempting to execute inactive qtd\n");
-        return USB_RET_PROCERR;
+        return -1;
     }
 
     if (get_field(p->qtd.token, QTD_TOKEN_TBYTES) > BUFF_SIZE) {
         ehci_trace_guest_bug(p->queue->ehci,
                              "guest requested more bytes than allowed");
-        return USB_RET_PROCERR;
+        return -1;
     }
 
     p->pid = (p->qtd.token & QTD_TOKEN_PID_MASK) >> QTD_TOKEN_PID_SH;
@@ -1292,7 +1288,7 @@ static int ehci_execute(EHCIPacket *p, const char *action)
 
     if (p->async == EHCI_ASYNC_NONE) {
         if (ehci_init_transfer(p) != 0) {
-            return USB_RET_PROCERR;
+            return -1;
         }
 
         spd = (p->pid == USB_TOKEN_IN && NLPTR_TBIT(p->qtd.altnext) == 0);
@@ -1303,17 +1299,18 @@ 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 -1;
     }
 
-    return ret;
+    return 1;
 }
 
 /*  4.7.2
@@ -1325,7 +1322,6 @@ static int ehci_process_itd(EHCIState *ehci,
 {
     USBDevice *dev;
     USBEndpoint *ep;
-    int ret;
     uint32_t i, len, pid, dir, devaddr, endp;
     uint32_t pg, off, ptr1, ptr2, max, mult;
 
@@ -1348,7 +1344,7 @@ static int ehci_process_itd(EHCIState *ehci,
             }
 
             if (len > BUFF_SIZE) {
-                return USB_RET_PROCERR;
+                return -1;
             }
 
             qemu_sglist_init(&ehci->isgl, 2, ehci->dma);
@@ -1370,45 +1366,45 @@ 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);
             } else {
                 DPRINTF("ISOCH: attempt to addess non-iso endpoint\n");
-                ret = USB_RET_NAK;
+                ehci->ipacket.status = USB_RET_NAK;
+                ehci->ipacket.actual_length = 0;
             }
             qemu_sglist_destroy(&ehci->isgl);
 
-            if (ret < 0) {
-                switch (ret) {
-                default:
-                    fprintf(stderr, "Unexpected iso usb result: %d\n", ret);
-                    /* Fall through */
-                case USB_RET_IOERROR:
-                case USB_RET_NODEV:
-                    /* 3.3.2: XACTERR is only allowed on IN transactions */
-                    if (dir) {
-                        itd->transact[i] |= ITD_XACT_XACTERR;
-                        ehci_raise_irq(ehci, USBSTS_ERRINT);
-                    }
-                    break;
-                case USB_RET_BABBLE:
-                    itd->transact[i] |= ITD_XACT_BABBLE;
+            switch (ehci->ipacket.status) {
+            case USB_RET_SUCCESS:
+                break;
+            default:
+                fprintf(stderr, "Unexpected iso usb result: %d\n",
+                        ehci->ipacket.status);
+                /* Fall through */
+            case USB_RET_IOERROR:
+            case USB_RET_NODEV:
+                /* 3.3.2: XACTERR is only allowed on IN transactions */
+                if (dir) {
+                    itd->transact[i] |= ITD_XACT_XACTERR;
                     ehci_raise_irq(ehci, USBSTS_ERRINT);
-                    break;
-                case USB_RET_NAK:
-                    /* no data for us, so do a zero-length transfer */
-                    ret = 0;
-                    break;
                 }
+                break;
+            case USB_RET_BABBLE:
+                itd->transact[i] |= ITD_XACT_BABBLE;
+                ehci_raise_irq(ehci, USBSTS_ERRINT);
+                break;
+            case USB_RET_NAK:
+                /* no data for us, so do a zero-length transfer */
+                ehci->ipacket.actual_length = 0;
+                break;
             }
-            if (ret >= 0) {
-                if (!dir) {
-                    /* OUT */
-                    set_field(&itd->transact[i], len - ret, ITD_XACT_LENGTH);
-                } else {
-                    /* IN */
-                    set_field(&itd->transact[i], ret, ITD_XACT_LENGTH);
-                }
+            if (!dir) {
+                set_field(&itd->transact[i], len - ehci->ipacket.actual_length,
+                          ITD_XACT_LENGTH); /* OUT */
+            } else {
+                set_field(&itd->transact[i], ehci->ipacket.actual_length,
+                          ITD_XACT_LENGTH); /* IN */
             }
             if (itd->transact[i] & ITD_XACT_IOC) {
                 ehci_raise_irq(ehci, USBSTS_INT);
@@ -1746,8 +1742,7 @@ static int ehci_state_fetchqtd(EHCIQueue *q)
             break;
         case EHCI_ASYNC_INFLIGHT:
             /* Check if the guest has added new tds to the queue */
-            again = (ehci_fill_queue(QTAILQ_LAST(&q->packets, pkts_head)) ==
-                     USB_RET_PROCERR) ? -1 : 1;
+            again = ehci_fill_queue(QTAILQ_LAST(&q->packets, pkts_head));
             /* Unfinished async handled packet, go horizontal */
             ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
             break;
@@ -1784,6 +1779,7 @@ static int ehci_state_horizqh(EHCIQueue *q)
     return again;
 }
 
+/* Returns "again" */
 static int ehci_fill_queue(EHCIPacket *p)
 {
     USBEndpoint *ep = p->packet.ep;
@@ -1812,17 +1808,14 @@ static int ehci_fill_queue(EHCIPacket *p)
         p = ehci_alloc_packet(q);
         p->qtdaddr = qtdaddr;
         p->qtd = qtd;
-        p->usb_status = ehci_execute(p, "queue");
-        if (p->usb_status == USB_RET_PROCERR) {
-            break;
+        if (ehci_execute(p, "queue") == -1) {
+            return -1;
         }
-        assert(p->usb_status == USB_RET_ASYNC);
+        assert(p->packet.status == USB_RET_ASYNC);
         p->async = EHCI_ASYNC_INFLIGHT;
     }
-    if (p->usb_status != USB_RET_PROCERR) {
-        usb_device_flush_ep_queue(ep->dev, ep);
-    }
-    return p->usb_status;
+    usb_device_flush_ep_queue(ep->dev, ep);
+    return 1;
 }
 
 static int ehci_state_execute(EHCIQueue *q)
@@ -1851,18 +1844,17 @@ static int ehci_state_execute(EHCIQueue *q)
         ehci_set_usbsts(q->ehci, USBSTS_REC);
     }
 
-    p->usb_status = ehci_execute(p, "process");
-    if (p->usb_status == USB_RET_PROCERR) {
-        again = -1;
+    again = ehci_execute(p, "process");
+    if (again == -1) {
         goto out;
     }
-    if (p->usb_status == USB_RET_ASYNC) {
+    if (p->packet.status == USB_RET_ASYNC) {
         ehci_flush_qh(q);
         trace_usb_ehci_packet_action(p->queue, p, "async");
         p->async = EHCI_ASYNC_INFLIGHT;
         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
         if (q->async) {
-            again = (ehci_fill_queue(p) == USB_RET_PROCERR) ? -1 : 1;
+            again = ehci_fill_queue(p);
         } else {
             again = 1;
         }
@@ -1891,7 +1883,7 @@ static int ehci_state_executing(EHCIQueue *q)
     }
 
     /* 4.10.5 */
-    if (p->usb_status == USB_RET_NAK) {
+    if (p->packet.status == USB_RET_NAK) {
         ehci_set_state(q->ehci, q->async, EST_HORIZONTALQH);
     } else {
         ehci_set_state(q->ehci, q->async, EST_WRITEBACK);
diff --git a/hw/usb/hcd-ehci.h b/hw/usb/hcd-ehci.h
index 0ec675c..d8078f4 100644
--- a/hw/usb/hcd-ehci.h
+++ b/hw/usb/hcd-ehci.h
@@ -230,7 +230,6 @@ struct EHCIPacket {
     QEMUSGList sgl;
     int pid;
     enum async_state async;
-    int usb_status;
 };
 
 struct EHCIQueue {
diff --git a/hw/usb/hcd-musb.c b/hw/usb/hcd-musb.c
index 4f55390..c707f7a 100644
--- a/hw/usb/hcd-musb.c
+++ b/hw/usb/hcd-musb.c
@@ -607,7 +607,6 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep,
 {
     USBDevice *dev;
     USBEndpoint *uep;
-    int ret;
     int idx = epnum && dir;
     int ttype;
 
@@ -632,15 +631,19 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep,
     ep->packey[dir].ep = ep;
     ep->packey[dir].dir = dir;
 
-    ret = usb_handle_packet(dev, &ep->packey[dir].p);
+    usb_handle_packet(dev, &ep->packey[dir].p);
 
-    if (ret == USB_RET_ASYNC) {
+    if (ep->packey[dir].p.status == USB_RET_ASYNC) {
         usb_device_flush_ep_queue(dev, uep);
         ep->status[dir] = len;
         return;
     }
 
-    ep->status[dir] = ret;
+    if (ep->packey[dir].p.status == USB_RET_SUCCESS) {
+        ep->status[dir] = ep->packey[dir].p.actual_length;
+    } else {
+        ep->status[dir] = ep->packey[dir].p.status;
+    }
     musb_schedule_cb(&s->port, &ep->packey[dir].p);
 }
 
@@ -754,7 +757,6 @@ static void musb_rx_packet_complete(USBPacket *packey, void *opaque)
 
     if (ep->status[1] == USB_RET_STALL) {
         ep->status[1] = 0;
-        packey->result = 0;
 
         ep->csr[1] |= MGC_M_RXCSR_H_RXSTALL;
         if (!epnum)
@@ -793,14 +795,12 @@ static void musb_rx_packet_complete(USBPacket *packey, void *opaque)
     /* TODO: check len for over/underruns of an OUT packet?  */
     /* TODO: perhaps make use of e->ext_size[1] here.  */
 
-    packey->result = ep->status[1];
-
     if (!(ep->csr[1] & (MGC_M_RXCSR_H_RXSTALL | MGC_M_RXCSR_DATAERROR))) {
         ep->csr[1] |= MGC_M_RXCSR_FIFOFULL | MGC_M_RXCSR_RXPKTRDY;
         if (!epnum)
             ep->csr[0] |= MGC_M_CSR0_RXPKTRDY;
 
-        ep->rxcount = packey->result; /* XXX: MIN(packey->len, ep->maxp[1]); */
+        ep->rxcount = ep->status[1]; /* XXX: MIN(packey->len, ep->maxp[1]); */
         /* In DMA mode: assert DMA request for this EP */
     }
 
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 7571e9e..6a39e96 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -807,21 +807,24 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed,
                          DMA_DIRECTION_TO_DEVICE);
     }
 
-    if (completion) {
-        ret = ohci->usb_packet.result;
-    } else {
+    if (!completion) {
         bool int_req = relative_frame_number == frame_count &&
                        OHCI_BM(iso_td.flags, TD_DI) == 0;
         dev = ohci_find_device(ohci, OHCI_BM(ed->flags, ED_FA));
         ep = usb_ep_get(dev, pid, OHCI_BM(ed->flags, ED_EN));
         usb_packet_setup(&ohci->usb_packet, pid, ep, addr, false, int_req);
         usb_packet_addbuf(&ohci->usb_packet, ohci->usb_buf, len);
-        ret = usb_handle_packet(dev, &ohci->usb_packet);
-        if (ret == USB_RET_ASYNC) {
+        usb_handle_packet(dev, &ohci->usb_packet);
+        if (ohci->usb_packet.status == USB_RET_ASYNC) {
             usb_device_flush_ep_queue(dev, ep);
             return 1;
         }
     }
+    if (ohci->usb_packet.status == USB_RET_SUCCESS) {
+        ret = ohci->usb_packet.actual_length;
+    } else {
+        ret = ohci->usb_packet.status;
+    }
 
 #ifdef DEBUG_ISOCH
     printf("so 0x%.8x eo 0x%.8x\nsa 0x%.8x ea 0x%.8x\ndir %s len %zu ret %d\n",
@@ -997,7 +1000,6 @@ static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed)
     }
 #endif
     if (completion) {
-        ret = ohci->usb_packet.result;
         ohci->async_td = 0;
         ohci->async_complete = 0;
     } else {
@@ -1017,16 +1019,22 @@ static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed)
         usb_packet_setup(&ohci->usb_packet, pid, ep, addr, !flag_r,
                          OHCI_BM(td.flags, TD_DI) == 0);
         usb_packet_addbuf(&ohci->usb_packet, ohci->usb_buf, pktlen);
-        ret = usb_handle_packet(dev, &ohci->usb_packet);
+        usb_handle_packet(dev, &ohci->usb_packet);
 #ifdef DEBUG_PACKET
-        DPRINTF("ret=%d\n", ret);
+        DPRINTF("status=%d\n", ohci->usb_packet.status);
 #endif
-        if (ret == USB_RET_ASYNC) {
+        if (ohci->usb_packet.status == USB_RET_ASYNC) {
             usb_device_flush_ep_queue(dev, ep);
             ohci->async_td = addr;
             return 1;
         }
     }
+    if (ohci->usb_packet.status == USB_RET_SUCCESS) {
+        ret = ohci->usb_packet.actual_length;
+    } else {
+        ret = ohci->usb_packet.status;
+    }
+
     if (ret >= 0) {
         if (dir == OHCI_TD_DIR_IN) {
             ohci_copy_td(ohci, &td, ohci->usb_buf, ret,
diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index f4b555a..2838d21 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -780,22 +780,21 @@ static int uhci_handle_td_error(UHCIState *s, UHCI_TD *td, uint32_t td_addr,
 
 static int uhci_complete_td(UHCIState *s, UHCI_TD *td, UHCIAsync *async, uint32_t *int_mask)
 {
-    int len = 0, max_len, ret;
+    int len = 0, max_len;
     uint8_t pid;
 
     max_len = ((td->token >> 21) + 1) & 0x7ff;
     pid = td->token & 0xff;
 
-    ret = async->packet.result;
-
     if (td->ctrl & TD_CTRL_IOS)
         td->ctrl &= ~TD_CTRL_ACTIVE;
 
-    if (ret < 0) {
-        return uhci_handle_td_error(s, td, async->td_addr, ret, int_mask);
+    if (async->packet.status != USB_RET_SUCCESS) {
+        return uhci_handle_td_error(s, td, async->td_addr,
+                                    async->packet.status, int_mask);
     }
 
-    len = async->packet.result;
+    len = async->packet.actual_length;
     td->ctrl = (td->ctrl & ~0x7ff) | ((len - 1) & 0x7ff);
 
     /* The NAK bit may have been set by a previous frame, so clear it
@@ -824,7 +823,7 @@ static int uhci_complete_td(UHCIState *s, UHCI_TD *td, UHCIAsync *async, uint32_
 static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
                           UHCI_TD *td, uint32_t td_addr, uint32_t *int_mask)
 {
-    int len = 0, max_len;
+    int ret, max_len;
     bool spd;
     bool queuing = (q != NULL);
     uint8_t pid = td->token & 0xff;
@@ -915,13 +914,14 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
     switch(pid) {
     case USB_TOKEN_OUT:
     case USB_TOKEN_SETUP:
-        len = usb_handle_packet(q->ep->dev, &async->packet);
-        if (len >= 0)
-            len = max_len;
+        usb_handle_packet(q->ep->dev, &async->packet);
+        if (async->packet.status == USB_RET_SUCCESS) {
+            async->packet.actual_length = max_len;
+        }
         break;
 
     case USB_TOKEN_IN:
-        len = usb_handle_packet(q->ep->dev, &async->packet);
+        usb_handle_packet(q->ep->dev, &async->packet);
         break;
 
     default:
@@ -932,8 +932,8 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
         uhci_update_irq(s);
         return TD_RESULT_STOP_FRAME;
     }
- 
-    if (len == USB_RET_ASYNC) {
+
+    if (async->packet.status == USB_RET_ASYNC) {
         uhci_async_link(async);
         if (!queuing) {
             uhci_queue_fill(q, td);
@@ -941,13 +941,11 @@ static int uhci_handle_td(UHCIState *s, UHCIQueue *q, uint32_t qh_addr,
         return TD_RESULT_ASYNC_START;
     }
 
-    async->packet.result = len;
-
 done:
-    len = uhci_complete_td(s, td, async, int_mask);
+    ret = uhci_complete_td(s, td, async, int_mask);
     usb_packet_unmap(&async->packet, &async->sgl);
     uhci_async_free(async);
-    return len;
+    return ret;
 }
 
 static void uhci_async_complete(USBPort *port, USBPacket *packet)
@@ -955,7 +953,7 @@ static void uhci_async_complete(USBPort *port, USBPacket *packet)
     UHCIAsync *async = container_of(packet, UHCIAsync, packet);
     UHCIState *s = async->queue->uhci;
 
-    if (packet->result == USB_RET_REMOVE_FROM_QUEUE) {
+    if (packet->status == USB_RET_REMOVE_FROM_QUEUE) {
         uhci_async_unlink(async);
         uhci_async_cancel(async);
         return;
diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 900abf5..8ef4b07 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -634,6 +634,34 @@ static inline dma_addr_t xhci_mask64(uint64_t addr)
     }
 }
 
+static inline void xhci_dma_read_u32s(XHCIState *xhci, dma_addr_t addr,
+                                      uint32_t *buf, size_t len)
+{
+    int i;
+
+    assert((len % sizeof(uint32_t)) == 0);
+
+    pci_dma_read(&xhci->pci_dev, addr, buf, len);
+
+    for (i = 0; i < (len / sizeof(uint32_t)); i++) {
+        buf[i] = le32_to_cpu(buf[i]);
+    }
+}
+
+static inline void xhci_dma_write_u32s(XHCIState *xhci, dma_addr_t addr,
+                                       uint32_t *buf, size_t len)
+{
+    int i;
+    uint32_t tmp[len / sizeof(uint32_t)];
+
+    assert((len % sizeof(uint32_t)) == 0);
+
+    for (i = 0; i < (len / sizeof(uint32_t)); i++) {
+        tmp[i] = cpu_to_le32(buf[i]);
+    }
+    pci_dma_write(&xhci->pci_dev, addr, tmp, len);
+}
+
 static XHCIPort *xhci_lookup_port(XHCIState *xhci, struct USBPort *uport)
 {
     int index;
@@ -1045,14 +1073,14 @@ static void xhci_set_ep_state(XHCIState *xhci, XHCIEPContext *epctx,
 {
     uint32_t ctx[5];
 
-    pci_dma_read(&xhci->pci_dev, epctx->pctx, ctx, sizeof(ctx));
+    xhci_dma_read_u32s(xhci, epctx->pctx, ctx, sizeof(ctx));
     ctx[0] &= ~EP_STATE_MASK;
     ctx[0] |= state;
     ctx[2] = epctx->ring.dequeue | epctx->ring.ccs;
     ctx[3] = (epctx->ring.dequeue >> 16) >> 16;
     DPRINTF("xhci: set epctx: " DMA_ADDR_FMT " state=%d dequeue=%08x%08x\n",
             epctx->pctx, state, ctx[3], ctx[2]);
-    pci_dma_write(&xhci->pci_dev, epctx->pctx, ctx, sizeof(ctx));
+    xhci_dma_write_u32s(xhci, epctx->pctx, ctx, sizeof(ctx));
     epctx->state = state;
 }
 
@@ -1388,7 +1416,7 @@ static void xhci_xfer_report(XHCITransfer *xfer)
     XHCIState *xhci = xfer->xhci;
     int i;
 
-    left = xfer->packet.result < 0 ? 0 : xfer->packet.result;
+    left = xfer->packet.actual_length;
 
     for (i = 0; i < xfer->trb_count; i++) {
         XHCITRB *trb = &xfer->trbs[i];
@@ -1416,7 +1444,7 @@ static void xhci_xfer_report(XHCITransfer *xfer)
 
         if (!reported && ((trb->control & TRB_TR_IOC) ||
                           (shortpkt && (trb->control & TRB_TR_ISP)) ||
-                          (xfer->status != CC_SUCCESS))) {
+                          (xfer->status != CC_SUCCESS && left == 0))) {
             event.slotid = xfer->slotid;
             event.epid = xfer->epid;
             event.length = (trb->status & 0x1ffff) - chunk;
@@ -1490,16 +1518,16 @@ static int xhci_setup_packet(XHCITransfer *xfer)
     return 0;
 }
 
-static int xhci_complete_packet(XHCITransfer *xfer, int ret)
+static int xhci_complete_packet(XHCITransfer *xfer)
 {
-    if (ret == USB_RET_ASYNC) {
+    if (xfer->packet.status == USB_RET_ASYNC) {
         trace_usb_xhci_xfer_async(xfer);
         xfer->running_async = 1;
         xfer->running_retry = 0;
         xfer->complete = 0;
         xfer->cancelled = 0;
         return 0;
-    } else if (ret == USB_RET_NAK) {
+    } else if (xfer->packet.status == USB_RET_NAK) {
         trace_usb_xhci_xfer_nak(xfer);
         xfer->running_async = 0;
         xfer->running_retry = 1;
@@ -1513,16 +1541,16 @@ static int xhci_complete_packet(XHCITransfer *xfer, int ret)
         xhci_xfer_unmap(xfer);
     }
 
-    if (ret >= 0) {
-        trace_usb_xhci_xfer_success(xfer, ret);
+    if (xfer->packet.status == USB_RET_SUCCESS) {
+        trace_usb_xhci_xfer_success(xfer, xfer->packet.actual_length);
         xfer->status = CC_SUCCESS;
         xhci_xfer_report(xfer);
         return 0;
     }
 
     /* error */
-    trace_usb_xhci_xfer_error(xfer, ret);
-    switch (ret) {
+    trace_usb_xhci_xfer_error(xfer, xfer->packet.status);
+    switch (xfer->packet.status) {
     case USB_RET_NODEV:
         xfer->status = CC_USB_TRANSACTION_ERROR;
         xhci_xfer_report(xfer);
@@ -1534,7 +1562,8 @@ static int xhci_complete_packet(XHCITransfer *xfer, int ret)
         xhci_stall_ep(xfer);
         break;
     default:
-        fprintf(stderr, "%s: FIXME: ret = %d\n", __FUNCTION__, ret);
+        fprintf(stderr, "%s: FIXME: status = %d\n", __func__,
+                xfer->packet.status);
         FIXME();
     }
     return 0;
@@ -1544,7 +1573,6 @@ static int xhci_fire_ctl_transfer(XHCIState *xhci, XHCITransfer *xfer)
 {
     XHCITRB *trb_setup, *trb_status;
     uint8_t bmRequestType;
-    int ret;
 
     trb_setup = &xfer->trbs[0];
     trb_status = &xfer->trbs[xfer->trb_count-1];
@@ -1587,9 +1615,9 @@ static int xhci_fire_ctl_transfer(XHCIState *xhci, XHCITransfer *xfer)
     }
     xfer->packet.parameter = trb_setup->parameter;
 
-    ret = usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
+    usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
 
-    xhci_complete_packet(xfer, ret);
+    xhci_complete_packet(xfer);
     if (!xfer->running_async && !xfer->running_retry) {
         xhci_kick_ep(xhci, xfer->slotid, xfer->epid);
     }
@@ -1636,7 +1664,6 @@ static void xhci_check_iso_kick(XHCIState *xhci, XHCITransfer *xfer,
 static int xhci_submit(XHCIState *xhci, XHCITransfer *xfer, XHCIEPContext *epctx)
 {
     uint64_t mfindex;
-    int ret;
 
     DPRINTF("xhci_submit(slotid=%d,epid=%d)\n", xfer->slotid, xfer->epid);
 
@@ -1671,9 +1698,9 @@ static int xhci_submit(XHCIState *xhci, XHCITransfer *xfer, XHCIEPContext *epctx
     if (xhci_setup_packet(xfer) < 0) {
         return -1;
     }
-    ret = usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
+    usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
 
-    xhci_complete_packet(xfer, ret);
+    xhci_complete_packet(xfer);
     if (!xfer->running_async && !xfer->running_retry) {
         xhci_kick_ep(xhci, xfer->slotid, xfer->epid);
     }
@@ -1711,7 +1738,6 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid, unsigned int epid
 
     if (epctx->retry) {
         XHCITransfer *xfer = epctx->retry;
-        int result;
 
         trace_usb_xhci_xfer_retry(xfer);
         assert(xfer->running_retry);
@@ -1725,19 +1751,19 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid, unsigned int epid
             if (xhci_setup_packet(xfer) < 0) {
                 return;
             }
-            result = usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
-            assert(result != USB_RET_NAK);
-            xhci_complete_packet(xfer, result);
+            usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
+            assert(xfer->packet.status != USB_RET_NAK);
+            xhci_complete_packet(xfer);
         } else {
             /* retry nak'ed transfer */
             if (xhci_setup_packet(xfer) < 0) {
                 return;
             }
-            result = usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
-            if (result == USB_RET_NAK) {
+            usb_handle_packet(xfer->packet.ep->dev, &xfer->packet);
+            if (xfer->packet.status == USB_RET_NAK) {
                 return;
             }
-            xhci_complete_packet(xfer, result);
+            xhci_complete_packet(xfer);
         }
         assert(!xfer->running_retry);
         epctx->retry = NULL;
@@ -1883,14 +1909,14 @@ static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
     assert(slotid >= 1 && slotid <= xhci->numslots);
 
     dcbaap = xhci_addr64(xhci->dcbaap_low, xhci->dcbaap_high);
-    pci_dma_read(&xhci->pci_dev, dcbaap + 8*slotid, &poctx, sizeof(poctx));
+    poctx = ldq_le_pci_dma(&xhci->pci_dev, dcbaap + 8*slotid);
     ictx = xhci_mask64(pictx);
-    octx = xhci_mask64(le64_to_cpu(poctx));
+    octx = xhci_mask64(poctx);
 
     DPRINTF("xhci: input context at "DMA_ADDR_FMT"\n", ictx);
     DPRINTF("xhci: output context at "DMA_ADDR_FMT"\n", octx);
 
-    pci_dma_read(&xhci->pci_dev, ictx, ictl_ctx, sizeof(ictl_ctx));
+    xhci_dma_read_u32s(xhci, ictx, ictl_ctx, sizeof(ictl_ctx));
 
     if (ictl_ctx[0] != 0x0 || ictl_ctx[1] != 0x3) {
         fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
@@ -1898,8 +1924,8 @@ static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
         return CC_TRB_ERROR;
     }
 
-    pci_dma_read(&xhci->pci_dev, ictx+32, slot_ctx, sizeof(slot_ctx));
-    pci_dma_read(&xhci->pci_dev, ictx+64, ep0_ctx, sizeof(ep0_ctx));
+    xhci_dma_read_u32s(xhci, ictx+32, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_read_u32s(xhci, ictx+64, ep0_ctx, sizeof(ep0_ctx));
 
     DPRINTF("xhci: input slot context: %08x %08x %08x %08x\n",
             slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
@@ -1953,8 +1979,8 @@ static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
     DPRINTF("xhci: output ep0 context: %08x %08x %08x %08x %08x\n",
             ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
 
-    pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
-    pci_dma_write(&xhci->pci_dev, octx+32, ep0_ctx, sizeof(ep0_ctx));
+    xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_write_u32s(xhci, octx+32, ep0_ctx, sizeof(ep0_ctx));
 
     return res;
 }
@@ -1987,17 +2013,17 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
             }
         }
 
-        pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
         slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
         slot_ctx[3] |= SLOT_ADDRESSED << SLOT_STATE_SHIFT;
         DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
                 slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
-        pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
         return CC_SUCCESS;
     }
 
-    pci_dma_read(&xhci->pci_dev, ictx, ictl_ctx, sizeof(ictl_ctx));
+    xhci_dma_read_u32s(xhci, ictx, ictl_ctx, sizeof(ictl_ctx));
 
     if ((ictl_ctx[0] & 0x3) != 0x0 || (ictl_ctx[1] & 0x3) != 0x1) {
         fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
@@ -2005,8 +2031,8 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
         return CC_TRB_ERROR;
     }
 
-    pci_dma_read(&xhci->pci_dev, ictx+32, islot_ctx, sizeof(islot_ctx));
-    pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_read_u32s(xhci, ictx+32, islot_ctx, sizeof(islot_ctx));
+    xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
     if (SLOT_STATE(slot_ctx[3]) < SLOT_ADDRESSED) {
         fprintf(stderr, "xhci: invalid slot state %08x\n", slot_ctx[3]);
@@ -2018,8 +2044,7 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
             xhci_disable_ep(xhci, slotid, i);
         }
         if (ictl_ctx[1] & (1<<i)) {
-            pci_dma_read(&xhci->pci_dev, ictx+32+(32*i), ep_ctx,
-                         sizeof(ep_ctx));
+            xhci_dma_read_u32s(xhci, ictx+32+(32*i), ep_ctx, sizeof(ep_ctx));
             DPRINTF("xhci: input ep%d.%d context: %08x %08x %08x %08x %08x\n",
                     i/2, i%2, ep_ctx[0], ep_ctx[1], ep_ctx[2],
                     ep_ctx[3], ep_ctx[4]);
@@ -2031,7 +2056,7 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
             DPRINTF("xhci: output ep%d.%d context: %08x %08x %08x %08x %08x\n",
                     i/2, i%2, ep_ctx[0], ep_ctx[1], ep_ctx[2],
                     ep_ctx[3], ep_ctx[4]);
-            pci_dma_write(&xhci->pci_dev, octx+(32*i), ep_ctx, sizeof(ep_ctx));
+            xhci_dma_write_u32s(xhci, octx+(32*i), ep_ctx, sizeof(ep_ctx));
         }
     }
 
@@ -2043,7 +2068,7 @@ static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
     DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
             slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
 
-    pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
     return CC_SUCCESS;
 }
@@ -2068,7 +2093,7 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
     DPRINTF("xhci: input context at "DMA_ADDR_FMT"\n", ictx);
     DPRINTF("xhci: output context at "DMA_ADDR_FMT"\n", octx);
 
-    pci_dma_read(&xhci->pci_dev, ictx, ictl_ctx, sizeof(ictl_ctx));
+    xhci_dma_read_u32s(xhci, ictx, ictl_ctx, sizeof(ictl_ctx));
 
     if (ictl_ctx[0] != 0x0 || ictl_ctx[1] & ~0x3) {
         fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
@@ -2077,12 +2102,12 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
     }
 
     if (ictl_ctx[1] & 0x1) {
-        pci_dma_read(&xhci->pci_dev, ictx+32, islot_ctx, sizeof(islot_ctx));
+        xhci_dma_read_u32s(xhci, ictx+32, islot_ctx, sizeof(islot_ctx));
 
         DPRINTF("xhci: input slot context: %08x %08x %08x %08x\n",
                 islot_ctx[0], islot_ctx[1], islot_ctx[2], islot_ctx[3]);
 
-        pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
         slot_ctx[1] &= ~0xFFFF; /* max exit latency */
         slot_ctx[1] |= islot_ctx[1] & 0xFFFF;
@@ -2092,17 +2117,17 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
         DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
                 slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
 
-        pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+        xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
     }
 
     if (ictl_ctx[1] & 0x2) {
-        pci_dma_read(&xhci->pci_dev, ictx+64, iep0_ctx, sizeof(iep0_ctx));
+        xhci_dma_read_u32s(xhci, ictx+64, iep0_ctx, sizeof(iep0_ctx));
 
         DPRINTF("xhci: input ep0 context: %08x %08x %08x %08x %08x\n",
                 iep0_ctx[0], iep0_ctx[1], iep0_ctx[2],
                 iep0_ctx[3], iep0_ctx[4]);
 
-        pci_dma_read(&xhci->pci_dev, octx+32, ep0_ctx, sizeof(ep0_ctx));
+        xhci_dma_read_u32s(xhci, octx+32, ep0_ctx, sizeof(ep0_ctx));
 
         ep0_ctx[1] &= ~0xFFFF0000; /* max packet size*/
         ep0_ctx[1] |= iep0_ctx[1] & 0xFFFF0000;
@@ -2110,7 +2135,7 @@ static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
         DPRINTF("xhci: output ep0 context: %08x %08x %08x %08x %08x\n",
                 ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
 
-        pci_dma_write(&xhci->pci_dev, octx+32, ep0_ctx, sizeof(ep0_ctx));
+        xhci_dma_write_u32s(xhci, octx+32, ep0_ctx, sizeof(ep0_ctx));
     }
 
     return CC_SUCCESS;
@@ -2135,12 +2160,12 @@ static TRBCCode xhci_reset_slot(XHCIState *xhci, unsigned int slotid)
         }
     }
 
-    pci_dma_read(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_read_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
     slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
     slot_ctx[3] |= SLOT_DEFAULT << SLOT_STATE_SHIFT;
     DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
             slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
-    pci_dma_write(&xhci->pci_dev, octx, slot_ctx, sizeof(slot_ctx));
+    xhci_dma_write_u32s(xhci, octx, slot_ctx, sizeof(slot_ctx));
 
     return CC_SUCCESS;
 }
@@ -2922,11 +2947,11 @@ static void xhci_complete(USBPort *port, USBPacket *packet)
 {
     XHCITransfer *xfer = container_of(packet, XHCITransfer, packet);
 
-    if (packet->result == USB_RET_REMOVE_FROM_QUEUE) {
+    if (packet->status == USB_RET_REMOVE_FROM_QUEUE) {
         xhci_ep_nuke_one_xfer(xfer);
         return;
     }
-    xhci_complete_packet(xfer, packet->result);
+    xhci_complete_packet(xfer);
     xhci_kick_ep(xfer->xhci, xfer->slotid, xfer->epid);
 }
 
diff --git a/hw/usb/host-bsd.c b/hw/usb/host-bsd.c
index ec26266..6473e8b 100644
--- a/hw/usb/host-bsd.c
+++ b/hw/usb/host-bsd.c
@@ -121,7 +121,7 @@ static void usb_host_handle_reset(USBDevice *dev)
  * -check device states against transfer requests
  *  and return appropriate response
  */
-static int usb_host_handle_control(USBDevice *dev,
+static void usb_host_handle_control(USBDevice *dev,
                                    USBPacket *p,
                                    int request,
                                    int value,
@@ -139,7 +139,6 @@ static int usb_host_handle_control(USBDevice *dev,
 
         /* specific SET_ADDRESS support */
         dev->addr = value;
-        return 0;
     } else if ((request >> 8) == UT_WRITE_DEVICE &&
                (request & 0xff) == UR_SET_CONFIG) {
 
@@ -151,10 +150,8 @@ static int usb_host_handle_control(USBDevice *dev,
             printf("handle_control: failed to set configuration - %s\n",
                    strerror(errno));
 #endif
-            return USB_RET_STALL;
+            p->status = USB_RET_STALL;
         }
-
-        return 0;
     } else if ((request >> 8) == UT_WRITE_INTERFACE &&
                (request & 0xff) == UR_SET_INTERFACE) {
 
@@ -168,10 +165,8 @@ static int usb_host_handle_control(USBDevice *dev,
             printf("handle_control: failed to set alternate interface - %s\n",
                    strerror(errno));
 #endif
-            return USB_RET_STALL;
+            p->status = USB_RET_STALL;
         }
-
-        return 0;
     } else {
         req.ucr_request.bmRequestType = request >> 8;
         req.ucr_request.bRequest = request & 0xff;
@@ -201,14 +196,14 @@ static int usb_host_handle_control(USBDevice *dev,
             printf("handle_control: error after request - %s\n",
                    strerror(errno));
 #endif
-            return USB_RET_NAK; // STALL
+            p->status = USB_RET_NAK; /* STALL */
         } else {
-            return req.ucr_actlen;
+            p->actual_length = req.ucr_actlen;
         }
     }
 }
 
-static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_host_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBHostDevice *s = (USBHostDevice *)dev;
     int ret, fd, mode;
@@ -232,7 +227,8 @@ static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
     fd = ensure_ep_open(s, devep, mode);
     if (fd < 0) {
         sigprocmask(SIG_SETMASK, &old_mask, NULL);
-        return USB_RET_NODEV;
+        p->status = USB_RET_NODEV;
+        return;
     }
 
     if (ioctl(fd, USB_SET_TIMEOUT, &timeout) < 0) {
@@ -267,12 +263,13 @@ static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
         switch(errno) {
         case ETIMEDOUT:
         case EINTR:
-            return USB_RET_NAK;
+            p->status = USB_RET_NAK;
+            break;
         default:
-            return USB_RET_STALL;
+            p->status = USB_RET_STALL;
         }
     } else {
-        return ret;
+        p->actual_length = ret;
     }
 }
 
diff --git a/hw/usb/host-linux.c b/hw/usb/host-linux.c
index 3a258b4..ca3e24a 100644
--- a/hw/usb/host-linux.c
+++ b/hw/usb/host-linux.c
@@ -366,28 +366,29 @@ static void async_complete(void *opaque)
         if (p) {
             switch (aurb->urb.status) {
             case 0:
-                p->result += aurb->urb.actual_length;
+                p->actual_length = aurb->urb.actual_length;
+                p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
                 break;
 
             case -EPIPE:
                 set_halt(s, p->pid, p->ep->nr);
-                p->result = USB_RET_STALL;
+                p->status = USB_RET_STALL;
                 break;
 
             case -EOVERFLOW:
-                p->result = USB_RET_BABBLE;
+                p->status = USB_RET_BABBLE;
                 break;
 
             default:
-                p->result = USB_RET_IOERROR;
+                p->status = USB_RET_IOERROR;
                 break;
             }
 
             if (aurb->urb.type == USBDEVFS_URB_TYPE_CONTROL) {
-                trace_usb_host_req_complete(s->bus_num, s->addr, p, p->result);
+                trace_usb_host_req_complete(s->bus_num, s->addr, p, p->status);
                 usb_generic_async_ctrl_complete(&s->dev, p);
             } else if (!aurb->more) {
-                trace_usb_host_req_complete(s->bus_num, s->addr, p, p->result);
+                trace_usb_host_req_complete(s->bus_num, s->addr, p, p->status);
                 usb_packet_complete(&s->dev, p);
             }
         }
@@ -733,27 +734,31 @@ static void usb_host_stop_n_free_iso(USBHostDevice *s, int pid, uint8_t ep)
     clear_iso_started(s, pid, ep);
 }
 
-static int urb_status_to_usb_ret(int status)
+static void urb_status_to_usb_ret(int status, USBPacket *p)
 {
     switch (status) {
     case -EPIPE:
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        break;
     case -EOVERFLOW:
-        return USB_RET_BABBLE;
+        p->status = USB_RET_BABBLE;
+        break;
     default:
-        return USB_RET_IOERROR;
+        p->status = USB_RET_IOERROR;
     }
 }
 
-static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
+static void usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
 {
     AsyncURB *aurb;
-    int i, j, ret, max_packet_size, offset, len = 0;
+    int i, j, max_packet_size, offset, len;
     uint8_t *buf;
 
     max_packet_size = p->ep->max_packet_size;
-    if (max_packet_size == 0)
-        return USB_RET_NAK;
+    if (max_packet_size == 0) {
+        p->status = USB_RET_NAK;
+        return;
+    }
 
     aurb = get_iso_urb(s, p->pid, p->ep->nr);
     if (!aurb) {
@@ -766,18 +771,17 @@ static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
         if (in) {
             /* Check urb status  */
             if (aurb[i].urb.status) {
-                len = urb_status_to_usb_ret(aurb[i].urb.status);
+                urb_status_to_usb_ret(aurb[i].urb.status, p);
                 /* Move to the next urb */
                 aurb[i].iso_frame_idx = ISO_FRAME_DESC_PER_URB - 1;
             /* Check frame status */
             } else if (aurb[i].urb.iso_frame_desc[j].status) {
-                len = urb_status_to_usb_ret(
-                                        aurb[i].urb.iso_frame_desc[j].status);
+                urb_status_to_usb_ret(aurb[i].urb.iso_frame_desc[j].status, p);
             /* Check the frame fits */
             } else if (aurb[i].urb.iso_frame_desc[j].actual_length
                        > p->iov.size) {
                 printf("husb: received iso data is larger then packet\n");
-                len = USB_RET_BABBLE;
+                p->status = USB_RET_BABBLE;
             /* All good copy data over */
             } else {
                 len = aurb[i].urb.iso_frame_desc[j].actual_length;
@@ -792,7 +796,8 @@ static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
             /* Check the frame fits */
             if (len > max_packet_size) {
                 printf("husb: send iso data is larger then max packet size\n");
-                return USB_RET_NAK;
+                p->status = USB_RET_NAK;
+                return;
             }
 
             /* All good copy data over */
@@ -823,17 +828,16 @@ static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
         /* (Re)-submit all fully consumed / filled urbs */
         for (i = 0; i < s->iso_urb_count; i++) {
             if (aurb[i].iso_frame_idx == ISO_FRAME_DESC_PER_URB) {
-                ret = ioctl(s->fd, USBDEVFS_SUBMITURB, &aurb[i]);
-                if (ret < 0) {
+                if (ioctl(s->fd, USBDEVFS_SUBMITURB, &aurb[i]) < 0) {
                     perror("USBDEVFS_SUBMITURB");
-                    if (!in || len == 0) {
+                    if (!in || p->status == USB_RET_SUCCESS) {
                         switch(errno) {
                         case ETIMEDOUT:
-                            len = USB_RET_NAK;
+                            p->status = USB_RET_NAK;
                             break;
                         case EPIPE:
                         default:
-                            len = USB_RET_STALL;
+                            p->status = USB_RET_STALL;
                         }
                     }
                     break;
@@ -843,11 +847,9 @@ static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p, int in)
             }
         }
     }
-
-    return len;
 }
 
-static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_host_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBHostDevice *s = DO_UPCAST(USBHostDevice, dev, dev);
     struct usbdevfs_urb *urb;
@@ -862,7 +864,8 @@ static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
 
     if (!is_valid(s, p->pid, p->ep->nr)) {
         trace_usb_host_req_complete(s->bus_num, s->addr, p, USB_RET_NAK);
-        return USB_RET_NAK;
+        p->status = USB_RET_NAK;
+        return;
     }
 
     if (p->pid == USB_TOKEN_IN) {
@@ -877,13 +880,15 @@ static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
         if (ret < 0) {
             perror("USBDEVFS_CLEAR_HALT");
             trace_usb_host_req_complete(s->bus_num, s->addr, p, USB_RET_NAK);
-            return USB_RET_NAK;
+            p->status = USB_RET_NAK;
+            return;
         }
         clear_halt(s, p->pid, p->ep->nr);
     }
 
     if (is_isoc(s, p->pid, p->ep->nr)) {
-        return usb_host_handle_iso_data(s, p, p->pid == USB_TOKEN_IN);
+        usb_host_handle_iso_data(s, p, p->pid == USB_TOKEN_IN);
+        return;
     }
 
     v = 0;
@@ -933,17 +938,19 @@ static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
             case ETIMEDOUT:
                 trace_usb_host_req_complete(s->bus_num, s->addr, p,
                                             USB_RET_NAK);
-                return USB_RET_NAK;
+                p->status = USB_RET_NAK;
+                break;
             case EPIPE:
             default:
                 trace_usb_host_req_complete(s->bus_num, s->addr, p,
                                             USB_RET_STALL);
-                return USB_RET_STALL;
+                p->status = USB_RET_STALL;
             }
+            return;
         }
     } while (rem > 0);
 
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
 static int ctrl_error(void)
@@ -955,14 +962,13 @@ static int ctrl_error(void)
     }
 }
 
-static int usb_host_set_address(USBHostDevice *s, int addr)
+static void usb_host_set_address(USBHostDevice *s, int addr)
 {
     trace_usb_host_set_address(s->bus_num, s->addr, addr);
     s->dev.addr = addr;
-    return 0;
 }
 
-static int usb_host_set_config(USBHostDevice *s, int config)
+static void usb_host_set_config(USBHostDevice *s, int config, USBPacket *p)
 {
     int ret, first = 1;
 
@@ -987,14 +993,15 @@ again:
     }
 
     if (ret < 0) {
-        return ctrl_error();
+        p->status = ctrl_error();
+        return;
     }
     usb_host_claim_interfaces(s, config);
     usb_linux_update_endp_table(s);
-    return 0;
 }
 
-static int usb_host_set_interface(USBHostDevice *s, int iface, int alt)
+static void usb_host_set_interface(USBHostDevice *s, int iface, int alt,
+                                   USBPacket *p)
 {
     struct usbdevfs_setinterface si;
     int i, ret;
@@ -1011,7 +1018,8 @@ static int usb_host_set_interface(USBHostDevice *s, int iface, int alt)
     }
 
     if (iface >= USB_MAX_INTERFACES) {
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
 
     si.interface  = iface;
@@ -1022,15 +1030,15 @@ static int usb_host_set_interface(USBHostDevice *s, int iface, int alt)
             iface, alt, ret, errno);
 
     if (ret < 0) {
-        return ctrl_error();
+        p->status = ctrl_error();
+        return;
     }
 
     s->dev.altsetting[iface] = alt;
     usb_linux_update_endp_table(s);
-    return 0;
 }
 
-static int usb_host_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_host_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     USBHostDevice *s = DO_UPCAST(USBHostDevice, dev, dev);
@@ -1048,19 +1056,19 @@ static int usb_host_handle_control(USBDevice *dev, USBPacket *p,
 
     switch (request) {
     case DeviceOutRequest | USB_REQ_SET_ADDRESS:
-        ret = usb_host_set_address(s, value);
-        trace_usb_host_req_emulated(s->bus_num, s->addr, p, ret);
-        return ret;
+        usb_host_set_address(s, value);
+        trace_usb_host_req_emulated(s->bus_num, s->addr, p, p->status);
+        return;
 
     case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
-        ret = usb_host_set_config(s, value & 0xff);
-        trace_usb_host_req_emulated(s->bus_num, s->addr, p, ret);
-        return ret;
+        usb_host_set_config(s, value & 0xff, p);
+        trace_usb_host_req_emulated(s->bus_num, s->addr, p, p->status);
+        return;
 
     case InterfaceOutRequest | USB_REQ_SET_INTERFACE:
-        ret = usb_host_set_interface(s, index, value);
-        trace_usb_host_req_emulated(s->bus_num, s->addr, p, ret);
-        return ret;
+        usb_host_set_interface(s, index, value, p);
+        trace_usb_host_req_emulated(s->bus_num, s->addr, p, p->status);
+        return;
 
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
         if (value == 0) { /* clear halt */
@@ -1068,17 +1076,16 @@ static int usb_host_handle_control(USBDevice *dev, USBPacket *p,
             ioctl(s->fd, USBDEVFS_CLEAR_HALT, &index);
             clear_halt(s, pid, index & 0x0f);
             trace_usb_host_req_emulated(s->bus_num, s->addr, p, 0);
-            return 0;
+            return;
         }
     }
 
     /* The rest are asynchronous */
-    assert(p && p->result == 0);
-
     if (length > sizeof(dev->data_buf)) {
         fprintf(stderr, "husb: ctrl buffer too small (%d > %zu)\n",
                 length, sizeof(dev->data_buf));
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        return;
     }
 
     aurb = async_alloc(s);
@@ -1112,14 +1119,17 @@ static int usb_host_handle_control(USBDevice *dev, USBPacket *p,
 
         switch(errno) {
         case ETIMEDOUT:
-            return USB_RET_NAK;
+            p->status = USB_RET_NAK;
+            break;
         case EPIPE:
         default:
-            return USB_RET_STALL;
+            p->status = USB_RET_STALL;
+            break;
         }
+        return;
     }
 
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
 /* returns 1 on problem encountered or 0 for success */
diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index c5cfe0b..be9a232 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -141,8 +141,8 @@ static void usbredir_interrupt_packet(void *priv, uint64_t id,
     struct usb_redir_interrupt_packet_header *interrupt_header,
     uint8_t *data, int data_len);
 
-static int usbredir_handle_status(USBRedirDevice *dev,
-                                       int status, int actual_len);
+static void usbredir_handle_status(USBRedirDevice *dev, USBPacket *p,
+    int status);
 
 #define VERSION "qemu usb-redir guest " QEMU_VERSION
 
@@ -443,7 +443,7 @@ static void usbredir_handle_reset(USBDevice *udev)
     usbredirparser_do_write(dev->parser);
 }
 
-static int usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
+static void usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
                                      uint8_t ep)
 {
     int status, len;
@@ -500,7 +500,7 @@ static int usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
                 !dev->endpoint[EP2I(ep)].bufpq_prefilled) {
             if (dev->endpoint[EP2I(ep)].bufpq_size <
                     dev->endpoint[EP2I(ep)].bufpq_target_size) {
-                return usbredir_handle_status(dev, 0, 0);
+                return;
             }
             dev->endpoint[EP2I(ep)].bufpq_prefilled = 1;
         }
@@ -514,27 +514,23 @@ static int usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
             /* Check iso_error for stream errors, otherwise its an underrun */
             status = dev->endpoint[EP2I(ep)].iso_error;
             dev->endpoint[EP2I(ep)].iso_error = 0;
-            return status ? USB_RET_IOERROR : 0;
+            p->status = status ? USB_RET_IOERROR : USB_RET_SUCCESS;
+            return;
         }
         DPRINTF2("iso-token-in ep %02X status %d len %d queue-size: %d\n", ep,
                  isop->status, isop->len, dev->endpoint[EP2I(ep)].bufpq_size);
 
         status = isop->status;
-        if (status != usb_redir_success) {
-            bufp_free(dev, isop, ep);
-            return USB_RET_IOERROR;
-        }
-
         len = isop->len;
         if (len > p->iov.size) {
             ERROR("received iso data is larger then packet ep %02X (%d > %d)\n",
                   ep, len, (int)p->iov.size);
-            bufp_free(dev, isop, ep);
-            return USB_RET_BABBLE;
+            len = p->iov.size;
+            status = usb_redir_babble;
         }
         usb_packet_copy(p, isop->data, len);
         bufp_free(dev, isop, ep);
-        return len;
+        usbredir_handle_status(dev, p, status);
     } else {
         /* If the stream was not started because of a pending error don't
            send the packet to the usb-host */
@@ -554,7 +550,7 @@ static int usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
         dev->endpoint[EP2I(ep)].iso_error = 0;
         DPRINTF2("iso-token-out ep %02X status %d len %zd\n", ep, status,
                  p->iov.size);
-        return usbredir_handle_status(dev, status, p->iov.size);
+        usbredir_handle_status(dev, p, status);
     }
 }
 
@@ -572,7 +568,7 @@ static void usbredir_stop_iso_stream(USBRedirDevice *dev, uint8_t ep)
     usbredir_free_bufpq(dev, ep);
 }
 
-static int usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
+static void usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
                                       uint8_t ep)
 {
     struct usb_redir_bulk_packet_header bulk_packet;
@@ -581,7 +577,8 @@ static int usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
     DPRINTF("bulk-out ep %02X len %zd id %"PRIu64"\n", ep, size, p->id);
 
     if (usbredir_already_in_flight(dev, p->id)) {
-        return USB_RET_ASYNC;
+        p->status = USB_RET_ASYNC;
+        return;
     }
 
     bulk_packet.endpoint  = ep;
@@ -608,10 +605,10 @@ static int usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
                                         &bulk_packet, buf, size);
     }
     usbredirparser_do_write(dev->parser);
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
-static int usbredir_handle_interrupt_data(USBRedirDevice *dev,
+static void usbredir_handle_interrupt_data(USBRedirDevice *dev,
                                            USBPacket *p, uint8_t ep)
 {
     if (ep & USB_DIR_IN) {
@@ -643,28 +640,25 @@ static int usbredir_handle_interrupt_data(USBRedirDevice *dev,
             status = dev->endpoint[EP2I(ep)].interrupt_error;
             dev->endpoint[EP2I(ep)].interrupt_error = 0;
             if (status) {
-                return usbredir_handle_status(dev, status, 0);
+                usbredir_handle_status(dev, p, status);
+            } else {
+                p->status = USB_RET_NAK;
             }
-            return USB_RET_NAK;
+            return;
         }
         DPRINTF("interrupt-token-in ep %02X status %d len %d\n", ep,
                 intp->status, intp->len);
 
         status = intp->status;
-        if (status != usb_redir_success) {
-            bufp_free(dev, intp, ep);
-            return usbredir_handle_status(dev, status, 0);
-        }
-
         len = intp->len;
         if (len > p->iov.size) {
             ERROR("received int data is larger then packet ep %02X\n", ep);
-            bufp_free(dev, intp, ep);
-            return USB_RET_BABBLE;
+            len = p->iov.size;
+            status = usb_redir_babble;
         }
         usb_packet_copy(p, intp->data, len);
         bufp_free(dev, intp, ep);
-        return len;
+        usbredir_handle_status(dev, p, status);
     } else {
         /* Output interrupt endpoint, normal async operation */
         struct usb_redir_interrupt_packet_header interrupt_packet;
@@ -674,7 +668,8 @@ static int usbredir_handle_interrupt_data(USBRedirDevice *dev,
                 p->iov.size, p->id);
 
         if (usbredir_already_in_flight(dev, p->id)) {
-            return USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
+            return;
         }
 
         interrupt_packet.endpoint  = ep;
@@ -685,7 +680,7 @@ static int usbredir_handle_interrupt_data(USBRedirDevice *dev,
         usbredirparser_send_interrupt_packet(dev->parser, p->id,
                                         &interrupt_packet, buf, p->iov.size);
         usbredirparser_do_write(dev->parser);
-        return USB_RET_ASYNC;
+        p->status = USB_RET_ASYNC;
     }
 }
 
@@ -705,7 +700,7 @@ static void usbredir_stop_interrupt_receiving(USBRedirDevice *dev,
     usbredir_free_bufpq(dev, ep);
 }
 
-static int usbredir_handle_data(USBDevice *udev, USBPacket *p)
+static void usbredir_handle_data(USBDevice *udev, USBPacket *p)
 {
     USBRedirDevice *dev = DO_UPCAST(USBRedirDevice, dev, udev);
     uint8_t ep;
@@ -718,21 +713,26 @@ static int usbredir_handle_data(USBDevice *udev, USBPacket *p)
     switch (dev->endpoint[EP2I(ep)].type) {
     case USB_ENDPOINT_XFER_CONTROL:
         ERROR("handle_data called for control transfer on ep %02X\n", ep);
-        return USB_RET_NAK;
+        p->status = USB_RET_NAK;
+        break;
     case USB_ENDPOINT_XFER_ISOC:
-        return usbredir_handle_iso_data(dev, p, ep);
+        usbredir_handle_iso_data(dev, p, ep);
+        break;
     case USB_ENDPOINT_XFER_BULK:
         if (p->state == USB_PACKET_SETUP && p->pid == USB_TOKEN_IN &&
                 p->ep->pipeline) {
-            return USB_RET_ADD_TO_QUEUE;
+            p->status = USB_RET_ADD_TO_QUEUE;
+            break;
         }
-        return usbredir_handle_bulk_data(dev, p, ep);
+        usbredir_handle_bulk_data(dev, p, ep);
+        break;
     case USB_ENDPOINT_XFER_INT:
-        return usbredir_handle_interrupt_data(dev, p, ep);
+        usbredir_handle_interrupt_data(dev, p, ep);
+        break;
     default:
         ERROR("handle_data ep %02X has unknown type %d\n", ep,
               dev->endpoint[EP2I(ep)].type);
-        return USB_RET_NAK;
+        p->status = USB_RET_NAK;
     }
 }
 
@@ -743,7 +743,7 @@ static void usbredir_flush_ep_queue(USBDevice *dev, USBEndpoint *ep)
     }
 }
 
-static int usbredir_set_config(USBRedirDevice *dev, USBPacket *p,
+static void usbredir_set_config(USBRedirDevice *dev, USBPacket *p,
                                 int config)
 {
     struct usb_redir_set_configuration_header set_config;
@@ -768,19 +768,19 @@ static int usbredir_set_config(USBRedirDevice *dev, USBPacket *p,
     set_config.configuration = config;
     usbredirparser_send_set_configuration(dev->parser, p->id, &set_config);
     usbredirparser_do_write(dev->parser);
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
-static int usbredir_get_config(USBRedirDevice *dev, USBPacket *p)
+static void usbredir_get_config(USBRedirDevice *dev, USBPacket *p)
 {
     DPRINTF("get config id %"PRIu64"\n", p->id);
 
     usbredirparser_send_get_configuration(dev->parser, p->id);
     usbredirparser_do_write(dev->parser);
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
-static int usbredir_set_interface(USBRedirDevice *dev, USBPacket *p,
+static void usbredir_set_interface(USBRedirDevice *dev, USBPacket *p,
                                    int interface, int alt)
 {
     struct usb_redir_set_alt_setting_header set_alt;
@@ -808,10 +808,10 @@ static int usbredir_set_interface(USBRedirDevice *dev, USBPacket *p,
     set_alt.alt = alt;
     usbredirparser_send_set_alt_setting(dev->parser, p->id, &set_alt);
     usbredirparser_do_write(dev->parser);
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
-static int usbredir_get_interface(USBRedirDevice *dev, USBPacket *p,
+static void usbredir_get_interface(USBRedirDevice *dev, USBPacket *p,
                                    int interface)
 {
     struct usb_redir_get_alt_setting_header get_alt;
@@ -821,17 +821,18 @@ static int usbredir_get_interface(USBRedirDevice *dev, USBPacket *p,
     get_alt.interface = interface;
     usbredirparser_send_get_alt_setting(dev->parser, p->id, &get_alt);
     usbredirparser_do_write(dev->parser);
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
-static int usbredir_handle_control(USBDevice *udev, USBPacket *p,
+static void usbredir_handle_control(USBDevice *udev, USBPacket *p,
         int request, int value, int index, int length, uint8_t *data)
 {
     USBRedirDevice *dev = DO_UPCAST(USBRedirDevice, dev, udev);
     struct usb_redir_control_packet_header control_packet;
 
     if (usbredir_already_in_flight(dev, p->id)) {
-        return USB_RET_ASYNC;
+        p->status = USB_RET_ASYNC;
+        return;
     }
 
     /* Special cases for certain standard device requests */
@@ -839,15 +840,19 @@ static int usbredir_handle_control(USBDevice *udev, USBPacket *p,
     case DeviceOutRequest | USB_REQ_SET_ADDRESS:
         DPRINTF("set address %d\n", value);
         dev->dev.addr = value;
-        return 0;
+        return;
     case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
-        return usbredir_set_config(dev, p, value & 0xff);
+        usbredir_set_config(dev, p, value & 0xff);
+        return;
     case DeviceRequest | USB_REQ_GET_CONFIGURATION:
-        return usbredir_get_config(dev, p);
+        usbredir_get_config(dev, p);
+        return;
     case InterfaceOutRequest | USB_REQ_SET_INTERFACE:
-        return usbredir_set_interface(dev, p, index, value);
+        usbredir_set_interface(dev, p, index, value);
+        return;
     case InterfaceRequest | USB_REQ_GET_INTERFACE:
-        return usbredir_get_interface(dev, p, index);
+        usbredir_get_interface(dev, p, index);
+        return;
     }
 
     /* Normal ctrl requests, note request is (bRequestType << 8) | bRequest */
@@ -871,7 +876,7 @@ static int usbredir_handle_control(USBDevice *udev, USBPacket *p,
                                            &control_packet, data, length);
     }
     usbredirparser_do_write(dev->parser);
-    return USB_RET_ASYNC;
+    p->status = USB_RET_ASYNC;
 }
 
 /*
@@ -1159,29 +1164,34 @@ error:
  * usbredirparser packet complete callbacks
  */
 
-static int usbredir_handle_status(USBRedirDevice *dev,
-                                       int status, int actual_len)
+static void usbredir_handle_status(USBRedirDevice *dev, USBPacket *p,
+    int status)
 {
     switch (status) {
     case usb_redir_success:
-        return actual_len;
+        p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
+        break;
     case usb_redir_stall:
-        return USB_RET_STALL;
+        p->status = USB_RET_STALL;
+        break;
     case usb_redir_cancelled:
         /*
          * When the usbredir-host unredirects a device, it will report a status
          * of cancelled for all pending packets, followed by a disconnect msg.
          */
-        return USB_RET_IOERROR;
+        p->status = USB_RET_IOERROR;
+        break;
     case usb_redir_inval:
         WARNING("got invalid param error from usb-host?\n");
-        return USB_RET_IOERROR;
+        p->status = USB_RET_IOERROR;
+        break;
     case usb_redir_babble:
-        return USB_RET_BABBLE;
+        p->status = USB_RET_BABBLE;
+        break;
     case usb_redir_ioerror:
     case usb_redir_timeout:
     default:
-        return USB_RET_IOERROR;
+        p->status = USB_RET_IOERROR;
     }
 }
 
@@ -1412,7 +1422,6 @@ static void usbredir_configuration_status(void *priv, uint64_t id,
 {
     USBRedirDevice *dev = priv;
     USBPacket *p;
-    int len = 0;
 
     DPRINTF("set config status %d config %d id %"PRIu64"\n",
             config_status->status, config_status->configuration, id);
@@ -1421,9 +1430,9 @@ static void usbredir_configuration_status(void *priv, uint64_t id,
     if (p) {
         if (dev->dev.setup_buf[0] & USB_DIR_IN) {
             dev->dev.data_buf[0] = config_status->configuration;
-            len = 1;
+            p->actual_length = 1;
         }
-        p->result = usbredir_handle_status(dev, config_status->status, len);
+        usbredir_handle_status(dev, p, config_status->status);
         usb_generic_async_ctrl_complete(&dev->dev, p);
     }
 }
@@ -1433,7 +1442,6 @@ static void usbredir_alt_setting_status(void *priv, uint64_t id,
 {
     USBRedirDevice *dev = priv;
     USBPacket *p;
-    int len = 0;
 
     DPRINTF("alt status %d intf %d alt %d id: %"PRIu64"\n",
             alt_setting_status->status, alt_setting_status->interface,
@@ -1443,10 +1451,9 @@ static void usbredir_alt_setting_status(void *priv, uint64_t id,
     if (p) {
         if (dev->dev.setup_buf[0] & USB_DIR_IN) {
             dev->dev.data_buf[0] = alt_setting_status->alt;
-            len = 1;
+            p->actual_length = 1;
         }
-        p->result =
-            usbredir_handle_status(dev, alt_setting_status->status, len);
+        usbredir_handle_status(dev, p, alt_setting_status->status);
         usb_generic_async_ctrl_complete(&dev->dev, p);
     }
 }
@@ -1522,18 +1529,18 @@ static void usbredir_control_packet(void *priv, uint64_t id,
 
     p = usbredir_find_packet_by_id(dev, 0, id);
     if (p) {
-        len = usbredir_handle_status(dev, control_packet->status, len);
-        if (len > 0) {
+        usbredir_handle_status(dev, p, control_packet->status);
+        if (data_len > 0) {
             usbredir_log_data(dev, "ctrl data in:", data, data_len);
-            if (data_len <= sizeof(dev->dev.data_buf)) {
-                memcpy(dev->dev.data_buf, data, data_len);
-            } else {
+            if (data_len > sizeof(dev->dev.data_buf)) {
                 ERROR("ctrl buffer too small (%d > %zu)\n",
                       data_len, sizeof(dev->dev.data_buf));
-                len = USB_RET_STALL;
+                p->status = USB_RET_STALL;
+                data_len = len = sizeof(dev->dev.data_buf);
             }
+            memcpy(dev->dev.data_buf, data, data_len);
         }
-        p->result = len;
+        p->actual_length = len;
         usb_generic_async_ctrl_complete(&dev->dev, p);
     }
     free(data);
@@ -1554,23 +1561,23 @@ static void usbredir_bulk_packet(void *priv, uint64_t id,
     p = usbredir_find_packet_by_id(dev, ep, id);
     if (p) {
         size_t size = (p->combined) ? p->combined->iov.size : p->iov.size;
-        len = usbredir_handle_status(dev, bulk_packet->status, len);
-        if (len > 0) {
+        usbredir_handle_status(dev, p, bulk_packet->status);
+        if (data_len > 0) {
             usbredir_log_data(dev, "bulk data in:", data, data_len);
-            if (data_len <= size) {
-                if (p->combined) {
-                    iov_from_buf(p->combined->iov.iov, p->combined->iov.niov,
-                                 0, data, data_len);
-                } else {
-                    usb_packet_copy(p, data, data_len);
-                }
-            } else {
+            if (data_len > size) {
                 ERROR("bulk got more data then requested (%d > %zd)\n",
                       data_len, p->iov.size);
-                len = USB_RET_BABBLE;
+                p->status = USB_RET_BABBLE;
+                data_len = len = size;
+            }
+            if (p->combined) {
+                iov_from_buf(p->combined->iov.iov, p->combined->iov.niov,
+                             0, data, data_len);
+            } else {
+                usb_packet_copy(p, data, data_len);
             }
         }
-        p->result = len;
+        p->actual_length = len;
         if (p->pid == USB_TOKEN_IN && p->ep->pipeline) {
             usb_combined_input_packet_complete(&dev->dev, p);
         } else {
@@ -1632,12 +1639,10 @@ static void usbredir_interrupt_packet(void *priv, uint64_t id,
         /* bufp_alloc also adds the packet to the ep queue */
         bufp_alloc(dev, data, data_len, interrupt_packet->status, ep);
     } else {
-        int len = interrupt_packet->length;
-
         USBPacket *p = usbredir_find_packet_by_id(dev, ep, id);
         if (p) {
-            p->result = usbredir_handle_status(dev,
-                                               interrupt_packet->status, len);
+            usbredir_handle_status(dev, p, interrupt_packet->status);
+            p->actual_length = interrupt_packet->length;
             usb_packet_complete(&dev->dev, p);
         }
     }