qemu

xen-usb.c (31990B)

---

 /*
  *  xen paravirt usb device backend
  *
  *  (c) Juergen Gross <jgross@suse.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; under version 2 of the License.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, see <http://www.gnu.org/licenses/>.
  *
  *  Contributions after 2012-01-13 are licensed under the terms of the
  *  GNU GPL, version 2 or (at your option) any later version.
  */
 
 #include "qemu/osdep.h"
 #include <libusb.h>
 #include <sys/user.h>
 
 #include "qemu/config-file.h"
 #include "qemu/main-loop.h"
 #include "qemu/option.h"
 #include "hw/usb.h"
 #include "hw/xen/xen-legacy-backend.h"
 #include "monitor/qdev.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qstring.h"
 
 #include "hw/xen/interface/io/usbif.h"
 
 /*
  * Check for required support of usbif.h: USBIF_SHORT_NOT_OK was the last
  * macro added we rely on.
  */
 #ifdef USBIF_SHORT_NOT_OK
 
 #define TR(xendev, lvl, fmt, args...)                               \
     {                                                               \
         struct timeval tv;                                          \
                                                                     \
         gettimeofday(&tv, NULL);                                    \
         xen_pv_printf(xendev, lvl, "%8ld.%06ld xen-usb(%s):" fmt,   \
                       tv.tv_sec, tv.tv_usec, __func__, ##args);     \
     }
 #define TR_BUS(xendev, fmt, args...) TR(xendev, 2, fmt, ##args)
 #define TR_REQ(xendev, fmt, args...) TR(xendev, 3, fmt, ##args)
 
 #define USBBACK_MAXPORTS        USBIF_PIPE_PORT_MASK
 #define USB_DEV_ADDR_SIZE       (USBIF_PIPE_DEV_MASK + 1)
 
 /* USB wire protocol: structure describing control request parameter. */
 struct usbif_ctrlrequest {
     uint8_t    bRequestType;
     uint8_t    bRequest;
     uint16_t   wValue;
     uint16_t   wIndex;
     uint16_t   wLength;
 };
 
 struct usbback_info;
 struct usbback_req;
 
 struct usbback_stub {
     USBDevice     *dev;
     USBPort       port;
     unsigned int  speed;
     bool          attached;
     QTAILQ_HEAD(, usbback_req) submit_q;
 };
 
 struct usbback_req {
     struct usbback_info      *usbif;
     struct usbback_stub      *stub;
     struct usbif_urb_request req;
     USBPacket                packet;
 
     unsigned int             nr_buffer_segs; /* # of transfer_buffer segments */
     unsigned int             nr_extra_segs;  /* # of iso_frame_desc segments  */
 
     QTAILQ_ENTRY(usbback_req) q;
 
     void                     *buffer;
     void                     *isoc_buffer;
     struct libusb_transfer   *xfer;
 
     bool                     cancelled;
 };
 
 struct usbback_hotplug {
     QSIMPLEQ_ENTRY(usbback_hotplug) q;
     unsigned                 port;
 };
 
 struct usbback_info {
     struct XenLegacyDevice         xendev;  /* must be first */
     USBBus                   bus;
     void                     *urb_sring;
     void                     *conn_sring;
     struct usbif_urb_back_ring urb_ring;
     struct usbif_conn_back_ring conn_ring;
     int                      num_ports;
     int                      usb_ver;
     bool                     ring_error;
     QTAILQ_HEAD(, usbback_req) req_free_q;
     QSIMPLEQ_HEAD(, usbback_hotplug) hotplug_q;
     struct usbback_stub      ports[USBBACK_MAXPORTS];
     struct usbback_stub      *addr_table[USB_DEV_ADDR_SIZE];
     QEMUBH                   *bh;
 };
 
 static struct usbback_req *usbback_get_req(struct usbback_info *usbif)
 {
     struct usbback_req *usbback_req;
 
     if (QTAILQ_EMPTY(&usbif->req_free_q)) {
         usbback_req = g_new0(struct usbback_req, 1);
     } else {
         usbback_req = QTAILQ_FIRST(&usbif->req_free_q);
         QTAILQ_REMOVE(&usbif->req_free_q, usbback_req, q);
     }
     return usbback_req;
 }
 
 static void usbback_put_req(struct usbback_req *usbback_req)
 {
     struct usbback_info *usbif;
 
     usbif = usbback_req->usbif;
     memset(usbback_req, 0, sizeof(*usbback_req));
     QTAILQ_INSERT_HEAD(&usbif->req_free_q, usbback_req, q);
 }
 
 static int usbback_gnttab_map(struct usbback_req *usbback_req)
 {
     unsigned int nr_segs, i, prot;
     uint32_t ref[USBIF_MAX_SEGMENTS_PER_REQUEST];
     struct usbback_info *usbif = usbback_req->usbif;
     struct XenLegacyDevice *xendev = &usbif->xendev;
     struct usbif_request_segment *seg;
     void *addr;
 
     nr_segs = usbback_req->nr_buffer_segs + usbback_req->nr_extra_segs;
     if (!nr_segs) {
         return 0;
     }
 
     if (nr_segs > USBIF_MAX_SEGMENTS_PER_REQUEST) {
         xen_pv_printf(xendev, 0, "bad number of segments in request (%d)\n",
                       nr_segs);
         return -EINVAL;
     }
 
     for (i = 0; i < nr_segs; i++) {
         if ((unsigned)usbback_req->req.seg[i].offset +
             (unsigned)usbback_req->req.seg[i].length > XC_PAGE_SIZE) {
             xen_pv_printf(xendev, 0, "segment crosses page boundary\n");
             return -EINVAL;
         }
     }
 
     if (usbback_req->nr_buffer_segs) {
         prot = PROT_READ;
         if (usbif_pipein(usbback_req->req.pipe)) {
                 prot |= PROT_WRITE;
         }
         for (i = 0; i < usbback_req->nr_buffer_segs; i++) {
             ref[i] = usbback_req->req.seg[i].gref;
         }
         usbback_req->buffer =
             xen_be_map_grant_refs(xendev, ref, usbback_req->nr_buffer_segs,
                                   prot);
 
         if (!usbback_req->buffer) {
             return -ENOMEM;
         }
 
         for (i = 0; i < usbback_req->nr_buffer_segs; i++) {
             seg = usbback_req->req.seg + i;
             addr = usbback_req->buffer + i * XC_PAGE_SIZE + seg->offset;
             qemu_iovec_add(&usbback_req->packet.iov, addr, seg->length);
         }
     }
 
     if (!usbif_pipeisoc(usbback_req->req.pipe)) {
         return 0;
     }
 
     /*
      * Right now isoc requests are not supported.
      * Prepare supporting those by doing the work needed on the guest
      * interface side.
      */
 
     if (!usbback_req->nr_extra_segs) {
         xen_pv_printf(xendev, 0, "iso request without descriptor segments\n");
         return -EINVAL;
     }
 
     prot = PROT_READ | PROT_WRITE;
     for (i = 0; i < usbback_req->nr_extra_segs; i++) {
         ref[i] = usbback_req->req.seg[i + usbback_req->req.nr_buffer_segs].gref;
     }
     usbback_req->isoc_buffer =
         xen_be_map_grant_refs(xendev, ref, usbback_req->nr_extra_segs,
                               prot);
 
     if (!usbback_req->isoc_buffer) {
         return -ENOMEM;
     }
 
     return 0;
 }
 
 static int usbback_init_packet(struct usbback_req *usbback_req)
 {
     struct XenLegacyDevice *xendev = &usbback_req->usbif->xendev;
     USBPacket *packet = &usbback_req->packet;
     USBDevice *dev = usbback_req->stub->dev;
     USBEndpoint *ep;
     unsigned int pid, ep_nr;
     bool sok;
     int ret = 0;
 
     qemu_iovec_init(&packet->iov, USBIF_MAX_SEGMENTS_PER_REQUEST);
     pid = usbif_pipein(usbback_req->req.pipe) ? USB_TOKEN_IN : USB_TOKEN_OUT;
     ep_nr = usbif_pipeendpoint(usbback_req->req.pipe);
     sok = !!(usbback_req->req.transfer_flags & USBIF_SHORT_NOT_OK);
     if (usbif_pipectrl(usbback_req->req.pipe)) {
         ep_nr = 0;
         sok = false;
     }
     ep = usb_ep_get(dev, pid, ep_nr);
     usb_packet_setup(packet, pid, ep, 0, 1, sok, true);
 
     switch (usbif_pipetype(usbback_req->req.pipe)) {
     case USBIF_PIPE_TYPE_ISOC:
         TR_REQ(xendev, "iso transfer %s: buflen: %x, %d frames\n",
                (pid == USB_TOKEN_IN) ? "in" : "out",
                usbback_req->req.buffer_length,
                usbback_req->req.u.isoc.nr_frame_desc_segs);
         ret = -EINVAL;  /* isoc not implemented yet */
         break;
 
     case USBIF_PIPE_TYPE_INT:
         TR_REQ(xendev, "int transfer %s: buflen: %x\n",
                (pid == USB_TOKEN_IN) ? "in" : "out",
                usbback_req->req.buffer_length);
         break;
 
     case USBIF_PIPE_TYPE_CTRL:
         packet->parameter = *(uint64_t *)usbback_req->req.u.ctrl;
         TR_REQ(xendev, "ctrl parameter: %"PRIx64", buflen: %x\n",
                packet->parameter,
                usbback_req->req.buffer_length);
         break;
 
     case USBIF_PIPE_TYPE_BULK:
         TR_REQ(xendev, "bulk transfer %s: buflen: %x\n",
                (pid == USB_TOKEN_IN) ? "in" : "out",
                usbback_req->req.buffer_length);
         break;
     default:
         ret = -EINVAL;
         break;
     }
 
     return ret;
 }
 
 static void usbback_do_response(struct usbback_req *usbback_req, int32_t status,
                                 int32_t actual_length, int32_t error_count)
 {
     struct usbback_info *usbif;
     struct usbif_urb_response *res;
     struct XenLegacyDevice *xendev;
     unsigned int notify;
 
     usbif = usbback_req->usbif;
     xendev = &usbif->xendev;
 
     TR_REQ(xendev, "id %d, status %d, length %d, errcnt %d\n",
            usbback_req->req.id, status, actual_length, error_count);
 
     if (usbback_req->packet.iov.iov) {
         qemu_iovec_destroy(&usbback_req->packet.iov);
     }
 
     if (usbback_req->buffer) {
         xen_be_unmap_grant_refs(xendev, usbback_req->buffer,
                                 usbback_req->nr_buffer_segs);
         usbback_req->buffer = NULL;
     }
 
     if (usbback_req->isoc_buffer) {
         xen_be_unmap_grant_refs(xendev, usbback_req->isoc_buffer,
                                 usbback_req->nr_extra_segs);
         usbback_req->isoc_buffer = NULL;
     }
 
     if (usbif->urb_sring) {
         res = RING_GET_RESPONSE(&usbif->urb_ring, usbif->urb_ring.rsp_prod_pvt);
         res->id = usbback_req->req.id;
         res->status = status;
         res->actual_length = actual_length;
         res->error_count = error_count;
         res->start_frame = 0;
         usbif->urb_ring.rsp_prod_pvt++;
         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&usbif->urb_ring, notify);
 
         if (notify) {
             xen_pv_send_notify(xendev);
         }
     }
 
     if (!usbback_req->cancelled)
         usbback_put_req(usbback_req);
 }
 
 static void usbback_do_response_ret(struct usbback_req *usbback_req,
                                     int32_t status)
 {
     usbback_do_response(usbback_req, status, 0, 0);
 }
 
 static int32_t usbback_xlat_status(int status)
 {
     switch (status) {
     case USB_RET_SUCCESS:
         return 0;
     case USB_RET_NODEV:
         return -ENODEV;
     case USB_RET_STALL:
         return -EPIPE;
     case USB_RET_BABBLE:
         return -EOVERFLOW;
     case USB_RET_IOERROR:
         return -EPROTO;
     }
 
     return -ESHUTDOWN;
 }
 
 static void usbback_packet_complete(struct usbback_req *usbback_req)
 {
     USBPacket *packet = &usbback_req->packet;
     int32_t status;
 
     QTAILQ_REMOVE(&usbback_req->stub->submit_q, usbback_req, q);
 
     status = usbback_xlat_status(packet->status);
     usbback_do_response(usbback_req, status, packet->actual_length, 0);
 }
 
 static void usbback_set_address(struct usbback_info *usbif,
                                 struct usbback_stub *stub,
                                 unsigned int cur_addr, unsigned int new_addr)
 {
     if (cur_addr) {
         usbif->addr_table[cur_addr] = NULL;
     }
     if (new_addr) {
         usbif->addr_table[new_addr] = stub;
     }
 }
 
 static void usbback_cancel_req(struct usbback_req *usbback_req)
 {
     if (usb_packet_is_inflight(&usbback_req->packet)) {
         usb_cancel_packet(&usbback_req->packet);
         QTAILQ_REMOVE(&usbback_req->stub->submit_q, usbback_req, q);
         usbback_req->cancelled = true;
         usbback_do_response_ret(usbback_req, -EPROTO);
     }
 }
 
 static void usbback_process_unlink_req(struct usbback_req *usbback_req)
 {
     struct usbback_info *usbif;
     struct usbback_req *unlink_req;
     unsigned int id, devnum;
     int ret;
 
     usbif = usbback_req->usbif;
     ret = 0;
     id = usbback_req->req.u.unlink.unlink_id;
     TR_REQ(&usbif->xendev, "unlink id %d\n", id);
     devnum = usbif_pipedevice(usbback_req->req.pipe);
     if (unlikely(devnum == 0)) {
         usbback_req->stub = usbif->ports +
                             usbif_pipeportnum(usbback_req->req.pipe) - 1;
         if (unlikely(!usbback_req->stub)) {
             ret = -ENODEV;
             goto fail_response;
         }
     } else {
         if (unlikely(!usbif->addr_table[devnum])) {
             ret = -ENODEV;
             goto fail_response;
         }
         usbback_req->stub = usbif->addr_table[devnum];
     }
 
     QTAILQ_FOREACH(unlink_req, &usbback_req->stub->submit_q, q) {
         if (unlink_req->req.id == id) {
             usbback_cancel_req(unlink_req);
             break;
         }
     }
 
 fail_response:
     usbback_do_response_ret(usbback_req, ret);
 }
 
 /*
  * Checks whether a request can be handled at once or should be forwarded
  * to the usb framework.
  * Return value is:
  * 0 in case of usb framework is needed
  * 1 in case of local handling (no error)
  * The request response has been queued already if return value not 0.
  */
 static int usbback_check_and_submit(struct usbback_req *usbback_req)
 {
     struct usbback_info *usbif;
     unsigned int devnum;
     struct usbback_stub *stub;
     struct usbif_ctrlrequest *ctrl;
     int ret;
     uint16_t wValue;
 
     usbif = usbback_req->usbif;
     stub = NULL;
     devnum = usbif_pipedevice(usbback_req->req.pipe);
     ctrl = (struct usbif_ctrlrequest *)usbback_req->req.u.ctrl;
     wValue = le16_to_cpu(ctrl->wValue);
 
     /*
      * When the device is first connected or resetted, USB device has no
      * address. In this initial state, following requests are sent to device
      * address (#0),
      *
      *  1. GET_DESCRIPTOR (with Descriptor Type is "DEVICE") is sent,
      *     and OS knows what device is connected to.
      *
      *  2. SET_ADDRESS is sent, and then device has its address.
      *
      * In the next step, SET_CONFIGURATION is sent to addressed device, and
      * then the device is finally ready to use.
      */
     if (unlikely(devnum == 0)) {
         stub = usbif->ports + usbif_pipeportnum(usbback_req->req.pipe) - 1;
         if (!stub->dev || !stub->attached) {
             ret = -ENODEV;
             goto do_response;
         }
 
         switch (ctrl->bRequest) {
         case USB_REQ_GET_DESCRIPTOR:
             /*
              * GET_DESCRIPTOR request to device #0.
              * through normal transfer.
              */
             TR_REQ(&usbif->xendev, "devnum 0 GET_DESCRIPTOR\n");
             usbback_req->stub = stub;
             return 0;
         case USB_REQ_SET_ADDRESS:
             /*
              * SET_ADDRESS request to device #0.
              * add attached device to addr_table.
              */
             TR_REQ(&usbif->xendev, "devnum 0 SET_ADDRESS\n");
             usbback_set_address(usbif, stub, 0, wValue);
             ret = 0;
             break;
         default:
             ret = -EINVAL;
             break;
         }
         goto do_response;
     }
 
     if (unlikely(!usbif->addr_table[devnum])) {
             ret = -ENODEV;
             goto do_response;
     }
     usbback_req->stub = usbif->addr_table[devnum];
 
     /*
      * Check special request
      */
     if (ctrl->bRequest != USB_REQ_SET_ADDRESS) {
         return 0;
     }
 
     /*
      * SET_ADDRESS request to addressed device.
      * change addr or remove from addr_table.
      */
     usbback_set_address(usbif, usbback_req->stub, devnum, wValue);
     ret = 0;
 
 do_response:
     usbback_do_response_ret(usbback_req, ret);
     return 1;
 }
 
 static void usbback_dispatch(struct usbback_req *usbback_req)
 {
     int ret;
     unsigned int devnum;
     struct usbback_info *usbif;
 
     usbif = usbback_req->usbif;
 
     TR_REQ(&usbif->xendev, "start req_id %d pipe %08x\n", usbback_req->req.id,
            usbback_req->req.pipe);
 
     /* unlink request */
     if (unlikely(usbif_pipeunlink(usbback_req->req.pipe))) {
         usbback_process_unlink_req(usbback_req);
         return;
     }
 
     if (usbif_pipectrl(usbback_req->req.pipe)) {
         if (usbback_check_and_submit(usbback_req)) {
             return;
         }
     } else {
         devnum = usbif_pipedevice(usbback_req->req.pipe);
         usbback_req->stub = usbif->addr_table[devnum];
 
         if (!usbback_req->stub || !usbback_req->stub->attached) {
             ret = -ENODEV;
             goto fail_response;
         }
     }
 
     QTAILQ_INSERT_TAIL(&usbback_req->stub->submit_q, usbback_req, q);
 
     usbback_req->nr_buffer_segs = usbback_req->req.nr_buffer_segs;
     usbback_req->nr_extra_segs = usbif_pipeisoc(usbback_req->req.pipe) ?
                                  usbback_req->req.u.isoc.nr_frame_desc_segs : 0;
 
     ret = usbback_init_packet(usbback_req);
     if (ret) {
         xen_pv_printf(&usbif->xendev, 0, "invalid request\n");
         ret = -ESHUTDOWN;
         goto fail_free_urb;
     }
 
     ret = usbback_gnttab_map(usbback_req);
     if (ret) {
         xen_pv_printf(&usbif->xendev, 0, "invalid buffer, ret=%d\n", ret);
         ret = -ESHUTDOWN;
         goto fail_free_urb;
     }
 
     usb_handle_packet(usbback_req->stub->dev, &usbback_req->packet);
     if (usbback_req->packet.status != USB_RET_ASYNC) {
         usbback_packet_complete(usbback_req);
     }
     return;
 
 fail_free_urb:
     QTAILQ_REMOVE(&usbback_req->stub->submit_q, usbback_req, q);
 
 fail_response:
     usbback_do_response_ret(usbback_req, ret);
 }
 
 static void usbback_hotplug_notify(struct usbback_info *usbif)
 {
     struct usbif_conn_back_ring *ring = &usbif->conn_ring;
     struct usbif_conn_request req;
     struct usbif_conn_response *res;
     struct usbback_hotplug *usb_hp;
     unsigned int notify;
 
     if (!usbif->conn_sring) {
         return;
     }
 
     /* Check for full ring. */
     if ((RING_SIZE(ring) - ring->rsp_prod_pvt - ring->req_cons) == 0) {
         xen_pv_send_notify(&usbif->xendev);
         return;
     }
 
     usb_hp = QSIMPLEQ_FIRST(&usbif->hotplug_q);
     QSIMPLEQ_REMOVE_HEAD(&usbif->hotplug_q, q);
 
     RING_COPY_REQUEST(ring, ring->req_cons, &req);
     ring->req_cons++;
     ring->sring->req_event = ring->req_cons + 1;
 
     res = RING_GET_RESPONSE(ring, ring->rsp_prod_pvt);
     res->id = req.id;
     res->portnum = usb_hp->port;
     res->speed = usbif->ports[usb_hp->port - 1].speed;
     ring->rsp_prod_pvt++;
     RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(ring, notify);
 
     if (notify) {
         xen_pv_send_notify(&usbif->xendev);
     }
 
     TR_BUS(&usbif->xendev, "hotplug port %d speed %d\n", usb_hp->port,
            res->speed);
 
     g_free(usb_hp);
 
     if (!QSIMPLEQ_EMPTY(&usbif->hotplug_q)) {
         qemu_bh_schedule(usbif->bh);
     }
 }
 
 static void usbback_bh(void *opaque)
 {
     struct usbback_info *usbif;
     struct usbif_urb_back_ring *urb_ring;
     struct usbback_req *usbback_req;
     RING_IDX rc, rp;
     unsigned int more_to_do;
 
     usbif = opaque;
     if (usbif->ring_error) {
         return;
     }
 
     if (!QSIMPLEQ_EMPTY(&usbif->hotplug_q)) {
         usbback_hotplug_notify(usbif);
     }
 
     urb_ring = &usbif->urb_ring;
     rc = urb_ring->req_cons;
     rp = urb_ring->sring->req_prod;
     xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
 
     if (RING_REQUEST_PROD_OVERFLOW(urb_ring, rp)) {
         rc = urb_ring->rsp_prod_pvt;
         xen_pv_printf(&usbif->xendev, 0, "domU provided bogus ring requests "
                       "(%#x - %#x = %u). Halting ring processing.\n",
                       rp, rc, rp - rc);
         usbif->ring_error = true;
         return;
     }
 
     while (rc != rp) {
         if (RING_REQUEST_CONS_OVERFLOW(urb_ring, rc)) {
             break;
         }
         usbback_req = usbback_get_req(usbif);
 
         RING_COPY_REQUEST(urb_ring, rc, &usbback_req->req);
         usbback_req->usbif = usbif;
 
         usbback_dispatch(usbback_req);
 
         urb_ring->req_cons = ++rc;
     }
 
     RING_FINAL_CHECK_FOR_REQUESTS(urb_ring, more_to_do);
     if (more_to_do) {
         qemu_bh_schedule(usbif->bh);
     }
 }
 
 static void usbback_hotplug_enq(struct usbback_info *usbif, unsigned port)
 {
     struct usbback_hotplug *usb_hp;
 
     usb_hp = g_new0(struct usbback_hotplug, 1);
     usb_hp->port = port;
     QSIMPLEQ_INSERT_TAIL(&usbif->hotplug_q, usb_hp, q);
     usbback_hotplug_notify(usbif);
 }
 
 static void usbback_portid_drain(struct usbback_info *usbif, unsigned port)
 {
     struct usbback_req *req, *tmp;
     bool sched = false;
 
     QTAILQ_FOREACH_SAFE(req, &usbif->ports[port - 1].submit_q, q, tmp) {
         usbback_cancel_req(req);
         sched = true;
     }
 
     if (sched) {
         qemu_bh_schedule(usbif->bh);
     }
 }
 
 static void usbback_portid_detach(struct usbback_info *usbif, unsigned port)
 {
     if (!usbif->ports[port - 1].attached) {
         return;
     }
 
     usbif->ports[port - 1].speed = USBIF_SPEED_NONE;
     usbif->ports[port - 1].attached = false;
     usbback_portid_drain(usbif, port);
     usbback_hotplug_enq(usbif, port);
 }
 
 static void usbback_portid_remove(struct usbback_info *usbif, unsigned port)
 {
     if (!usbif->ports[port - 1].dev) {
         return;
     }
 
     object_unparent(OBJECT(usbif->ports[port - 1].dev));
     usbif->ports[port - 1].dev = NULL;
     usbback_portid_detach(usbif, port);
 
     TR_BUS(&usbif->xendev, "port %d removed\n", port);
 }
 
 static void usbback_portid_add(struct usbback_info *usbif, unsigned port,
                                char *busid)
 {
     unsigned speed;
     char *portname;
     Error *local_err = NULL;
     QDict *qdict;
     QemuOpts *opts;
     char *tmp;
 
     if (usbif->ports[port - 1].dev) {
         return;
     }
 
     portname = strchr(busid, '-');
     if (!portname) {
         xen_pv_printf(&usbif->xendev, 0, "device %s illegal specification\n",
                       busid);
         return;
     }
     portname++;
 
     qdict = qdict_new();
     qdict_put_str(qdict, "driver", "usb-host");
     tmp = g_strdup_printf("%s.0", usbif->xendev.qdev.id);
     qdict_put_str(qdict, "bus", tmp);
     g_free(tmp);
     tmp = g_strdup_printf("%s-%u", usbif->xendev.qdev.id, port);
     qdict_put_str(qdict, "id", tmp);
     g_free(tmp);
     qdict_put_int(qdict, "port", port);
     qdict_put_int(qdict, "hostbus", atoi(busid));
     qdict_put_str(qdict, "hostport", portname);
     opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict,
                                 &error_abort);
     usbif->ports[port - 1].dev = USB_DEVICE(qdev_device_add(opts, &local_err));
     if (!usbif->ports[port - 1].dev) {
         qobject_unref(qdict);
         xen_pv_printf(&usbif->xendev, 0,
                       "device %s could not be opened: %s\n",
                       busid, error_get_pretty(local_err));
         error_free(local_err);
         return;
     }
     qobject_unref(qdict);
     speed = usbif->ports[port - 1].dev->speed;
     switch (speed) {
     case USB_SPEED_LOW:
         speed = USBIF_SPEED_LOW;
         break;
     case USB_SPEED_FULL:
         speed = USBIF_SPEED_FULL;
         break;
     case USB_SPEED_HIGH:
         speed = (usbif->usb_ver < USB_VER_USB20) ?
                 USBIF_SPEED_NONE : USBIF_SPEED_HIGH;
         break;
     default:
         speed = USBIF_SPEED_NONE;
         break;
     }
     if (speed == USBIF_SPEED_NONE) {
         xen_pv_printf(&usbif->xendev, 0, "device %s wrong speed\n", busid);
         object_unparent(OBJECT(usbif->ports[port - 1].dev));
         usbif->ports[port - 1].dev = NULL;
         return;
     }
     usb_device_reset(usbif->ports[port - 1].dev);
     usbif->ports[port - 1].speed = speed;
     usbif->ports[port - 1].attached = true;
     QTAILQ_INIT(&usbif->ports[port - 1].submit_q);
     usbback_hotplug_enq(usbif, port);
 
     TR_BUS(&usbif->xendev, "port %d attached\n", port);
 }
 
 static void usbback_process_port(struct usbback_info *usbif, unsigned port)
 {
     char node[8];
     char *busid;
 
     snprintf(node, sizeof(node), "port/%d", port);
     busid = xenstore_read_be_str(&usbif->xendev, node);
     if (busid == NULL) {
         xen_pv_printf(&usbif->xendev, 0, "xenstore_read %s failed\n", node);
         return;
     }
 
     /* Remove portid, if the port is not connected.  */
     if (strlen(busid) == 0) {
         usbback_portid_remove(usbif, port);
     } else {
         usbback_portid_add(usbif, port, busid);
     }
 
     g_free(busid);
 }
 
 static void usbback_disconnect(struct XenLegacyDevice *xendev)
 {
     struct usbback_info *usbif;
     unsigned int i;
 
     TR_BUS(xendev, "start\n");
 
     usbif = container_of(xendev, struct usbback_info, xendev);
 
     xen_pv_unbind_evtchn(xendev);
 
     if (usbif->urb_sring) {
         xen_be_unmap_grant_ref(xendev, usbif->urb_sring);
         usbif->urb_sring = NULL;
     }
     if (usbif->conn_sring) {
         xen_be_unmap_grant_ref(xendev, usbif->conn_sring);
         usbif->conn_sring = NULL;
     }
 
     for (i = 0; i < usbif->num_ports; i++) {
         if (usbif->ports[i].dev) {
             usbback_portid_drain(usbif, i + 1);
         }
     }
 
     TR_BUS(xendev, "finished\n");
 }
 
 static int usbback_connect(struct XenLegacyDevice *xendev)
 {
     struct usbback_info *usbif;
     struct usbif_urb_sring *urb_sring;
     struct usbif_conn_sring *conn_sring;
     int urb_ring_ref;
     int conn_ring_ref;
     unsigned int i, max_grants;
 
     TR_BUS(xendev, "start\n");
 
     /* max_grants: for each request and for the rings (request and connect). */
     max_grants = USBIF_MAX_SEGMENTS_PER_REQUEST * USB_URB_RING_SIZE + 2;
     xen_be_set_max_grant_refs(xendev, max_grants);
 
     usbif = container_of(xendev, struct usbback_info, xendev);
 
     if (xenstore_read_fe_int(xendev, "urb-ring-ref", &urb_ring_ref)) {
         xen_pv_printf(xendev, 0, "error reading urb-ring-ref\n");
         return -1;
     }
     if (xenstore_read_fe_int(xendev, "conn-ring-ref", &conn_ring_ref)) {
         xen_pv_printf(xendev, 0, "error reading conn-ring-ref\n");
         return -1;
     }
     if (xenstore_read_fe_int(xendev, "event-channel", &xendev->remote_port)) {
         xen_pv_printf(xendev, 0, "error reading event-channel\n");
         return -1;
     }
 
     usbif->urb_sring = xen_be_map_grant_ref(xendev, urb_ring_ref,
                                             PROT_READ | PROT_WRITE);
     usbif->conn_sring = xen_be_map_grant_ref(xendev, conn_ring_ref,
                                              PROT_READ | PROT_WRITE);
     if (!usbif->urb_sring || !usbif->conn_sring) {
         xen_pv_printf(xendev, 0, "error mapping rings\n");
         usbback_disconnect(xendev);
         return -1;
     }
 
     urb_sring = usbif->urb_sring;
     conn_sring = usbif->conn_sring;
     BACK_RING_INIT(&usbif->urb_ring, urb_sring, XC_PAGE_SIZE);
     BACK_RING_INIT(&usbif->conn_ring, conn_sring, XC_PAGE_SIZE);
 
     xen_be_bind_evtchn(xendev);
 
     xen_pv_printf(xendev, 1, "urb-ring-ref %d, conn-ring-ref %d, "
                   "remote port %d, local port %d\n", urb_ring_ref,
                   conn_ring_ref, xendev->remote_port, xendev->local_port);
 
     for (i = 1; i <= usbif->num_ports; i++) {
         if (usbif->ports[i - 1].dev) {
             usbback_hotplug_enq(usbif, i);
         }
     }
 
     return 0;
 }
 
 static void usbback_backend_changed(struct XenLegacyDevice *xendev,
                                     const char *node)
 {
     struct usbback_info *usbif;
     unsigned int i;
 
     TR_BUS(xendev, "path %s\n", node);
 
     usbif = container_of(xendev, struct usbback_info, xendev);
     for (i = 1; i <= usbif->num_ports; i++) {
         usbback_process_port(usbif, i);
     }
 }
 
 static int usbback_init(struct XenLegacyDevice *xendev)
 {
     struct usbback_info *usbif;
 
     TR_BUS(xendev, "start\n");
 
     usbif = container_of(xendev, struct usbback_info, xendev);
 
     if (xenstore_read_be_int(xendev, "num-ports", &usbif->num_ports) ||
         usbif->num_ports < 1 || usbif->num_ports > USBBACK_MAXPORTS) {
         xen_pv_printf(xendev, 0, "num-ports not readable or out of bounds\n");
         return -1;
     }
     if (xenstore_read_be_int(xendev, "usb-ver", &usbif->usb_ver) ||
         (usbif->usb_ver != USB_VER_USB11 && usbif->usb_ver != USB_VER_USB20)) {
         xen_pv_printf(xendev, 0, "usb-ver not readable or out of bounds\n");
         return -1;
     }
 
     usbback_backend_changed(xendev, "port");
 
     TR_BUS(xendev, "finished\n");
 
     return 0;
 }
 
 static void xen_bus_attach(USBPort *port)
 {
     struct usbback_info *usbif;
 
     usbif = port->opaque;
     TR_BUS(&usbif->xendev, "\n");
     usbif->ports[port->index].attached = true;
     usbback_hotplug_enq(usbif, port->index + 1);
 }
 
 static void xen_bus_detach(USBPort *port)
 {
     struct usbback_info *usbif;
 
     usbif = port->opaque;
     TR_BUS(&usbif->xendev, "\n");
     usbback_portid_detach(usbif, port->index + 1);
 }
 
 static void xen_bus_child_detach(USBPort *port, USBDevice *child)
 {
     struct usbback_info *usbif;
 
     usbif = port->opaque;
     TR_BUS(&usbif->xendev, "\n");
 }
 
 static void xen_bus_complete(USBPort *port, USBPacket *packet)
 {
     struct usbback_req *usbback_req;
     struct usbback_info *usbif;
 
     usbback_req = container_of(packet, struct usbback_req, packet);
     if (usbback_req->cancelled) {
         g_free(usbback_req);
         return;
     }
 
     usbif = usbback_req->usbif;
     TR_REQ(&usbif->xendev, "\n");
     usbback_packet_complete(usbback_req);
 }
 
 static USBPortOps xen_usb_port_ops = {
     .attach = xen_bus_attach,
     .detach = xen_bus_detach,
     .child_detach = xen_bus_child_detach,
     .complete = xen_bus_complete,
 };
 
 static USBBusOps xen_usb_bus_ops = {
 };
 
 static void usbback_alloc(struct XenLegacyDevice *xendev)
 {
     struct usbback_info *usbif;
     USBPort *p;
     unsigned int i;
 
     usbif = container_of(xendev, struct usbback_info, xendev);
 
     usb_bus_new(&usbif->bus, sizeof(usbif->bus), &xen_usb_bus_ops,
                 DEVICE(&xendev->qdev));
     for (i = 0; i < USBBACK_MAXPORTS; i++) {
         p = &(usbif->ports[i].port);
         usb_register_port(&usbif->bus, p, usbif, i, &xen_usb_port_ops,
                           USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL |
                           USB_SPEED_MASK_HIGH);
     }
 
     QTAILQ_INIT(&usbif->req_free_q);
     QSIMPLEQ_INIT(&usbif->hotplug_q);
     usbif->bh = qemu_bh_new(usbback_bh, usbif);
 }
 
 static int usbback_free(struct XenLegacyDevice *xendev)
 {
     struct usbback_info *usbif;
     struct usbback_req *usbback_req;
     struct usbback_hotplug *usb_hp;
     unsigned int i;
 
     TR_BUS(xendev, "start\n");
 
     usbback_disconnect(xendev);
     usbif = container_of(xendev, struct usbback_info, xendev);
     for (i = 1; i <= usbif->num_ports; i++) {
         usbback_portid_remove(usbif, i);
     }
 
     while (!QTAILQ_EMPTY(&usbif->req_free_q)) {
         usbback_req = QTAILQ_FIRST(&usbif->req_free_q);
         QTAILQ_REMOVE(&usbif->req_free_q, usbback_req, q);
         g_free(usbback_req);
     }
     while (!QSIMPLEQ_EMPTY(&usbif->hotplug_q)) {
         usb_hp = QSIMPLEQ_FIRST(&usbif->hotplug_q);
         QSIMPLEQ_REMOVE_HEAD(&usbif->hotplug_q, q);
         g_free(usb_hp);
     }
 
     qemu_bh_delete(usbif->bh);
 
     for (i = 0; i < USBBACK_MAXPORTS; i++) {
         usb_unregister_port(&usbif->bus, &(usbif->ports[i].port));
     }
 
     usb_bus_release(&usbif->bus);
 
     TR_BUS(xendev, "finished\n");
 
     return 0;
 }
 
 static void usbback_event(struct XenLegacyDevice *xendev)
 {
     struct usbback_info *usbif;
 
     usbif = container_of(xendev, struct usbback_info, xendev);
     qemu_bh_schedule(usbif->bh);
 }
 
 struct XenDevOps xen_usb_ops = {
     .size            = sizeof(struct usbback_info),
     .flags           = DEVOPS_FLAG_NEED_GNTDEV,
     .init            = usbback_init,
     .alloc           = usbback_alloc,
     .free            = usbback_free,
     .backend_changed = usbback_backend_changed,
     .initialise      = usbback_connect,
     .disconnect      = usbback_disconnect,
     .event           = usbback_event,
 };
 
 #else /* USBIF_SHORT_NOT_OK */
 
 static int usbback_not_supported(void)
 {
     return -EINVAL;
 }
 
 struct XenDevOps xen_usb_ops = {
     .backend_register = usbback_not_supported,
 };
 
 #endif