diff options
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/pvcalls-front.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index aae23d046967..1618502c1c66 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -104,12 +104,144 @@ static int pvcalls_front_remove(struct xenbus_device *dev) static int pvcalls_front_probe(struct xenbus_device *dev, const struct xenbus_device_id *id) { + int ret = -ENOMEM, evtchn, i; + unsigned int max_page_order, function_calls, len; + char *versions; + grant_ref_t gref_head = 0; + struct xenbus_transaction xbt; + struct pvcalls_bedata *bedata = NULL; + struct xen_pvcalls_sring *sring; + + if (pvcalls_front_dev != NULL) { + dev_err(&dev->dev, "only one PV Calls connection supported\n"); + return -EINVAL; + } + + versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len); + if (!len) + return -EINVAL; + if (strcmp(versions, "1")) { + kfree(versions); + return -EINVAL; + } + kfree(versions); + max_page_order = xenbus_read_unsigned(dev->otherend, + "max-page-order", 0); + if (max_page_order < PVCALLS_RING_ORDER) + return -ENODEV; + function_calls = xenbus_read_unsigned(dev->otherend, + "function-calls", 0); + /* See XENBUS_FUNCTIONS_CALLS in pvcalls.h */ + if (function_calls != 1) + return -ENODEV; + pr_info("%s max-page-order is %u\n", __func__, max_page_order); + + bedata = kzalloc(sizeof(struct pvcalls_bedata), GFP_KERNEL); + if (!bedata) + return -ENOMEM; + + dev_set_drvdata(&dev->dev, bedata); + pvcalls_front_dev = dev; + init_waitqueue_head(&bedata->inflight_req); + INIT_LIST_HEAD(&bedata->socket_mappings); + spin_lock_init(&bedata->socket_lock); + bedata->irq = -1; + bedata->ref = -1; + + for (i = 0; i < PVCALLS_NR_RSP_PER_RING; i++) + bedata->rsp[i].req_id = PVCALLS_INVALID_ID; + + sring = (struct xen_pvcalls_sring *) __get_free_page(GFP_KERNEL | + __GFP_ZERO); + if (!sring) + goto error; + SHARED_RING_INIT(sring); + FRONT_RING_INIT(&bedata->ring, sring, XEN_PAGE_SIZE); + + ret = xenbus_alloc_evtchn(dev, &evtchn); + if (ret) + goto error; + + bedata->irq = bind_evtchn_to_irqhandler(evtchn, + pvcalls_front_event_handler, + 0, "pvcalls-frontend", dev); + if (bedata->irq < 0) { + ret = bedata->irq; + goto error; + } + + ret = gnttab_alloc_grant_references(1, &gref_head); + if (ret < 0) + goto error; + bedata->ref = gnttab_claim_grant_reference(&gref_head); + if (bedata->ref < 0) { + ret = bedata->ref; + goto error; + } + gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id, + virt_to_gfn((void *)sring), 0); + + again: + ret = xenbus_transaction_start(&xbt); + if (ret) { + xenbus_dev_fatal(dev, ret, "starting transaction"); + goto error; + } + ret = xenbus_printf(xbt, dev->nodename, "version", "%u", 1); + if (ret) + goto error_xenbus; + ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", bedata->ref); + if (ret) + goto error_xenbus; + ret = xenbus_printf(xbt, dev->nodename, "port", "%u", + evtchn); + if (ret) + goto error_xenbus; + ret = xenbus_transaction_end(xbt, 0); + if (ret) { + if (ret == -EAGAIN) + goto again; + xenbus_dev_fatal(dev, ret, "completing transaction"); + goto error; + } + xenbus_switch_state(dev, XenbusStateInitialised); + return 0; + + error_xenbus: + xenbus_transaction_end(xbt, 1); + xenbus_dev_fatal(dev, ret, "writing xenstore"); + error: + pvcalls_front_remove(dev); + return ret; } static void pvcalls_front_changed(struct xenbus_device *dev, enum xenbus_state backend_state) { + switch (backend_state) { + case XenbusStateReconfiguring: + case XenbusStateReconfigured: + case XenbusStateInitialising: + case XenbusStateInitialised: + case XenbusStateUnknown: + break; + + case XenbusStateInitWait: + break; + + case XenbusStateConnected: + xenbus_switch_state(dev, XenbusStateConnected); + break; + + case XenbusStateClosed: + if (dev->state == XenbusStateClosed) + break; + /* Missed the backend's CLOSING state -- fallthrough */ + case XenbusStateClosing: + xenbus_frontend_closed(dev); + break; + } } static struct xenbus_driver pvcalls_front_driver = { |