Implement the probe function for the pvcalls frontend. Read the
supported versions, max-page-order and function-calls nodes from
xenstore.
Only one frontend<->backend connection is supported at any given time
for a guest. Store the active frontend device to a static pointer.
Introduce a stub functions for the event handler.
Signed-off-by: Stefano Stabellini
CC: boris.ostrov...@oracle.com
CC: jgr...@suse.com
---
drivers/xen/pvcalls-front.c | 133
1 file changed, 133 insertions(+)
diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 67c8337..ffbbcd1 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -96,12 +96,145 @@ 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);
+ INIT_LIST_HEAD(&bedata->socketpass_mappings);
+ spin_lock_init(&bedata->socket_lock);
+ bedata->irq = -1;
+ bedata->ref = -1;
+
+ for (i = 0; i < PVCALLS_NR_REQ_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,
