Commit 21968190 authored by Stefano Stabellini's avatar Stefano Stabellini Committed by Boris Ostrovsky

xen/pvcalls: connect to the backend

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: default avatarStefano Stabellini <stefano@aporeto.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent aa7ba376
...@@ -104,12 +104,144 @@ static int pvcalls_front_remove(struct xenbus_device *dev) ...@@ -104,12 +104,144 @@ static int pvcalls_front_remove(struct xenbus_device *dev)
static int pvcalls_front_probe(struct xenbus_device *dev, static int pvcalls_front_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id) 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; 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, static void pvcalls_front_changed(struct xenbus_device *dev,
enum xenbus_state backend_state) 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 = { static struct xenbus_driver pvcalls_front_driver = {
......
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