xen-netback: add control ring boilerplate
My recent patch to include/xen/interface/io/netif.h defines a new shared
ring (in addition to the rx and tx rings) for passing control messages
from a VM frontend driver to a backend driver.
This patch adds the necessary code to xen-netback to map this new shared
ring, should it be created by a frontend, but does not add implementations
for any of the defined protocol messages. These are added in a subsequent
patch for clarity.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index bd182cd..6a31f26 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -38,7 +38,8 @@
const char *hotplug_script;
};
-static int connect_rings(struct backend_info *be, struct xenvif_queue *queue);
+static int connect_data_rings(struct backend_info *be,
+ struct xenvif_queue *queue);
static void connect(struct backend_info *be);
static int read_xenbus_vif_flags(struct backend_info *be);
static int backend_create_xenvif(struct backend_info *be);
@@ -367,6 +368,12 @@
if (err)
pr_debug("Error writing multi-queue-max-queues\n");
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "feature-ctrl-ring",
+ "%u", true);
+ if (err)
+ pr_debug("Error writing feature-ctrl-ring\n");
+
script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
if (IS_ERR(script)) {
err = PTR_ERR(script);
@@ -457,7 +464,8 @@
#ifdef CONFIG_DEBUG_FS
xenvif_debugfs_delif(be->vif);
#endif /* CONFIG_DEBUG_FS */
- xenvif_disconnect(be->vif);
+ xenvif_disconnect_data(be->vif);
+ xenvif_disconnect_ctrl(be->vif);
}
}
@@ -825,6 +833,48 @@
kfree(str);
}
+static int connect_ctrl_ring(struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ struct xenvif *vif = be->vif;
+ unsigned int val;
+ grant_ref_t ring_ref;
+ unsigned int evtchn;
+ int err;
+
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "ctrl-ring-ref", "%u", &val, NULL);
+ if (err)
+ goto done; /* The frontend does not have a control ring */
+
+ ring_ref = val;
+
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "event-channel-ctrl", "%u", &val, NULL);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "reading %s/event-channel-ctrl",
+ dev->otherend);
+ goto fail;
+ }
+
+ evtchn = val;
+
+ err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "mapping shared-frame %u port %u",
+ ring_ref, evtchn);
+ goto fail;
+ }
+
+done:
+ return 0;
+
+fail:
+ return err;
+}
+
static void connect(struct backend_info *be)
{
int err;
@@ -861,6 +911,12 @@
xen_register_watchers(dev, be->vif);
read_xenbus_vif_flags(be);
+ err = connect_ctrl_ring(be);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "connecting control ring");
+ return;
+ }
+
/* Use the number of queues requested by the frontend */
be->vif->queues = vzalloc(requested_num_queues *
sizeof(struct xenvif_queue));
@@ -896,11 +952,12 @@
queue->remaining_credit = credit_bytes;
queue->credit_usec = credit_usec;
- err = connect_rings(be, queue);
+ err = connect_data_rings(be, queue);
if (err) {
- /* connect_rings() cleans up after itself on failure,
- * but we need to clean up after xenvif_init_queue() here,
- * and also clean up any previously initialised queues.
+ /* connect_data_rings() cleans up after itself on
+ * failure, but we need to clean up after
+ * xenvif_init_queue() here, and also clean up any
+ * previously initialised queues.
*/
xenvif_deinit_queue(queue);
be->vif->num_queues = queue_index;
@@ -935,15 +992,17 @@
err:
if (be->vif->num_queues > 0)
- xenvif_disconnect(be->vif); /* Clean up existing queues */
+ xenvif_disconnect_data(be->vif); /* Clean up existing queues */
vfree(be->vif->queues);
be->vif->queues = NULL;
be->vif->num_queues = 0;
+ xenvif_disconnect_ctrl(be->vif);
return;
}
-static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
+static int connect_data_rings(struct backend_info *be,
+ struct xenvif_queue *queue)
{
struct xenbus_device *dev = be->dev;
unsigned int num_queues = queue->vif->num_queues;
@@ -1007,8 +1066,8 @@
}
/* Map the shared frame, irq etc. */
- err = xenvif_connect(queue, tx_ring_ref, rx_ring_ref,
- tx_evtchn, rx_evtchn);
+ err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
+ tx_evtchn, rx_evtchn);
if (err) {
xenbus_dev_fatal(dev, err,
"mapping shared-frames %lu/%lu port tx %u rx %u",