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 <[email protected]>
Acked-by: Wei Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 4412a57..ff22b6d 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1926,7 +1926,7 @@
return queue->dealloc_cons != queue->dealloc_prod;
}
-void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
+void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
{
if (queue->tx.sring)
xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
@@ -1936,9 +1936,9 @@
queue->rx.sring);
}
-int xenvif_map_frontend_rings(struct xenvif_queue *queue,
- grant_ref_t tx_ring_ref,
- grant_ref_t rx_ring_ref)
+int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
+ grant_ref_t tx_ring_ref,
+ grant_ref_t rx_ring_ref)
{
void *addr;
struct xen_netif_tx_sring *txs;
@@ -1965,7 +1965,7 @@
return 0;
err:
- xenvif_unmap_frontend_rings(queue);
+ xenvif_unmap_frontend_data_rings(queue);
return err;
}
@@ -2164,6 +2164,95 @@
return 0;
}
+static void make_ctrl_response(struct xenvif *vif,
+ const struct xen_netif_ctrl_request *req,
+ u32 status, u32 data)
+{
+ RING_IDX idx = vif->ctrl.rsp_prod_pvt;
+ struct xen_netif_ctrl_response rsp = {
+ .id = req->id,
+ .type = req->type,
+ .status = status,
+ .data = data,
+ };
+
+ *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
+ vif->ctrl.rsp_prod_pvt = ++idx;
+}
+
+static void push_ctrl_response(struct xenvif *vif)
+{
+ int notify;
+
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
+ if (notify)
+ notify_remote_via_irq(vif->ctrl_irq);
+}
+
+static void process_ctrl_request(struct xenvif *vif,
+ const struct xen_netif_ctrl_request *req)
+{
+ make_ctrl_response(vif, req, XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED,
+ 0);
+ push_ctrl_response(vif);
+}
+
+static void xenvif_ctrl_action(struct xenvif *vif)
+{
+ for (;;) {
+ RING_IDX req_prod, req_cons;
+
+ req_prod = vif->ctrl.sring->req_prod;
+ req_cons = vif->ctrl.req_cons;
+
+ /* Make sure we can see requests before we process them. */
+ rmb();
+
+ if (req_cons == req_prod)
+ break;
+
+ while (req_cons != req_prod) {
+ struct xen_netif_ctrl_request req;
+
+ RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
+ req_cons++;
+
+ process_ctrl_request(vif, &req);
+ }
+
+ vif->ctrl.req_cons = req_cons;
+ vif->ctrl.sring->req_event = req_cons + 1;
+ }
+}
+
+static bool xenvif_ctrl_work_todo(struct xenvif *vif)
+{
+ if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
+ return 1;
+
+ return 0;
+}
+
+int xenvif_ctrl_kthread(void *data)
+{
+ struct xenvif *vif = data;
+
+ for (;;) {
+ wait_event_interruptible(vif->ctrl_wq,
+ xenvif_ctrl_work_todo(vif) ||
+ kthread_should_stop());
+ if (kthread_should_stop())
+ break;
+
+ while (xenvif_ctrl_work_todo(vif))
+ xenvif_ctrl_action(vif);
+
+ cond_resched();
+ }
+
+ return 0;
+}
+
static int __init netback_init(void)
{
int rc = 0;
