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Message-ID: <1462979790-2824-2-git-send-email-paul.durrant@citrix.com>
Date: Wed, 11 May 2016 16:16:27 +0100
From: Paul Durrant <paul.durrant@...rix.com>
To: <xen-devel@...ts.xenproject.org>, <netdev@...r.kernel.org>
CC: Paul Durrant <paul.durrant@...rix.com>,
Wei Liu <wei.liu2@...rix.com>
Subject: [PATCH net-next v2 1/4] 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@...rix.com>
Cc: Wei Liu <wei.liu2@...rix.com>
---
v2:
- Changed error handling style in connect_ctrl_ring()
---
drivers/net/xen-netback/common.h | 28 +++++++---
drivers/net/xen-netback/interface.c | 101 +++++++++++++++++++++++++++++++++---
drivers/net/xen-netback/netback.c | 99 +++++++++++++++++++++++++++++++++--
drivers/net/xen-netback/xenbus.c | 79 ++++++++++++++++++++++++----
4 files changed, 277 insertions(+), 30 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index f44b388..093a12a 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -260,6 +260,11 @@ struct xenvif {
struct dentry *xenvif_dbg_root;
#endif
+ struct xen_netif_ctrl_back_ring ctrl;
+ struct task_struct *ctrl_task;
+ wait_queue_head_t ctrl_wq;
+ unsigned int ctrl_irq;
+
/* Miscellaneous private stuff. */
struct net_device *dev;
};
@@ -285,10 +290,15 @@ struct xenvif *xenvif_alloc(struct device *parent,
int xenvif_init_queue(struct xenvif_queue *queue);
void xenvif_deinit_queue(struct xenvif_queue *queue);
-int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
- unsigned long rx_ring_ref, unsigned int tx_evtchn,
- unsigned int rx_evtchn);
-void xenvif_disconnect(struct xenvif *vif);
+int xenvif_connect_data(struct xenvif_queue *queue,
+ unsigned long tx_ring_ref,
+ unsigned long rx_ring_ref,
+ unsigned int tx_evtchn,
+ unsigned int rx_evtchn);
+void xenvif_disconnect_data(struct xenvif *vif);
+int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
+ unsigned int evtchn);
+void xenvif_disconnect_ctrl(struct xenvif *vif);
void xenvif_free(struct xenvif *vif);
int xenvif_xenbus_init(void);
@@ -300,10 +310,10 @@ int xenvif_queue_stopped(struct xenvif_queue *queue);
void xenvif_wake_queue(struct xenvif_queue *queue);
/* (Un)Map communication rings. */
-void xenvif_unmap_frontend_rings(struct xenvif_queue *queue);
-int xenvif_map_frontend_rings(struct xenvif_queue *queue,
- grant_ref_t tx_ring_ref,
- grant_ref_t rx_ring_ref);
+void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue);
+int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
+ grant_ref_t tx_ring_ref,
+ grant_ref_t rx_ring_ref);
/* Check for SKBs from frontend and schedule backend processing */
void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue);
@@ -318,6 +328,8 @@ void xenvif_kick_thread(struct xenvif_queue *queue);
int xenvif_dealloc_kthread(void *data);
+int xenvif_ctrl_kthread(void *data);
+
void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
void xenvif_carrier_on(struct xenvif *vif);
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index f5231a2..78a10d2 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -128,6 +128,15 @@ irqreturn_t xenvif_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
+irqreturn_t xenvif_ctrl_interrupt(int irq, void *dev_id)
+{
+ struct xenvif *vif = dev_id;
+
+ wake_up(&vif->ctrl_wq);
+
+ return IRQ_HANDLED;
+}
+
int xenvif_queue_stopped(struct xenvif_queue *queue)
{
struct net_device *dev = queue->vif->dev;
@@ -527,9 +536,66 @@ void xenvif_carrier_on(struct xenvif *vif)
rtnl_unlock();
}
-int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
- unsigned long rx_ring_ref, unsigned int tx_evtchn,
- unsigned int rx_evtchn)
+int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
+ unsigned int evtchn)
+{
+ struct net_device *dev = vif->dev;
+ void *addr;
+ struct xen_netif_ctrl_sring *shared;
+ struct task_struct *task;
+ int err = -ENOMEM;
+
+ err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+ &ring_ref, 1, &addr);
+ if (err)
+ goto err;
+
+ shared = (struct xen_netif_ctrl_sring *)addr;
+ BACK_RING_INIT(&vif->ctrl, shared, XEN_PAGE_SIZE);
+
+ init_waitqueue_head(&vif->ctrl_wq);
+
+ err = bind_interdomain_evtchn_to_irqhandler(vif->domid, evtchn,
+ xenvif_ctrl_interrupt,
+ 0, dev->name, vif);
+ if (err < 0)
+ goto err_unmap;
+
+ vif->ctrl_irq = err;
+
+ task = kthread_create(xenvif_ctrl_kthread, (void *)vif,
+ "%s-control", dev->name);
+ if (IS_ERR(task)) {
+ pr_warn("Could not allocate kthread for %s\n", dev->name);
+ err = PTR_ERR(task);
+ goto err_deinit;
+ }
+
+ get_task_struct(task);
+ vif->ctrl_task = task;
+
+ wake_up_process(vif->ctrl_task);
+
+ return 0;
+
+err_deinit:
+ unbind_from_irqhandler(vif->ctrl_irq, vif);
+ vif->ctrl_irq = 0;
+
+err_unmap:
+ xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+ vif->ctrl.sring);
+ vif->ctrl.sring = NULL;
+
+err:
+ return err;
+}
+
+int xenvif_connect_data(struct xenvif_queue *queue,
+ unsigned long tx_ring_ref,
+ unsigned long rx_ring_ref,
+ unsigned int tx_evtchn,
+ unsigned int rx_evtchn)
{
struct task_struct *task;
int err = -ENOMEM;
@@ -538,7 +604,8 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
BUG_ON(queue->task);
BUG_ON(queue->dealloc_task);
- err = xenvif_map_frontend_rings(queue, tx_ring_ref, rx_ring_ref);
+ err = xenvif_map_frontend_data_rings(queue, tx_ring_ref,
+ rx_ring_ref);
if (err < 0)
goto err;
@@ -614,7 +681,7 @@ err_tx_unbind:
unbind_from_irqhandler(queue->tx_irq, queue);
queue->tx_irq = 0;
err_unmap:
- xenvif_unmap_frontend_rings(queue);
+ xenvif_unmap_frontend_data_rings(queue);
netif_napi_del(&queue->napi);
err:
module_put(THIS_MODULE);
@@ -634,7 +701,7 @@ void xenvif_carrier_off(struct xenvif *vif)
rtnl_unlock();
}
-void xenvif_disconnect(struct xenvif *vif)
+void xenvif_disconnect_data(struct xenvif *vif)
{
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
@@ -668,12 +735,32 @@ void xenvif_disconnect(struct xenvif *vif)
queue->tx_irq = 0;
}
- xenvif_unmap_frontend_rings(queue);
+ xenvif_unmap_frontend_data_rings(queue);
}
xenvif_mcast_addr_list_free(vif);
}
+void xenvif_disconnect_ctrl(struct xenvif *vif)
+{
+ if (vif->ctrl_task) {
+ kthread_stop(vif->ctrl_task);
+ put_task_struct(vif->ctrl_task);
+ vif->ctrl_task = NULL;
+ }
+
+ if (vif->ctrl_irq) {
+ unbind_from_irqhandler(vif->ctrl_irq, vif);
+ vif->ctrl_irq = 0;
+ }
+
+ if (vif->ctrl.sring) {
+ xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+ vif->ctrl.sring);
+ vif->ctrl.sring = NULL;
+ }
+}
+
/* Reverse the relevant parts of xenvif_init_queue().
* Used for queue teardown from xenvif_free(), and on the
* error handling paths in xenbus.c:connect().
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index b42f260..45aa40b 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1925,7 +1925,7 @@ static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
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),
@@ -1935,9 +1935,9 @@ void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
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;
@@ -1964,7 +1964,7 @@ int xenvif_map_frontend_rings(struct xenvif_queue *queue,
return 0;
err:
- xenvif_unmap_frontend_rings(queue);
+ xenvif_unmap_frontend_data_rings(queue);
return err;
}
@@ -2163,6 +2163,95 @@ int xenvif_dealloc_kthread(void *data)
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;
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 @@ struct backend_info {
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 @@ static int netback_probe(struct xenbus_device *dev,
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 @@ static void backend_disconnect(struct backend_info *be)
#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 @@ static void hotplug_status_changed(struct xenbus_watch *watch,
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 @@ static void connect(struct backend_info *be)
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 @@ static void connect(struct backend_info *be)
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 @@ static void connect(struct backend_info *be)
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 @@ static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
}
/* 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",
--
2.1.4
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