Commit 4e15ee2c authored by Paul Durrant's avatar Paul Durrant Committed by David S. Miller

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: default avatarPaul Durrant <paul.durrant@citrix.com>
Acked-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1ca46734
......@@ -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,
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(struct xenvif *vif);
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);
......@@ -300,8 +310,8 @@ 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,
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);
......@@ -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);
......
......@@ -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;
......@@ -527,8 +536,65 @@ 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,
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;
......@@ -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 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
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().
......
......@@ -1926,7 +1926,7 @@ 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),
......@@ -1936,7 +1936,7 @@ void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
queue->rx.sring);
}
int xenvif_map_frontend_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)
{
......@@ -1965,7 +1965,7 @@ 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;
}
......@@ -2164,6 +2164,95 @@ 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;
......
......@@ -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;
......@@ -1007,7 +1066,7 @@ 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,
err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
tx_evtchn, rx_evtchn);
if (err) {
xenbus_dev_fatal(dev, err,
......
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