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xen-netback: add control ring boilerplate

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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>
This commit is contained in:
Paul Durrant
2016-05-13 09:37:26 +01:00
committed by David S. Miller
parent 1ca4673432
commit 4e15ee2cb4
4 changed files with 277 additions and 30 deletions
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101
drivers/net/xen-netback/interface.c
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@@ -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().