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-rw-r--r--drivers/net/xen-netback/common.h2
-rw-r--r--drivers/net/xen-netback/interface.c23
-rw-r--r--drivers/net/xen-netback/netback.c8
-rw-r--r--drivers/net/xen-netback/xenbus.c101
4 files changed, 116 insertions, 18 deletions
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index b6885cfcc7df..4dd7c4a1923b 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -237,6 +237,7 @@ struct xenvif *xenvif_alloc(struct device *parent,
unsigned int handle);
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,
@@ -299,5 +300,6 @@ extern bool separate_tx_rx_irq;
extern unsigned int rx_drain_timeout_msecs;
extern unsigned int rx_drain_timeout_jiffies;
+extern unsigned int xenvif_max_queues;
#endif /* __XEN_NETBACK__COMMON_H__ */
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 6005b5d1d404..6929bcb61cf0 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -139,7 +139,6 @@ static void xenvif_wake_queue_callback(unsigned long data)
static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
void *accel_priv, select_queue_fallback_t fallback)
{
- struct xenvif *vif = netdev_priv(dev);
unsigned int num_queues = dev->real_num_tx_queues;
u32 hash;
u16 queue_index;
@@ -436,7 +435,12 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
char name[IFNAMSIZ] = {};
snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
- dev = alloc_netdev_mq(sizeof(struct xenvif), name, ether_setup, 1);
+ /* Allocate a netdev with the max. supported number of queues.
+ * When the guest selects the desired number, it will be updated
+ * via netif_set_real_num_tx_queues().
+ */
+ dev = alloc_netdev_mq(sizeof(struct xenvif), name, ether_setup,
+ xenvif_max_queues);
if (dev == NULL) {
pr_warn("Could not allocate netdev for %s\n", name);
return ERR_PTR(-ENOMEM);
@@ -706,6 +710,16 @@ void xenvif_disconnect(struct xenvif *vif)
}
}
+/* 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().
+ */
+void xenvif_deinit_queue(struct xenvif_queue *queue)
+{
+ free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
+ netif_napi_del(&queue->napi);
+}
+
void xenvif_free(struct xenvif *vif)
{
struct xenvif_queue *queue = NULL;
@@ -729,11 +743,8 @@ void xenvif_free(struct xenvif *vif)
for (queue_index = 0; queue_index < num_queues; ++queue_index) {
queue = &vif->queues[queue_index];
-
xenvif_wait_unmap_timeout(queue, worst_case_skb_lifetime);
- free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
-
- netif_napi_del(&queue->napi);
+ xenvif_deinit_queue(queue);
}
/* Free the array of queues. The call below does not require
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index a5484e8cb06e..49efff9b99f4 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -62,6 +62,11 @@ unsigned int rx_drain_timeout_msecs = 10000;
module_param(rx_drain_timeout_msecs, uint, 0444);
unsigned int rx_drain_timeout_jiffies;
+unsigned int xenvif_max_queues;
+module_param_named(max_queues, xenvif_max_queues, uint, 0644);
+MODULE_PARM_DESC(max_queues,
+ "Maximum number of queues per virtual interface");
+
/*
* This is the maximum slots a skb can have. If a guest sends a skb
* which exceeds this limit it is considered malicious.
@@ -1953,6 +1958,9 @@ static int __init netback_init(void)
if (!xen_domain())
return -ENODEV;
+ /* Allow as many queues as there are CPUs, by default */
+ xenvif_max_queues = num_online_cpus();
+
if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 358602f55afa..96c63dc2509e 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -160,6 +160,12 @@ static int netback_probe(struct xenbus_device *dev,
if (err)
pr_debug("Error writing feature-split-event-channels\n");
+ /* Multi-queue support: This is an optional feature. */
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "multi-queue-max-queues", "%u", xenvif_max_queues);
+ if (err)
+ pr_debug("Error writing multi-queue-max-queues\n");
+
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
@@ -490,9 +496,25 @@ static void connect(struct backend_info *be)
struct xenbus_device *dev = be->dev;
unsigned long credit_bytes, credit_usec;
unsigned int queue_index;
- unsigned int requested_num_queues = 1;
+ unsigned int requested_num_queues;
struct xenvif_queue *queue;
+ /* Check whether the frontend requested multiple queues
+ * and read the number requested.
+ */
+ err = xenbus_scanf(XBT_NIL, dev->otherend,
+ "multi-queue-num-queues",
+ "%u", &requested_num_queues);
+ if (err < 0) {
+ requested_num_queues = 1; /* Fall back to single queue */
+ } else if (requested_num_queues > xenvif_max_queues) {
+ /* buggy or malicious guest */
+ xenbus_dev_fatal(dev, err,
+ "guest requested %u queues, exceeding the maximum of %u.",
+ requested_num_queues, xenvif_max_queues);
+ return;
+ }
+
err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
if (err) {
xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
@@ -502,6 +524,7 @@ static void connect(struct backend_info *be)
xen_net_read_rate(dev, &credit_bytes, &credit_usec);
read_xenbus_vif_flags(be);
+ /* Use the number of queues requested by the frontend */
be->vif->queues = vzalloc(requested_num_queues *
sizeof(struct xenvif_queue));
rtnl_lock();
@@ -516,14 +539,33 @@ static void connect(struct backend_info *be)
be->vif->dev->name, queue->id);
err = xenvif_init_queue(queue);
- if (err)
+ if (err) {
+ /* xenvif_init_queue() cleans up after itself on
+ * failure, but we need to clean up any previously
+ * initialised queues. Set num_queues to i so that
+ * earlier queues can be destroyed using the regular
+ * disconnect logic.
+ */
+ rtnl_lock();
+ netif_set_real_num_tx_queues(be->vif->dev, queue_index);
+ rtnl_unlock();
goto err;
+ }
queue->remaining_credit = credit_bytes;
err = connect_rings(be, queue);
- if (err)
+ 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.
+ */
+ xenvif_deinit_queue(queue);
+ rtnl_lock();
+ netif_set_real_num_tx_queues(be->vif->dev, queue_index);
+ rtnl_unlock();
goto err;
+ }
}
xenvif_carrier_on(be->vif);
@@ -540,6 +582,8 @@ static void connect(struct backend_info *be)
return;
err:
+ if (be->vif->dev->real_num_tx_queues > 0)
+ xenvif_disconnect(be->vif); /* Clean up existing queues */
vfree(be->vif->queues);
be->vif->queues = NULL;
rtnl_lock();
@@ -552,32 +596,62 @@ err:
static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
{
struct xenbus_device *dev = be->dev;
+ unsigned int num_queues = queue->vif->dev->real_num_tx_queues;
unsigned long tx_ring_ref, rx_ring_ref;
unsigned int tx_evtchn, rx_evtchn;
int err;
+ char *xspath;
+ size_t xspathsize;
+ const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
+
+ /* If the frontend requested 1 queue, or we have fallen back
+ * to single queue due to lack of frontend support for multi-
+ * queue, expect the remaining XenStore keys in the toplevel
+ * directory. Otherwise, expect them in a subdirectory called
+ * queue-N.
+ */
+ if (num_queues == 1) {
+ xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
+ if (!xspath) {
+ xenbus_dev_fatal(dev, -ENOMEM,
+ "reading ring references");
+ return -ENOMEM;
+ }
+ strcpy(xspath, dev->otherend);
+ } else {
+ xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
+ xspath = kzalloc(xspathsize, GFP_KERNEL);
+ if (!xspath) {
+ xenbus_dev_fatal(dev, -ENOMEM,
+ "reading ring references");
+ return -ENOMEM;
+ }
+ snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend,
+ queue->id);
+ }
- err = xenbus_gather(XBT_NIL, dev->otherend,
+ err = xenbus_gather(XBT_NIL, xspath,
"tx-ring-ref", "%lu", &tx_ring_ref,
"rx-ring-ref", "%lu", &rx_ring_ref, NULL);
if (err) {
xenbus_dev_fatal(dev, err,
"reading %s/ring-ref",
- dev->otherend);
- return err;
+ xspath);
+ goto err;
}
/* Try split event channels first, then single event channel. */
- err = xenbus_gather(XBT_NIL, dev->otherend,
+ err = xenbus_gather(XBT_NIL, xspath,
"event-channel-tx", "%u", &tx_evtchn,
"event-channel-rx", "%u", &rx_evtchn, NULL);
if (err < 0) {
- err = xenbus_scanf(XBT_NIL, dev->otherend,
+ err = xenbus_scanf(XBT_NIL, xspath,
"event-channel", "%u", &tx_evtchn);
if (err < 0) {
xenbus_dev_fatal(dev, err,
"reading %s/event-channel(-tx/rx)",
- dev->otherend);
- return err;
+ xspath);
+ goto err;
}
rx_evtchn = tx_evtchn;
}
@@ -590,10 +664,13 @@ static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
"mapping shared-frames %lu/%lu port tx %u rx %u",
tx_ring_ref, rx_ring_ref,
tx_evtchn, rx_evtchn);
- return err;
+ goto err;
}
- return 0;
+ err = 0;
+err: /* Regular return falls through with err == 0 */
+ kfree(xspath);
+ return err;
}
static int read_xenbus_vif_flags(struct backend_info *be)