hv_netvsc: Fix race between VF offering and VF association message from host

During vm boot, there might be possibility that vf registration
call comes before the vf association from host to vm.

And this might break netvsc vf path, To prevent the same block
vf registration until vf bind message comes from host.

Cc: stable@vger.kernel.org
Fixes: 00d7ddba11436 ("hv_netvsc: pair VF based on serial number")
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Gaurav Kohli <gauravkohli@linux.microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 25b38a374e3c3db8509ce34c1addf739d47f77ef..dd5919ec408bf6ec9f37d44727c9e4d19416f5d0 100644 (file)
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -1051,7 +1051,8 @@ struct net_device_context {
        u32 vf_alloc;
        /* Serial number of the VF to team with */
        u32 vf_serial;
-
+       /* completion variable to confirm vf association */
+       struct completion vf_add;
        /* Is the current data path through the VF NIC? */
        bool  data_path_is_vf;
 

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index f066de0da49254651a89aa79bd3a890f0c6acc40..9352dad58996d831e596939c94e86daf0524d9a2 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1580,6 +1580,10 @@ static void netvsc_send_vf(struct net_device *ndev,
 
        net_device_ctx->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
        net_device_ctx->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
+
+       if (net_device_ctx->vf_alloc)
+               complete(&net_device_ctx->vf_add);
+
        netdev_info(ndev, "VF slot %u %s\n",
                    net_device_ctx->vf_serial,
                    net_device_ctx->vf_alloc ? "added" : "removed");

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 5f08482065cab3d61c60f9a6e9ceb5a3ac882ecc..89eb4f179a3ceff333617a224e71e968c7ad272a 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2313,6 +2313,18 @@ static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
 
        }
 
+       /* Fallback path to check synthetic vf with
+        * help of mac addr
+        */
+       list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
+               ndev = hv_get_drvdata(ndev_ctx->device_ctx);
+               if (ether_addr_equal(vf_netdev->perm_addr, ndev->perm_addr)) {
+                       netdev_notice(vf_netdev,
+                                     "falling back to mac addr based matching\n");
+                       return ndev;
+               }
+       }
+
        netdev_notice(vf_netdev,
                      "no netdev found for vf serial:%u\n", serial);
        return NULL;
@@ -2409,6 +2421,11 @@ static int netvsc_vf_changed(struct net_device *vf_netdev, unsigned long event)
        if (net_device_ctx->data_path_is_vf == vf_is_up)
                return NOTIFY_OK;
 
+       if (vf_is_up && !net_device_ctx->vf_alloc) {
+               netdev_info(ndev, "Waiting for the VF association from host\n");
+               wait_for_completion(&net_device_ctx->vf_add);
+       }
+
        ret = netvsc_switch_datapath(ndev, vf_is_up);
 
        if (ret) {
@@ -2440,6 +2457,7 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev)
 
        netvsc_vf_setxdp(vf_netdev, NULL);
 
+       reinit_completion(&net_device_ctx->vf_add);
        netdev_rx_handler_unregister(vf_netdev);
        netdev_upper_dev_unlink(vf_netdev, ndev);
        RCU_INIT_POINTER(net_device_ctx->vf_netdev, NULL);
@@ -2479,6 +2497,7 @@ static int netvsc_probe(struct hv_device *dev,
 
        INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
 
+       init_completion(&net_device_ctx->vf_add);
        spin_lock_init(&net_device_ctx->lock);
        INIT_LIST_HEAD(&net_device_ctx->reconfig_events);
        INIT_DELAYED_WORK(&net_device_ctx->vf_takeover, netvsc_vf_setup);