ibmvnic: Client-initiated failover

The IBM vNIC protocol provides support for the user to initiate
a failover from the client LPAR in case the current backing infrastructure
is deemed inadequate or in an error state.

Support for two H_VIOCTL sub-commands for vNIC devices are required
to implement this function. These commands are H_GET_SESSION_TOKEN
and H_SESSION_ERR_DETECTED.

"[H_GET_SESSION_TOKEN] is used to obtain a session token from a VNIC client
adapter.  This token is opaque to the caller and is intended to be used in
tandem with the SESSION_ERROR_DETECTED vioctl subfunction."

"[H_SESSION_ERR_DETECTED] is used to report that the currently active
backing device for a VNIC client adapter is behaving poorly, and that
the hypervisor should attempt to fail over to a different backing device,
if one is available."

To provide tools access to this functionality the vNIC driver creates a
sysfs file that, when written to, will send a request to pHyp to failover
to a different backing device.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index d73755f..57d38b5 100644 (file)
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -295,6 +295,8 @@
 #define H_DISABLE_ALL_VIO_INTS 0x0A
 #define H_DISABLE_VIO_INTERRUPT        0x0B
 #define H_ENABLE_VIO_INTERRUPT 0x0C
+#define H_GET_SESSION_TOKEN    0x19
+#define H_SESSION_ERR_DETECTED 0x1A
 
 
 /* Platform specific hcalls, used by KVM */

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 7d84e20..fd3ef30 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -3656,6 +3656,8 @@ static int ibmvnic_init(struct ibmvnic_adapter *adapter)
        return rc;
 }
 
+static struct device_attribute dev_attr_failover;
+
 static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 {
        struct ibmvnic_adapter *adapter;
@@ -3712,9 +3714,16 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 
        netdev->mtu = adapter->req_mtu - ETH_HLEN;
 
+       rc = device_create_file(&dev->dev, &dev_attr_failover);
+       if (rc) {
+               free_netdev(netdev);
+               return rc;
+       }
+
        rc = register_netdev(netdev);
        if (rc) {
                dev_err(&dev->dev, "failed to register netdev rc=%d\n", rc);
+               device_remove_file(&dev->dev, &dev_attr_failover);
                free_netdev(netdev);
                return rc;
        }
@@ -3740,12 +3749,49 @@ static int ibmvnic_remove(struct vio_dev *dev)
        adapter->state = VNIC_REMOVED;
 
        mutex_unlock(&adapter->reset_lock);
+       device_remove_file(&dev->dev, &dev_attr_failover);
        free_netdev(netdev);
        dev_set_drvdata(&dev->dev, NULL);
 
        return 0;
 }
 
+static ssize_t failover_store(struct device *dev, struct device_attribute *attr,
+                             const char *buf, size_t count)
+{
+       struct net_device *netdev = dev_get_drvdata(dev);
+       struct ibmvnic_adapter *adapter = netdev_priv(netdev);
+       unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+       __be64 session_token;
+       long rc;
+
+       if (!sysfs_streq(buf, "1"))
+               return -EINVAL;
+
+       rc = plpar_hcall(H_VIOCTL, retbuf, adapter->vdev->unit_address,
+                        H_GET_SESSION_TOKEN, 0, 0, 0);
+       if (rc) {
+               netdev_err(netdev, "Couldn't retrieve session token, rc %ld\n",
+                          rc);
+               return -EINVAL;
+       }
+
+       session_token = (__be64)retbuf[0];
+       netdev_dbg(netdev, "Initiating client failover, session id %llx\n",
+                  be64_to_cpu(session_token));
+       rc = plpar_hcall_norets(H_VIOCTL, adapter->vdev->unit_address,
+                               H_SESSION_ERR_DETECTED, session_token, 0, 0);
+       if (rc) {
+               netdev_err(netdev, "Client initiated failover failed, rc %ld\n",
+                          rc);
+               return -EINVAL;
+       }
+
+       return count;
+}
+
+static DEVICE_ATTR(failover, 0200, NULL, failover_store);
+
 static unsigned long ibmvnic_get_desired_dma(struct vio_dev *vdev)
 {
        struct net_device *netdev = dev_get_drvdata(&vdev->dev);