datapath: Fix kernel panic on ovs_flow_free

[sliver-openvswitch.git] / FAQ

diff --git a/FAQ b/FAQ
index 2508c8c..75d9e6b 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -173,22 +173,17 @@ Q: Should userspace or kernel be upgraded first to minimize downtime?
 Q: What features are not available in the Open vSwitch kernel datapath
    that ships as part of the upstream Linux kernel?
 
-A: The kernel module in upstream Linux 3.3 and later does not include
-   tunnel virtual ports, that is, interfaces with type "gre",
-   "ipsec_gre", "gre64", "ipsec_gre64", "vxlan", or "lisp".  It is
-   possible to create tunnels in Linux and attach them to Open vSwitch
-   as system devices.  However, they cannot be dynamically created
-   through the OVSDB protocol or set the tunnel ids as a flow action.
-
-   Work is in progress in adding tunnel virtual ports to the upstream
-   Linux version of the Open vSwitch kernel module.  For now, if you
-   need these features, use the kernel module from the Open vSwitch
+A: The kernel module in upstream Linux does not include support for
+   LISP. Work is in progress to add support for LISP to the upstream
+   Linux version of the Open vSwitch kernel module. For now, if you
+   need this feature, use the kernel module from the Open vSwitch
    distribution instead of the upstream Linux kernel module.
 
-   The upstream kernel module does not include patch ports, but this
-   only matters for Open vSwitch 1.9 and earlier, because Open vSwitch
-   1.10 and later implement patch ports without using this kernel
-   feature.
+   Certain features require kernel support to function or to have
+   reasonable performance. If the ovs-vswitchd log file indicates that
+   a feature is not supported, consider upgrading to a newer upstream
+   Linux release or using the kernel module paired with the userspace
+   distribution.
 
 Q: What features are not available when using the userspace datapath?
 
@@ -646,6 +641,17 @@ A: In version 1.9.0, OVS switched to using a single datapath that is
    shared by all bridges of that type.  The "ovs-appctl dpif/*"
    commands provide similar functionality that is scoped by the bridge.
 
+Q: I created a GRE port using ovs-vsctl so why can't I send traffic or
+   see the port in the datapath?
+
+A: On Linux kernels before 3.11, the OVS GRE module and Linux GRE module
+   cannot be loaded at the same time. It is likely that on your system the
+   Linux GRE module is already loaded and blocking OVS (to confirm, check
+   dmesg for errors regarding GRE registration). To fix this, unload all
+   GRE modules that appear in lsmod as well as the OVS kernel module. You
+   can then reload the OVS module following the directions in INSTALL,
+   which will ensure that dependencies are satisfied.
+
 
 Quality of Service (QoS)
 ------------------------
@@ -1087,7 +1093,7 @@ A: Open vSwitch 1.9 and earlier support only OpenFlow 1.0 (plus
 
        ovs-vsctl set bridge br0 protocols=OpenFlow10,OpenFlow12,OpenFlow13
 
-   Open vSwitch version 1.12 and later will have experimental support
+   Open vSwitch version 2.0 and later will have experimental support
    for OpenFlow 1.1, 1.2, and 1.3.  On these versions of Open vSwitch,
    the following command enables OpenFlow 1.0, 1.1, 1.2, and 1.3 on
    bridge br0: