Dequeue zero-copy is no longer supported for vhost-user client mode
in DPDK due to commit [1].
In addition to this, zero-copy mode has been proposed to be marked
deprecated in [2] with removal in the next DPDK LTS release.
This commit deprecates support for vhost-user dequeue zero-copy in OVS
with its removal expected in the next OVS release.
[1] 715070ea10e6 ("vhost: prevent zero-copy with incompatible client
mode")
[2] http://mails.dpdk.org/archives/dev/2020-August/177236.html
Signed-off-by: Ian Stokes <[email protected]>
---
Documentation/topics/dpdk/vhost-user.rst | 5 +++++
NEWS | 2 ++
lib/netdev-dpdk.c | 2 ++
3 files changed, 9 insertions(+)
diff --git a/Documentation/topics/dpdk/vhost-user.rst
b/Documentation/topics/dpdk/vhost-user.rst
index b1eb5d9da..4af738d11 100644
--- a/Documentation/topics/dpdk/vhost-user.rst
+++ b/Documentation/topics/dpdk/vhost-user.rst
@@ -556,6 +556,11 @@ shown with::
vhost-user Dequeue Zero Copy (experimental)
-------------------------------------------
+.. warning::
+
+ vhost-user Dequeue Zero Copy is deprecated in OVS and will be removed in
+ the next release.
+
Normally when dequeuing a packet from a vHost User device, a memcpy operation
must be used to copy that packet from guest address space to host address
space. This memcpy can be removed by enabling dequeue zero-copy like so::
diff --git a/NEWS b/NEWS
index dceda95a3..5d6489f26 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,8 @@ v2.14.0 - xx xxx xxxx
CVE-2020-10726, this DPDK version is strongly recommended to be used.
* New 'ovs-appctl dpdk/log-list' and 'ovs-appctl dpdk/log-set' commands
to list and change log levels in DPDK components.
+ * Vhost-user Dequeue zero-copy support is deprecated and will be removed
+ in the next release.
- Linux datapath:
* Support for kernel versions up to 5.5.x.
- AF_XDP:
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 44ebf96da..27bf3b6ed 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -5079,6 +5079,8 @@ netdev_dpdk_vhost_client_reconfigure(struct netdev
*netdev)
dev->up.name, dev->vhost_id);
if (zc_enabled) {
VLOG_INFO("Zero copy enabled for vHost port %s", dev->up.name);
+ VLOG_WARN("Zero copy support is deprecated and will be "
+ "removed in the next OVS release.");
}
}
--
2.13.6
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