Hello.
On 5/28/2015 2:25 PM, Jeff Kirsher wrote:
From: John Fastabend <john.r.fastab...@intel.com>
The ring_cookie is 64 bits wide which is much larger than can be used
for actual queue index values. So provide some helper routines to
pack a VF index into the cookie. This is useful to steer packets to
a VF ring without having to know the queue layout of the device.
CC: Alex Duyck <alexander.h.du...@redhat.com>
Signed-off-by: John Fastabend <john.r.fastab...@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirs...@intel.com>
---
include/uapi/linux/ethtool.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index ae832b4..0594933 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -796,6 +796,31 @@ struct ethtool_rx_flow_spec {
__u32 location;
};
+/* How rings are layed out when accessing virtual functions or
s/layed/laid/.
+ * offloaded queues is device specific. To allow users to do flow
+ * steering and specify these queues the ring cookie is partitioned
+ * into a 32bit queue index with an 8 bit virtual function id.
+ * This also leaves the 3bytes for further specifiers. It is possible
+ * future devices may support more than 256 virtual functions if
+ * devices start supporting PCIe w/ARI. However at the moment I
+ * do not know of any devices that support this so I do not reserve
+ * space for this at this time. If a future patch consumes the next
+ * byte it should be aware of this possiblity.
Possibility.
[...]
WBR, Sergei
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