e1000: add initial XDP support
This patch adds initial support for XDP on e1000 driver. Note e1000
driver does not support page recycling in general which could be
added as a further improvement. However XDP_DROP case will recycle.
XDP_TX and XDP_PASS do not support recycling.
e1000 only supports a single tx queue at this time so the queue
is shared between xdp program and Linux stack. It is possible for
an XDP program to starve the stack in this model.
The XDP program will drop packets on XDP_TX errors. This can occur
when the tx descriptors are exhausted. This behavior is the same
for both shared queue models like e1000 and dedicated tx queue
models used in multiqueue devices. However if both the stack and
XDP are transmitting packets it is perhaps more likely to occur in
the shared queue model. Further refinement to the XDP model may be
possible in the future.
I tested this patch running e1000 in a VM using KVM over a tap
device.
CC: William Tu <u9012063@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
2 files changed
