The virtio_net driver doesn't dynamically change the RX-ring queue
layout and backing pages, but instead reject XDP setup if all the
conditions for XDP is not meet.  Thus, the xdp_rxq_info also remains
fairly static.  This allow us to simply add the reg/unreg to
net_device open/close functions.

Driver hook points for xdp_rxq_info:
 * reg  : virtnet_open
 * unreg: virtnet_close

V3:
 - bugfix, also setup xdp.rxq in receive_mergeable()
 - Tested bpf-sample prog inside guest on a virtio_net device

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

Since commit 39e6c820 ("net: solve a NAPI race") napi has been able
to be rescheduled within napi_complete_done() even in non-busypoll case,
but virtnet_poll() always enabled interrupts before complete, and when
napi was rescheduled within napi_complete_done() it did not disable
interrupts.
This caused more interrupts when event idx is disabled.

According to commit cbdadbbf ("virtio_net: fix race in RX VQ
processing") we cannot place virtqueue_enable_cb_prepare() after
NAPI_STATE_SCHED is cleared, so disable interrupts again if
napi_complete_done() returned false.

Tested with vhost-user of OVS 2.7 on host, which does not have the event
idx feature.

* Before patch:

$ netperf -t UDP_STREAM -H 192.168.150.253 -l 60 -- -m 1472
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.150.253 () port 0 AF_INET
Socket  Message  Elapsed      Messages
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

212992    1472   60.00     32763206      0    6430.32
212992           60.00     23384299           4589.56

Interrupts on guest: 9872369
Packets/interrupt:   2.37

* After patch

$ netperf -t UDP_STREAM -H 192.168.150.253 -l 60 -- -m 1472
MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.150.253 () port 0 AF_INET
Socket  Message  Elapsed      Messages
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

212992    1472   60.00     32794646      0    6436.49
212992           60.00     32793501           6436.27

Interrupts on guest: 4941299
Packets/interrupt:   6.64
Signed-off-by: NToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function virtqueue_get_buf_ctx() could return NULL, the return
value 'buf' need to be checked with NULL, not value 'ctx'.
Signed-off-by: NYunjian Wang <wangyunjian@huawei.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

As the page free path makes no distinction between cache hot and cold
pages, there is no real useful ordering of pages in the free list that
allocation requests can take advantage of.  Juding from the users of
__GFP_COLD, it is likely that a number of them are the result of copying
other sites instead of actually measuring the impact.  Remove the
__GFP_COLD parameter which simplifies a number of paths in the page
allocator.

This is potentially controversial but bear in mind that the size of the
per-cpu pagelists versus modern cache sizes means that the whole per-cpu
list can often fit in the L3 cache.  Hence, there is only a potential
benefit for microbenchmarks that alloc/free pages in a tight loop.  It's
even worse when THP is taken into account which has little or no chance
of getting a cache-hot page as the per-cpu list is bypassed and the
zeroing of multiple pages will thrash the cache anyway.

The truncate microbenchmarks are not shown as this patch affects the
allocation path and not the free path.  A page fault microbenchmark was
tested but it showed no sigificant difference which is not surprising
given that the __GFP_COLD branches are a miniscule percentage of the
fault path.

Link: http://lkml.kernel.org/r/20171018075952.10627-9-mgorman@techsingularity.netSigned-off-by: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ndo_xdp is a control path callback for setting up XDP in the
driver.  We can reuse it for other forms of communication
between the eBPF stack and the drivers.  Rename the callback
and associated structures and definitions.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NSimon Horman <simon.horman@netronome.com>
Reviewed-by: NQuentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This work enables generic transfer of metadata from XDP into skb. The
basic idea is that we can make use of the fact that the resulting skb
must be linear and already comes with a larger headroom for supporting
bpf_xdp_adjust_head(), which mangles xdp->data. Here, we base our work
on a similar principle and introduce a small helper bpf_xdp_adjust_meta()
for adjusting a new pointer called xdp->data_meta. Thus, the packet has
a flexible and programmable room for meta data, followed by the actual
packet data. struct xdp_buff is therefore laid out that we first point
to data_hard_start, then data_meta directly prepended to data followed
by data_end marking the end of packet. bpf_xdp_adjust_head() takes into
account whether we have meta data already prepended and if so, memmove()s
this along with the given offset provided there's enough room.

xdp->data_meta is optional and programs are not required to use it. The
rationale is that when we process the packet in XDP (e.g. as DoS filter),
we can push further meta data along with it for the XDP_PASS case, and
give the guarantee that a clsact ingress BPF program on the same device
can pick this up for further post-processing. Since we work with skb
there, we can also set skb->mark, skb->priority or other skb meta data
out of BPF, thus having this scratch space generic and programmable
allows for more flexibility than defining a direct 1:1 transfer of
potentially new XDP members into skb (it's also more efficient as we
don't need to initialize/handle each of such new members). The facility
also works together with GRO aggregation. The scratch space at the head
of the packet can be multiple of 4 byte up to 32 byte large. Drivers not
yet supporting xdp->data_meta can simply be set up with xdp->data_meta
as xdp->data + 1 as bpf_xdp_adjust_meta() will detect this and bail out,
such that the subsequent match against xdp->data for later access is
guaranteed to fail.

The verifier treats xdp->data_meta/xdp->data the same way as we treat
xdp->data/xdp->data_end pointer comparisons. The requirement for doing
the compare against xdp->data is that it hasn't been modified from it's
original address we got from ctx access. It may have a range marking
already from prior successful xdp->data/xdp->data_end pointer comparisons
though.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We should set xdp_xmit only when xdp_do_redirect() succeed.

Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch tries to add XDP_REDIRECT for virtio-net. The changes are
not complex as we could use exist XDP_TX helpers for most of the
work. The rest is passing the XDP_TX to NAPI handler for implementing
batching.

Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There's no need to add packet len average in the case of XDP_PASS
since it will be done soon after skb is created.

Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

CC: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change is needed to not fool drop monitor.
(perf record ... -e skb:kfree_skb )

Packets were properly sent and are consumed after TX completion.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The show and store functions don't need/use the attribute.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Kernel coding style is to put paren around operand of sizeof.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The array guest_offloads is local to the source and does not need to
be in global scope, so make it static. Also tweak formatting.

Cleans up sparse warnings:
symbol 'guest_offloads' was not declared. Should it be static?
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Seth Forshee noticed a performance degradation with some workloads.
This turns out to be due to packet drops.  Euan Kemp noticed that this
is because we drop all packets where length exceeds the truesize, but
for some packets we add in extra memory without updating the truesize.
This in turn was kept around unchanged from ab7db917 ("virtio-net:
auto-tune mergeable rx buffer size for improved performance").  That
commit had an internal reason not to account for the extra space: not
enough bits to do it.  No longer true so let's account for the allocated
length exactly.

Many thanks to Seth Forshee for the report and bisecting and Euan Kemp
for debugging the issue.

Fixes: 680557cf ("virtio_net: rework mergeable buffer handling")
Reported-by: NEuan Kemp <euan.kemp@coreos.com>
Tested-by: NEuan Kemp <euan.kemp@coreos.com>
Reported-by: NSeth Forshee <seth.forshee@canonical.com>
Tested-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After removing the reset function, the freeze and restore functions
are now unused when CONFIG_PM_SLEEP is disabled:

drivers/net/virtio_net.c:1881:12: error: 'virtnet_restore_up' defined but not used [-Werror=unused-function]
 static int virtnet_restore_up(struct virtio_device *vdev)
drivers/net/virtio_net.c:1859:13: error: 'virtnet_freeze_down' defined but not used [-Werror=unused-function]
 static void virtnet_freeze_down(struct virtio_device *vdev)

A more robust way to do this is to remove the #ifdef around the callers
and instead mark them as __maybe_unused. The compiler will now just
silently drop the unused code.

Fixes: 4941d472 ("virtio-net: do not reset during XDP set")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Unregister the driver before removing multi-instance hotplug
callbacks. This order avoids the warning issued from
__cpuhp_remove_state_cpuslocked when the number of remaining
instances isn't yet zero.

Fixes: 8017c279 ("net/virtio-net: Convert to hotplug state machine")
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Current XDP implementation wants guest offloads feature to be disabled
on device. This is inconvenient and means guest can't benefit from
offloads if XDP is not used. This patch tries to address this
limitation by disabling the offloads on demand through control guest
offloads. Guest offloads will be disabled and enabled on demand on XDP
set.
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently reset the device during XDP set, the main reason is
that we allocate more headroom with XDP (for header adjustment).

This works but causes network downtime for users.

Previous patches encoded the headroom in the buffer context,
this makes it possible to detect the case where a buffer
with headroom insufficient for XDP is added to the queue and
XDP is enabled afterwards.

Upon detection, we handle this case by copying the packet
(slow, but it's a temporary condition).
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use ctx API to store headroom for small buffers.
Following patches will retrieve this info and use it for XDP.
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pack headroom into ctx - this way when we get a buffer we can figure out
the actual headroom that was allocated for the buffer. Will be helpful
to optimize switching between XDP and non-XDP modes which have different
headroom requirements.
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is going away.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: commit d45b897b ("virtio_net: allow specifying context for rx")
Signed-off-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We don't hold any tx lock when trying to disable TX during reset, this
would lead a use after free since ndo_start_xmit() tries to access
the virtqueue which has already been freed. Fix this by using
netif_tx_disable() before freeing the vqs, this could make sure no tx
after vq freeing.
Reported-by: NJean-Philippe Menil <jpmenil@gmail.com>
Tested-by: NJean-Philippe Menil <jpmenil@gmail.com>
Fixes commit f600b690 ("virtio_net: Add XDP support")
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NRobert McCabe <robert.mccabe@rockwellcollins.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support to virtio_net to report bpf_prog ID during XDP_QUERY_PROG.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Acked-by: NAlexei Starovoitov <ast@fb.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

    @@
    identifier p, p2;
    expression len, skb, data;
    type t, t2;
    @@
    (
    -p = skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    |
    -p = (t)skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, len);
    |
    -memcpy(p, data, len);
    )

    @@
    type t, t2;
    identifier p, p2;
    expression skb, data;
    @@
    t *p;
    ...
    (
    -p = skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    |
    -p = (t *)skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, sizeof(*p));
    |
    -memcpy(p, data, sizeof(*p));
    )

    @@
    expression skb, len, data;
    @@
    -memcpy(skb_put(skb, len), data, len);
    +skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)
Reviewed-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit d85b758f ("virtio_net: fix support for small rings")
was supposed to increase the buffer size for small rings but had an
unintentional side effect of decreasing it for large rings. This seems
to break some setups - it's not yet clear why, but increasing buffer
size back to what it was before helps.

Fixes: d85b758f ("virtio_net: fix support for small rings")
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reported-by: N"J. Bruce Fields" <bfields@fieldses.org>
Tested-by: NMikulas Patocka <mpatocka@redhat.com>
Tested-by: N"J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since virtio does not provide it's own ndo_features_check handler,
TSO, and now checksum offload, are disabled for stacked vlans.
Re-enable the support and let the host take care of it.  This
restores/improves Guest-to-Guest performance over Q-in-Q vlans.
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NVladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We are printing a decimal value for truesize so we shouldn't use an "0x"
prefix.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We already do a reset once in remove_vq_common -
there appears to be no point in doing another one
when we add/remove XDP.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

When ring size is small (<32 entries) making buffers smaller means a
full ring might not be able to hold enough buffers to fit a single large
packet.

Make sure a ring full of buffers is large enough to allow at least one
packet of max size.

Fixes: 2613af0e ("virtio_net: migrate mergeable rx buffers to page frag allocators")
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We don't need to align length to any particular
value anymore. Aligning to L1 cache size probably
sill makes sense to reduce false sharing.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Use the new _ctx virtio API to maintain true length for each buffer.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

With mergeable buffers we never use s/g for rx,
so allow specifying context in that case.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Small follow-up to d74a32ac ("xdp: use netlink extended ACK reporting")
in order to let drivers all use the same NL_SET_ERR_MSG_MOD() helper macro
for reporting. This also ensures that we consistently add the driver's
prefix for dumping the report in user space to indicate that the error
message is driver specific and not coming from core code. Furthermore,
NL_SET_ERR_MSG_MOD() now reuses NL_SET_ERR_MSG() and thus makes all macros
check the pointer as suggested.

References: https://www.spinics.net/lists/netdev/msg433267.htmlSigned-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We are going to add more parameters to find_vqs, let's wrap the call so
we don't need to tweak all drivers every time.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Try to carry error messages to the user via the netlink extended
ack message attribute.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid hashing the tx napi struct into napi_hash[], which is used for
busy polling receive queues.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As of tx napi, device down (`ip link set dev $dev down`) hangs unless
tx napi is enabled. Else napi_enable is not called, so napi_disable
will spin on test_and_set_bit NAPI_STATE_SCHED.

Only call napi_disable if tx napi is enabled.

Fixes: 5a719c2552ca ("virtio-net: transmit napi")
Reported-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>