In merge mode, when xdp is enabled, if the headroom of buf is smaller
than virtnet_get_headroom(), xdp_linearize_page() will be called but the
variable of "headroom" is still 0, which leads to wrong logic after
entering page_to_skb().

[   16.600944] BUG: unable to handle page fault for address: ffffecbfff7b43c8[   16.602175] #PF: supervisor read access in kernel mode
[   16.603350] #PF: error_code(0x0000) - not-present page
[   16.604200] PGD 0 P4D 0
[   16.604686] Oops: 0000 [#1] SMP PTI
[   16.605306] CPU: 4 PID: 715 Comm: sh Tainted: G    B             5.12.0+ #312
[   16.606429] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/04
[   16.608217] RIP: 0010:unmap_page_range+0x947/0xde0
[   16.609014] Code: 00 00 08 00 48 83 f8 01 45 19 e4 41 f7 d4 41 83 e4 03 e9 a4 fd ff ff e8 b7 63 ed ff 4c 89 e0 48 c1 e0 065
[   16.611863] RSP: 0018:ffffc90002503c58 EFLAGS: 00010286
[   16.612720] RAX: ffffecbfff7b43c0 RBX: 00007f19f7203000 RCX: ffffffff812ff359
[   16.613853] RDX: ffff888107778000 RSI: 0000000000000000 RDI: 0000000000000005
[   16.614976] RBP: ffffea000425e000 R08: 0000000000000000 R09: 3030303030303030
[   16.616124] R10: ffffffff82ed7d94 R11: 6637303030302052 R12: 7c00000afffded0f
[   16.617276] R13: 0000000000000001 R14: ffff888119ee7010 R15: 00007f19f7202000
[   16.618423] FS:  0000000000000000(0000) GS:ffff88842fd00000(0000) knlGS:0000000000000000
[   16.619738] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   16.620670] CR2: ffffecbfff7b43c8 CR3: 0000000103220005 CR4: 0000000000370ee0
[   16.621792] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   16.622920] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   16.624047] Call Trace:
[   16.624525]  ? release_pages+0x24d/0x730
[   16.625209]  unmap_single_vma+0xa9/0x130
[   16.625885]  unmap_vmas+0x76/0xf0
[   16.626480]  exit_mmap+0xa0/0x210
[   16.627129]  mmput+0x67/0x180
[   16.627673]  do_exit+0x3d1/0xf10
[   16.628259]  ? do_user_addr_fault+0x231/0x840
[   16.629000]  do_group_exit+0x53/0xd0
[   16.629631]  __x64_sys_exit_group+0x1d/0x20
[   16.630354]  do_syscall_64+0x3c/0x80
[   16.630988]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   16.631828] RIP: 0033:0x7f1a043d0191
[   16.632464] Code: Unable to access opcode bytes at RIP 0x7f1a043d0167.
[   16.633502] RSP: 002b:00007ffe3d993308 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[   16.634737] RAX: ffffffffffffffda RBX: 00007f1a044c9490 RCX: 00007f1a043d0191
[   16.635857] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
[   16.636986] RBP: 0000000000000000 R08: ffffffffffffff88 R09: 0000000000000001
[   16.638120] R10: 0000000000000008 R11: 0000000000000246 R12: 00007f1a044c9490
[   16.639245] R13: 0000000000000001 R14: 00007f1a044c9968 R15: 0000000000000000
[   16.640408] Modules linked in:
[   16.640958] CR2: ffffecbfff7b43c8
[   16.641557] ---[ end trace bc4891c6ce46354c ]---
[   16.642335] RIP: 0010:unmap_page_range+0x947/0xde0
[   16.643135] Code: 00 00 08 00 48 83 f8 01 45 19 e4 41 f7 d4 41 83 e4 03 e9 a4 fd ff ff e8 b7 63 ed ff 4c 89 e0 48 c1 e0 065
[   16.645983] RSP: 0018:ffffc90002503c58 EFLAGS: 00010286
[   16.646845] RAX: ffffecbfff7b43c0 RBX: 00007f19f7203000 RCX: ffffffff812ff359
[   16.647970] RDX: ffff888107778000 RSI: 0000000000000000 RDI: 0000000000000005
[   16.649091] RBP: ffffea000425e000 R08: 0000000000000000 R09: 3030303030303030
[   16.650250] R10: ffffffff82ed7d94 R11: 6637303030302052 R12: 7c00000afffded0f
[   16.651394] R13: 0000000000000001 R14: ffff888119ee7010 R15: 00007f19f7202000
[   16.652529] FS:  0000000000000000(0000) GS:ffff88842fd00000(0000) knlGS:0000000000000000
[   16.653887] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   16.654841] CR2: ffffecbfff7b43c8 CR3: 0000000103220005 CR4: 0000000000370ee0
[   16.655992] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   16.657150] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   16.658290] Kernel panic - not syncing: Fatal exception
[   16.659613] Kernel Offset: disabled
[   16.660234] ---[ end Kernel panic - not syncing: Fatal exception ]---

Fixes: fb32856b ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom")
Signed-off-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Not all virtio_net devices support the ctrl queue feature. Thus, there
is no need to allocate unused resources.
Signed-off-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Link: https://lore.kernel.org/r/20210502093319.61313-1-mgurtovoy@nvidia.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>

When "headroom" > 0, the actual allocated memory space is the entire
page, so the address of the page should be used when passing it to
build_skb().

BUG: KASAN: use-after-free in skb_gro_receive (net/core/skbuff.c:4260)
Write of size 16 at addr ffff88811619fffc by task kworker/u9:0/534
CPU: 2 PID: 534 Comm: kworker/u9:0 Not tainted 5.12.0-rc7-custom-16372-gb150be05b806 #3382
Hardware name: QEMU MSN2700, BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Workqueue: xprtiod xs_stream_data_receive_workfn [sunrpc]
Call Trace:
 <IRQ>
dump_stack (lib/dump_stack.c:122)
print_address_description.constprop.0 (mm/kasan/report.c:233)
kasan_report.cold (mm/kasan/report.c:400 mm/kasan/report.c:416)
skb_gro_receive (net/core/skbuff.c:4260)
tcp_gro_receive (net/ipv4/tcp_offload.c:266 (discriminator 1))
tcp4_gro_receive (net/ipv4/tcp_offload.c:316)
inet_gro_receive (net/ipv4/af_inet.c:1545 (discriminator 2))
dev_gro_receive (net/core/dev.c:6075)
napi_gro_receive (net/core/dev.c:6168 net/core/dev.c:6198)
receive_buf (drivers/net/virtio_net.c:1151) virtio_net
virtnet_poll (drivers/net/virtio_net.c:1415 drivers/net/virtio_net.c:1519) virtio_net
__napi_poll (net/core/dev.c:6964)
net_rx_action (net/core/dev.c:7033 net/core/dev.c:7118)
__do_softirq (./arch/x86/include/asm/jump_label.h:25 ./include/linux/jump_label.h:200 ./include/trace/events/irq.h:142 kernel/softirq.c:346)
irq_exit_rcu (kernel/softirq.c:221 kernel/softirq.c:422 kernel/softirq.c:434)
common_interrupt (arch/x86/kernel/irq.c:240 (discriminator 14))
</IRQ>

Fixes: fb32856b ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom")
Signed-off-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Reported-by: NIdo Schimmel <idosch@nvidia.com>
Tested-by: NIdo Schimmel <idosch@nvidia.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

KASAN/syzbot had 4 reports, one of them being:

BUG: KASAN: slab-out-of-bounds in memcpy include/linux/fortify-string.h:191 [inline]
BUG: KASAN: slab-out-of-bounds in page_to_skb+0x5cf/0xb70 drivers/net/virtio_net.c:480
Read of size 12 at addr ffff888014a5f800 by task systemd-udevd/8445

CPU: 0 PID: 8445 Comm: systemd-udevd Not tainted 5.12.0-rc8-next-20210419-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:436
 check_region_inline mm/kasan/generic.c:180 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:186
 memcpy+0x20/0x60 mm/kasan/shadow.c:65
 memcpy include/linux/fortify-string.h:191 [inline]
 page_to_skb+0x5cf/0xb70 drivers/net/virtio_net.c:480
 receive_mergeable drivers/net/virtio_net.c:1009 [inline]
 receive_buf+0x2bc0/0x6250 drivers/net/virtio_net.c:1119
 virtnet_receive drivers/net/virtio_net.c:1411 [inline]
 virtnet_poll+0x568/0x10b0 drivers/net/virtio_net.c:1516
 __napi_poll+0xaf/0x440 net/core/dev.c:6962
 napi_poll net/core/dev.c:7029 [inline]
 net_rx_action+0x801/0xb40 net/core/dev.c:7116
 __do_softirq+0x29b/0x9fe kernel/softirq.c:559
 invoke_softirq kernel/softirq.c:433 [inline]
 __irq_exit_rcu+0x136/0x200 kernel/softirq.c:637
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
 common_interrupt+0xa4/0xd0 arch/x86/kernel/irq.c:240

Fixes: fb32856b ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Reported-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

build_skb() is supposed to be followed by
skb_reserve(skb, NET_IP_ALIGN), so that IP headers are word-aligned.
(Best practice is to reserve NET_IP_ALIGN+NET_SKB_PAD, but the NET_SKB_PAD
part is only a performance optimization if tunnel encaps are added.)

Unfortunately virtio_net has not provisioned this reserve.
We can only use build_skb() for arches where NET_IP_ALIGN == 0

We might refine this later, with enough testing.

Fixes: fb32856b ("virtio-net: page_to_skb() use build_skb when there's sufficient tailroom")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In page_to_skb(), if we have enough tailroom to save skb_shared_info, we
can use build_skb to create skb directly. No need to alloc for
additional space. And it can save a 'frags slot', which is very friendly
to GRO.

Here, if the payload of the received package is too small (less than
GOOD_COPY_LEN), we still choose to copy it directly to the space got by
napi_alloc_skb. So we can reuse these pages.

Testing Machine:
    The four queues of the network card are bound to the cpu1.

Test command:
    for ((i=0;i<5;++i)); do sockperf tp --ip 192.168.122.64 -m 1000 -t 150& done

The size of the udp package is 1000, so in the case of this patch, there
will always be enough tailroom to use build_skb. The sent udp packet
will be discarded because there is no port to receive it. The irqsoftd
of the machine is 100%, we observe the received quantity displayed by
sar -n DEV 1:

no build_skb:  956864.00 rxpck/s
build_skb:    1158465.00 rxpck/s
Signed-off-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Suggested-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Xuan Zhuo reported that commit 3226b158 ("net: avoid 32 x truesize
under-estimation for tiny skbs") brought  a ~10% performance drop.

The reason for the performance drop was that GRO was forced
to chain sk_buff (using skb_shinfo(skb)->frag_list), which
uses more memory but also cause packet consumers to go over
a lot of overhead handling all the tiny skbs.

It turns out that virtio_net page_to_skb() has a wrong strategy :
It allocates skbs with GOOD_COPY_LEN (128) bytes in skb->head, then
copies 128 bytes from the page, before feeding the packet to GRO stack.

This was suboptimal before commit 3226b158 ("net: avoid 32 x truesize
under-estimation for tiny skbs") because GRO was using 2 frags per MSS,
meaning we were not packing MSS with 100% efficiency.

Fix is to pull only the ethernet header in page_to_skb()

Then, we change virtio_net_hdr_to_skb() to pull the missing
headers, instead of assuming they were already pulled by callers.

This fixes the performance regression, but could also allow virtio_net
to accept packets with more than 128bytes of headers.

Many thanks to Xuan Zhuo for his report, and his tests/help.

Fixes: 3226b158 ("net: avoid 32 x truesize under-estimation for tiny skbs")
Reported-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Link: https://www.spinics.net/lists/netdev/msg731397.htmlCo-Developed-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the xps maps (xps_cpus_map and xps_rxqs_map) to an array in
net_device. That will simplify a lot the code removing the need for lots
of if/else conditionals as the correct map will be available using its
offset in the array.

This should not modify the xps maps behaviour in any way.
Suggested-by: NAlexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: NAntoine Tenart <atenart@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We want to change the current ndo_xdp_xmit drop semantics because it will
allow us to implement better queue overflow handling. This is working
towards the larger goal of a XDP TX queue-hook. Move XDP_REDIRECT error
path handling from each XDP ethernet driver to devmap code. According to
the new APIs, the driver running the ndo_xdp_xmit pointer, will break tx
loop whenever the hw reports a tx error and it will just return to devmap
caller the number of successfully transmitted frames. It will be devmap
responsibility to free dropped frames.

Move each XDP ndo_xdp_xmit capable driver to the new APIs:

- veth
- virtio-net
- mvneta
- mvpp2
- socionext
- amazon ena
- bnxt
- freescale (dpaa2, dpaa)
- xen-frontend
- qede
- ice
- igb
- ixgbe
- i40e
- mlx5
- ti (cpsw, cpsw-new)
- tun
- sfc
Signed-off-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: NCamelia Groza <camelia.groza@nxp.com>
Acked-by: NEdward Cree <ecree.xilinx@gmail.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NShay Agroskin <shayagr@amazon.com>
Link: https://lore.kernel.org/bpf/ed670de24f951cfd77590decf0229a0ad7fd12f6.1615201152.git.lorenzo@kernel.org

Update the code to replace instances of snprintf and a pointer update with
just calling ethtool_sprintf.

Also replace the char pointer with a u8 pointer to avoid having to recast
the pointer type.
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The number of queues implemented by many virtio backends is limited,
especially some machines have a large number of CPUs. In this case, it
is often impossible to allocate a separate queue for
XDP_TX/XDP_REDIRECT, then xdp cannot be loaded to work, even xdp does
not use the XDP_TX/XDP_REDIRECT.

This patch allows XDP_TX/XDP_REDIRECT to run by reuse the existing SQ
with __netif_tx_lock() hold when there are not enough queues.
Signed-off-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: NDust Li <dust.li@linux.alibaba.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Virtio net supports the case where the skb linear space is empty, so
add priv_flags.
Signed-off-by: NXuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210218204908.5455-4-alobakin@pm.me

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a goto statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115Signed-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/cb9b9534572bc476f4fb7b49a73dc8646b780c84.1605896060.git.gustavoars@kernel.orgSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>

Introduce xdp_prepare_buff utility routine to initialize per-descriptor
xdp_buff fields (e.g. xdp_buff pointers). Rely on xdp_prepare_buff() in
all XDP capable drivers.
Signed-off-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Acked-by: NShay Agroskin <shayagr@amazon.com>
Acked-by: NMartin Habets <habetsm.xilinx@gmail.com>
Acked-by: NCamelia Groza <camelia.groza@nxp.com>
Acked-by: NMarcin Wojtas <mw@semihalf.com>
Link: https://lore.kernel.org/bpf/45f46f12295972a97da8ca01990b3e71501e9d89.1608670965.git.lorenzo@kernel.orgSigned-off-by: NAlexei Starovoitov <ast@kernel.org>

Introduce xdp_init_buff utility routine to initialize xdp_buff fields
const over NAPI iterations (e.g. frame_sz or rxq pointer). Rely on
xdp_init_buff in all XDP capable drivers.
Signed-off-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Acked-by: NShay Agroskin <shayagr@amazon.com>
Acked-by: NMartin Habets <habetsm.xilinx@gmail.com>
Acked-by: NCamelia Groza <camelia.groza@nxp.com>
Acked-by: NMarcin Wojtas <mw@semihalf.com>
Link: https://lore.kernel.org/bpf/7f8329b6da1434dc2b05a77f2e800b29628a8913.1608670965.git.lorenzo@kernel.orgSigned-off-by: NAlexei Starovoitov <ast@kernel.org>

virtnet_set_channels can recursively call cpus_read_lock if CONFIG_XPS
and CONFIG_HOTPLUG are enabled.

The path is:
    virtnet_set_channels - calls get_online_cpus(), which is a trivial
wrapper around cpus_read_lock()
    netif_set_real_num_tx_queues
    netif_reset_xps_queues_gt
    netif_reset_xps_queues - calls cpus_read_lock()

This call chain and potential deadlock happens when the number of TX
queues is reduced.

This commit the removes netif_set_real_num_[tr]x_queues calls from
inside the get/put_online_cpus section, as they don't require that it
be held.

Fixes: 47be2479 ("virtio-net: fix the set affinity bug when CPU IDs are not consecutive")
Signed-off-by: NJeff Dike <jdike@akamai.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20201223025421.671-1-jdike@akamai.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Set a negative error code intead of returning success if the MTU has
been changed to something invalid.

Fixes: fe36cbe0 ("virtio_net: clear MTU when out of range")
Reported-by: NRobert Buhren <robert.buhren@sect.tu-berlin.de>
Reported-by: NFelicitas Hetzelt <file@sect.tu-berlin.de>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/X8pGVJSeeCdII1Ys@mwandaSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>

Add napi_id to the xdp_rxq_info structure, and make sure the XDP
socket pick up the napi_id in the Rx path. The napi_id is used to find
the corresponding NAPI structure for socket busy polling.
Signed-off-by: NBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NTariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/bpf/20201130185205.196029-7-bjorn.topel@gmail.com

This reverts commit 3618ad2a.

When control vq is not negotiated, that commit causes a crash:

[   72.229171] kernel BUG at drivers/net/virtio_net.c:1667!
[   72.230266] invalid opcode: 0000 [#1] PREEMPT SMP
[   72.231172] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc8-02934-g3618ad2a #1
[   72.231172] EIP: virtnet_send_command+0x120/0x140
[   72.231172] Code: 00 0f 94 c0 8b 7d f0 65 33 3d 14 00 00 00 75 1c 8d 65 f4 5b 5e 5f 5d c3 66 90 be 01 00 00 00 e9 6e ff ff ff 8d b6 00
+00 00 00 <0f> 0b e8 d9 bb 82 00 eb 17 8d b4 26 00 00 00 00 8d b4 26 00 00 00
[   72.231172] EAX: 0000000d EBX: f72895c0 ECX: 00000017 EDX: 00000011
[   72.231172] ESI: f7197800 EDI: ed69bd00 EBP: ed69bcf4 ESP: ed69bc98
[   72.231172] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246
[   72.231172] CR0: 80050033 CR2: 00000000 CR3: 02c84000 CR4: 000406f0
[   72.231172] Call Trace:
[   72.231172]  ? __virt_addr_valid+0x45/0x60
[   72.231172]  ? ___cache_free+0x51f/0x760
[   72.231172]  ? kobject_uevent_env+0xf4/0x560
[   72.231172]  virtnet_set_guest_offloads+0x4d/0x80
[   72.231172]  virtnet_set_features+0x85/0x120
[   72.231172]  ? virtnet_set_guest_offloads+0x80/0x80
[   72.231172]  __netdev_update_features+0x27a/0x8e0
[   72.231172]  ? kobject_uevent+0xa/0x20
[   72.231172]  ? netdev_register_kobject+0x12c/0x160
[   72.231172]  register_netdevice+0x4fe/0x740
[   72.231172]  register_netdev+0x1c/0x40
[   72.231172]  virtnet_probe+0x728/0xb60
[   72.231172]  ? _raw_spin_unlock+0x1d/0x40
[   72.231172]  ? virtio_vdpa_get_status+0x1c/0x20
[   72.231172]  virtio_dev_probe+0x1c6/0x271
[   72.231172]  really_probe+0x195/0x2e0
[   72.231172]  driver_probe_device+0x26/0x60
[   72.231172]  device_driver_attach+0x49/0x60
[   72.231172]  __driver_attach+0x46/0xc0
[   72.231172]  ? device_driver_attach+0x60/0x60
[   72.231172]  bus_add_driver+0x197/0x1c0
[   72.231172]  driver_register+0x66/0xc0
[   72.231172]  register_virtio_driver+0x1b/0x40
[   72.231172]  virtio_net_driver_init+0x61/0x86
[   72.231172]  ? veth_init+0x14/0x14
[   72.231172]  do_one_initcall+0x76/0x2e4
[   72.231172]  ? rdinit_setup+0x2a/0x2a
[   72.231172]  do_initcalls+0xb2/0xd5
[   72.231172]  kernel_init_freeable+0x14f/0x179
[   72.231172]  ? rest_init+0x100/0x100
[   72.231172]  kernel_init+0xd/0xe0
[   72.231172]  ret_from_fork+0x1c/0x30
[   72.231172] Modules linked in:
[   72.269563] ---[ end trace a6ebc4afea0e6cb1 ]---

The reason is that virtnet_set_features now calls virtnet_set_guest_offloads
unconditionally, it used to only call it when there is something
to configure.

If device does not have a control vq, everything breaks.

Revert the original commit for now.

Cc: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Fixes: 3618ad2a ("virtio-net: ethtool configurable RXCSUM")
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20201021142944.13615-1-mst@redhat.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Allow user configuring RXCSUM separately with ethtool -K,
reusing the existing virtnet_set_guest_offloads helper
that configures RXCSUM for XDP. This is conditional on
VIRTIO_NET_F_CTRL_GUEST_OFFLOADS.

If Rx checksum is disabled, LRO should also be disabled.
Signed-off-by: NTonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20201012015820.62042-1-xiangxia.m.yue@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Open vSwitch and Linux bridge will disable LRO of the interface
when this interface added to them. Now when disable the LRO, the
virtio-net csum is disable too. That drops the forwarding performance.

Fixes: a02e8964 ("virtio-net: ethtool configurable LRO")
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: NTonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We allow drivers to call napi_hash_del() before calling
netif_napi_del() to batch RCU grace periods. This makes
the API asymmetric and leaks internal implementation details.
Soon we will want the grace period to protect more than just
the NAPI hash table.

Restructure the API and have drivers call a new function -
__netif_napi_del() if they want to take care of RCU waits.

Note that only core was checking the return status from
napi_hash_del() so the new helper does not report if the
NAPI was actually deleted.

Some notes on driver oddness:
 - veth observed the grace period before calling netif_napi_del()
   but that should not matter
 - myri10ge observed normal RCU flavor
 - bnx2x and enic did not actually observe the grace period
   (unless they did so implicitly)
 - virtio_net and enic only unhashed Rx NAPIs

The last two points seem to indicate that the calls to
napi_hash_del() were a left over rather than an optimization.
Regardless, it's easy enough to correct them.

This patch may introduce extra synchronize_net() calls for
interfaces which set NAPI_STATE_NO_BUSY_POLL and depend on
free_netdev() to call netif_napi_del(). This seems inevitable
since we want to use RCU for netpoll dev->napi_list traversal,
and almost no drivers set IFF_DISABLE_NETPOLL.
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

Speed and duplex config fields depend on VIRTIO_NET_F_SPEED_DUPLEX
which being 63>31 depends on VIRTIO_F_VERSION_1.

Accordingly, use LE accessors for these fields.
Reported-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Now that BPF program/link management is centralized in generic net_device
code, kernel code never queries program id from drivers, so
XDP_QUERY_PROG/XDP_QUERY_PROG_HW commands are unnecessary.

This patch removes all the implementations of those commands in kernel, along
the xdp_attachment_query().

This patch was compile-tested on allyesconfig.
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200722064603.3350758-10-andriin@fb.com

In order to use standard 'xdp' prefix, rename convert_to_xdp_frame
utility routine in xdp_convert_buff_to_frame and replace all the
occurrences
Signed-off-by: NLorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/6344f739be0d1a08ab2b9607584c4d5478c8c083.1590698295.git.lorenzo@kernel.org

The virtio_net driver is running inside the guest-OS. There are two
XDP receive code-paths in virtio_net, namely receive_small() and
receive_mergeable(). The receive_big() function does not support XDP.

In receive_small() the frame size is available in buflen. The buffer
backing these frames are allocated in add_recvbuf_small() with same
size, except for the headroom, but tailroom have reserved room for
skb_shared_info. The headroom is encoded in ctx pointer as a value.

In receive_mergeable() the frame size is more dynamic. There are two
basic cases: (1) buffer size is based on a exponentially weighted
moving average (see DECLARE_EWMA) of packet length. Or (2) in case
virtnet_get_headroom() have any headroom then buffer size is
PAGE_SIZE. The ctx pointer is this time used for encoding two values;
the buffer len "truesize" and headroom. In case (1) if the rx buffer
size is underestimated, the packet will have been split over more
buffers (num_buf info in virtio_net_hdr_mrg_rxbuf placed in top of
buffer area). If that happens the XDP path does a xdp_linearize_page
operation.

V3: Adjust frame_sz in receive_mergeable() case, spotted by Jason Wang.

The code is really hard to follow, so some hints to reviewers.
The receive_mergeable() case gets frames that were allocated in
add_recvbuf_mergeable() which uses headroom=virtnet_get_headroom(),
and 'buf' ptr is advanced this headroom.  The headroom can only
be 0 or VIRTIO_XDP_HEADROOM, as virtnet_get_headroom is really
simple:

  static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
  {
	return vi->xdp_queue_pairs ? VIRTIO_XDP_HEADROOM : 0;
  }

As frame_sz is an offset size from xdp.data_hard_start, reviewers
should notice how this is calculated in receive_mergeable():

  int offset = buf - page_address(page);
  [...]
  data = page_address(xdp_page) + offset;
  xdp.data_hard_start = data - VIRTIO_XDP_HEADROOM + vi->hdr_len;

The calculated offset will always be VIRTIO_XDP_HEADROOM when
reaching this code.  Thus, xdp.data_hard_start will be page-start
address plus vi->hdr_len.  Given this xdp.frame_sz need to be
reduced with vi->hdr_len size.

IMHO a followup patch should cleanup this code to make it easier
to maintain and understand, but it is outside the scope of this
patchset.
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/bpf/158945344436.97035.9445115070189151680.stgit@firesoul

When we fill up a receive VQ, try_fill_recv currently tries to count
kicks using a 64 bit stats counter. Turns out, on a 32 bit kernel that
uses a seqcount. sequence counts are "lock" constructs where you need to
make sure that writers are serialized.

In turn, this means that we mustn't run two try_fill_recv concurrently.
Which of course we don't. We do run try_fill_recv sometimes from a
softirq napi context, and sometimes from a fully preemptible context,
but the later always runs with napi disabled.

However, when it comes to the seqcount, lockdep is trying to enforce the
rule that the same lock isn't accessed from preemptible and softirq
context - it doesn't know about napi being enabled/disabled. This causes
a false-positive warning:

WARNING: inconsistent lock state
...
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.

As a work around, shut down the warning by switching
to u64_stats_update_begin_irqsave - that works by disabling
interrupts on 32 bit only, is a NOP on 64 bit.
Reported-by: NThomas Gleixner <tglx@linutronix.de>
Suggested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Set ethtool_ops->supported_coalesce_params to let
the core reject unsupported coalescing parameters.

This driver correctly rejects all unsupported parameters.
As a side effect of these changes the error code for
unsupported params changes from EINVAL to EOPNOTSUPP.

v2: correctly handle rx-frames (and adjust the commit msg)
v3: adjust commit message for new error code and member name
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With the ethtool_virtdev_set_link_ksettings function in core/ethtool.c,
ibmveth, netvsc, and virtio now use the core's helper function.

Funtionality changes that pertain to ibmveth driver include:

  1. Changed the initial hardcoded link speed to 1GB.

  2. Added support for allowing a user to change the reported link
  speed via ethtool.

Functionality changes to the netvsc driver include:

  1. When netvsc_get_link_ksettings is called, it will defer to the VF
  device if it exists to pull accelerated networking values, otherwise
  pull default or user-defined values.

  2. Similarly, if netvsc_set_link_ksettings called and a VF device
  exists, the real values of speed and duplex are changed.
Signed-off-by: NCris Forno <cforno12@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement support for transferring XDP meta data into skb for
virtio_net driver; before calling into the program, xdp.data_meta points
to xdp.data, where on program return with pass verdict, we call
into skb_metadata_set().

Tested with the script at
https://github.com/higebu/virtio_net-xdp-metadata-test.
Signed-off-by: NYuya Kusakabe <yuya.kusakabe@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/bpf/20200225033212.437563-2-yuya.kusakabe@gmail.com

We do not want to care about the vnet header in receive_small() if XDP
is loaded, since we can not know whether or not the packet is modified
by XDP.

Fixes: f6b10209 ("virtio-net: switch to use build_skb() for small buffer")
Signed-off-by: NYuya Kusakabe <yuya.kusakabe@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/bpf/20200225033212.437563-1-yuya.kusakabe@gmail.com

virtio_net currently relies on rcu critical section to access the xdp
program in its xdp_xmit handler. However, the pointer to the xdp program
is only used to do a NULL pointer comparison to determine if xdp is
enabled or not.

Use rcu_access_pointer() instead of rcu_dereference() to reflect this.
Then later when we drop rcu_read critical section virtio_net will not
need in special handling.
Signed-off-by: NJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/1580084042-11598-3-git-send-email-john.fastabend@gmail.com

Since the bulk queue used by XDP_REDIRECT now lives in struct net_device,
we can re-use the bulking for the non-map version of the bpf_redirect()
helper. This is a simple matter of having xdp_do_redirect_slow() queue the
frame on the bulk queue instead of sending it out with __bpf_tx_xdp().

Unfortunately we can't make the bpf_redirect() helper return an error if
the ifindex doesn't exit (as bpf_redirect_map() does), because we don't
have a reference to the network namespace of the ingress device at the time
the helper is called. So we have to leave it as-is and keep the device
lookup in xdp_do_redirect_slow().

Since this leaves less reason to have the non-map redirect code in a
separate function, so we get rid of the xdp_do_redirect_slow() function
entirely. This does lose us the tracepoint disambiguation, but fortunately
the xdp_redirect and xdp_redirect_map tracepoints use the same tracepoint
entry structures. This means both can contain a map index, so we can just
amend the tracepoint definitions so we always emit the xdp_redirect(_err)
tracepoints, but with the map ID only populated if a map is present. This
means we retire the xdp_redirect_map(_err) tracepoints entirely, but keep
the definitions around in case someone is still listening for them.

With this change, the performance of the xdp_redirect sample program goes
from 5Mpps to 8.4Mpps (a 68% increase).

Since the flush functions are no longer map-specific, rename the flush()
functions to drop _map from their names. One of the renamed functions is
the xdp_do_flush_map() callback used in all the xdp-enabled drivers. To
keep from having to update all drivers, use a #define to keep the old name
working, and only update the virtual drivers in this patch.
Signed-off-by: NToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/157918768505.1458396.17518057312953572912.stgit@toke.dk

Similarly to bpf_map's refcnt/usercnt, convert bpf_prog's refcnt to atomic64
and remove artificial 32k limit. This allows to make bpf_prog's refcounting
non-failing, simplifying logic of users of bpf_prog_add/bpf_prog_inc.

Validated compilation by running allyesconfig kernel build.
Suggested-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191117172806.2195367-3-andriin@fb.com

commit 174e2381
("sk_buff: drop all skb extensions on free and skb scrubbing") made napi
recycle always drop skb extensions.  The additional skb_ext_del() that is
performed via nf_reset on napi skb recycle is not needed anymore.

Most nf_reset() calls in the stack are there so queued skb won't block
'rmmod nf_conntrack' indefinitely.

This removes the skb_ext_del from nf_reset, and renames it to a more
fitting nf_reset_ct().

In a few selected places, add a call to skb_ext_reset to make sure that
no active extensions remain.

I am submitting this for "net", because we're still early in the release
cycle.  The patch applies to net-next too, but I think the rename causes
needless divergence between those trees.
Suggested-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This change lowers ring buffer reclaim threshold from 1/2*queue to budget
for better performance. According to our test with qemu + dpdk, packet
dropping happens when the guest is not able to provide free buffer in
avail ring timely with default 1/2*queue. The value in the patch has been
tested and does show better performance.

Test setup: iperf3 to generate packets to guest (total 30mins, pps 400k, UDP)
avg packets drop before: 2842
avg packets drop after: 360(-87.3%)

Further, current code suffers from a starvation problem: the amount of
work done by try_fill_recv is not bounded by the budget parameter, thus
(with large queues) once in a while userspace gets blocked for a long
time while queue is being refilled. Trigger refills earlier to make sure
the amount of work to do is limited.
Signed-off-by: Njiangkidd <jiangkidd@hotmail.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

NAPI tx mode improves TCP behavior by enabling TCP small queues (TSQ).
TSQ reduces queuing ("bufferbloat") and burstiness.

Previous measurements have shown significant improvement for
TCP_STREAM style workloads. Such as those in commit 86a5df14
("Merge branch 'virtio-net-tx-napi'").

There has been uncertainty about smaller possible regressions in
latency due to increased reliance on tx interrupts.

The above results did not show that, nor did I observe this when
rerunning TCP_RR on Linux 5.1 this week on a pair of guests in the
same rack. This may be subject to other settings, notably interrupt
coalescing.

In the unlikely case of regression, we have landed a credible runtime
solution. Ethtool can configure it with -C tx-frames [0|1] as of
commit 0c465be1 ("virtio_net: ethtool tx napi configuration").

NAPI tx mode has been the default in Google Container-Optimized OS
(COS) for over half a year, as of release M70 in October 2018,
without any negative reports.

Link: https://marc.info/?l=linux-netdev&m=149305618416472
Link: https://lwn.net/Articles/507065/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>

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not see http www gnu org licenses

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details [based]
  [from] [clk] [highbank] [c] you should have received a copy of the
  gnu general public license along with this program if not see http
  www gnu org licenses

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 355 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NJilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: NSteve Winslow <swinslow@gmail.com>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NYuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>