When a netfront device is set up it registers a netdev fairly early on,
before it has set up the queues and is actually usable. A userspace tool
like NetworkManager will immediately try to open it and access its state
as soon as it appears. The bug can be reproduced by hotplugging VIFs
until the VM runs out of grant refs. It registers the netdev but fails
to set up any queues (since there are no more grant refs). In the
meantime, NetworkManager opens the device and the kernel crashes trying
to access the queues (of which there are none).
Fix this in two ways:
* For initial setup, register the netdev much later, after the queues
are setup. This avoids the race entirely.
* During a suspend/resume cycle, the frontend reconnects to the backend
and the queues are recreated. It is possible (though highly unlikely) to
race with something opening the device and accessing the queues after
they have been destroyed but before they have been recreated. Extend the
region covered by the rtnl semaphore to protect against this race. There
is a possibility that we fail to recreate the queues so check for this
in the open function.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When loading the module after unloading it, the network interface would
not be enabled and thus wouldn't have a backend counterpart and unable
to be used by the guest.
The guest would face errors like:
[root@guest ~]# ethtool -i eth0
Cannot get driver information: No such device
[root@guest ~]# ifconfig eth0
eth0: error fetching interface information: Device not found
This patch initializes the state of the netfront device whenever it is
loaded manually, this state would communicate the netback to create its
device and establish the connection between them.
Signed-off-by: Eduardo Otubo <otubo@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) The forcedeth conversion from pci_*() DMA interfaces to dma_*() ones
missed one spot. From Zhu Yanjun.
2) Missing CRYPTO_SHA256 Kconfig dep in cfg80211, from Johannes Berg.
3) Fix checksum offloading in thunderx driver, from Sunil Goutham.
4) Add SPDX to vm_sockets_diag.h, from Stephen Hemminger.
5) Fix use after free of packet headers in TIPC, from Jon Maloy.
6) "sizeof(ptr)" vs "sizeof(*ptr)" bug in i40e, from Gustavo A R Silva.
7) Tunneling fixes in mlxsw driver, from Petr Machata.
8) Fix crash in fanout_demux_rollover() of AF_PACKET, from Mike
Maloney.
9) Fix race in AF_PACKET bind() vs. NETDEV_UP notifier, from Eric
Dumazet.
10) Fix regression in sch_sfq.c due to one of the timer_setup()
conversions. From Paolo Abeni.
11) SCTP does list_for_each_entry() using wrong struct member, fix from
Xin Long.
12) Don't use big endian netlink attribute read for
IFLA_BOND_AD_ACTOR_SYSTEM, it is in cpu endianness. Also from Xin
Long.
13) Fix mis-initialization of q->link.clock in CBQ scheduler, preventing
adding filters there. From Jiri Pirko.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (67 commits)
ethernet: dwmac-stm32: Fix copyright
net: via: via-rhine: use %p to format void * address instead of %x
net: ethernet: xilinx: Mark XILINX_LL_TEMAC broken on 64-bit
myri10ge: Update MAINTAINERS
net: sched: cbq: create block for q->link.block
atm: suni: remove extraneous space to fix indentation
atm: lanai: use %p to format kernel addresses instead of %x
VSOCK: Don't set sk_state to TCP_CLOSE before testing it
atm: fore200e: use %pK to format kernel addresses instead of %x
ambassador: fix incorrect indentation of assignment statement
vxlan: use __be32 type for the param vni in __vxlan_fdb_delete
bonding: use nla_get_u64 to extract the value for IFLA_BOND_AD_ACTOR_SYSTEM
sctp: use right member as the param of list_for_each_entry
sch_sfq: fix null pointer dereference at timer expiration
cls_bpf: don't decrement net's refcount when offload fails
net/packet: fix a race in packet_bind() and packet_notifier()
packet: fix crash in fanout_demux_rollover()
sctp: remove extern from stream sched
sctp: force the params with right types for sctp csum apis
sctp: force SCTP_ERROR_INV_STRM with __u32 when calling sctp_chunk_fail
...
v2:
* Replace busy wait with wait_event()/wake_up_all()
* Cannot garantee that at the time xennet_remove is called, the
xen_netback state will not be XenbusStateClosed, so added a
condition for that
* There's a small chance for the xen_netback state is
XenbusStateUnknown by the time the xen_netfront switches to Closed,
so added a condition for that.
When unloading module xen_netfront from guest, dmesg would output
warning messages like below:
[ 105.236836] xen:grant_table: WARNING: g.e. 0x903 still in use!
[ 105.236839] deferring g.e. 0x903 (pfn 0x35805)
This problem relies on netfront and netback being out of sync. By the time
netfront revokes the g.e.'s netback didn't have enough time to free all of
them, hence displaying the warnings on dmesg.
The trick here is to make netfront to wait until netback frees all the g.e.'s
and only then continue to cleanup for the module removal, and this is done by
manipulating both device states.
Signed-off-by: Eduardo Otubo <otubo@redhat.com>
Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
RFC791 specifies the minimum MTU to be 68, while xen-net{front|back}
drivers use a minimum value of 0.
When set MTU to 0~67 with xen_net{front|back} driver, the network
will become unreachable immediately, the guest can no longer be pinged.
xen_net{front|back} should not allow the user to set this value which causes
network problems.
Reported-by: Chen Shi <cheshi@redhat.com>
Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
xennet_start_xmit() might copy skb with inappropriate layout
into a fresh one.
Old skb is freed, and at this point it is not a drop, but
a consume. New skb will then be either consumed or dropped.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unavoidable crashes in netfront_resume() and netback_changed() after a
previous fail in talk_to_netback() (e.g. when we fail to read MAC from
xenstore) were discovered. The failure path in talk_to_netback() does
unregister/free for netdev but we don't reset drvdata and we try accessing
it after resume.
Fix the bug by removing the whole xen device completely with
device_unregister(), this guarantees we won't have any calls into netfront
after a failure.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking updates from David Miller:
"Highlights:
1) Support TX_RING in AF_PACKET TPACKET_V3 mode, from Sowmini
Varadhan.
2) Simplify classifier state on sk_buff in order to shrink it a bit.
From Willem de Bruijn.
3) Introduce SIPHASH and it's usage for secure sequence numbers and
syncookies. From Jason A. Donenfeld.
4) Reduce CPU usage for ICMP replies we are going to limit or
suppress, from Jesper Dangaard Brouer.
5) Introduce Shared Memory Communications socket layer, from Ursula
Braun.
6) Add RACK loss detection and allow it to actually trigger fast
recovery instead of just assisting after other algorithms have
triggered it. From Yuchung Cheng.
7) Add xmit_more and BQL support to mvneta driver, from Simon Guinot.
8) skb_cow_data avoidance in esp4 and esp6, from Steffen Klassert.
9) Export MPLS packet stats via netlink, from Robert Shearman.
10) Significantly improve inet port bind conflict handling, especially
when an application is restarted and changes it's setting of
reuseport. From Josef Bacik.
11) Implement TX batching in vhost_net, from Jason Wang.
12) Extend the dummy device so that VF (virtual function) features,
such as configuration, can be more easily tested. From Phil
Sutter.
13) Avoid two atomic ops per page on x86 in bnx2x driver, from Eric
Dumazet.
14) Add new bpf MAP, implementing a longest prefix match trie. From
Daniel Mack.
15) Packet sample offloading support in mlxsw driver, from Yotam Gigi.
16) Add new aquantia driver, from David VomLehn.
17) Add bpf tracepoints, from Daniel Borkmann.
18) Add support for port mirroring to b53 and bcm_sf2 drivers, from
Florian Fainelli.
19) Remove custom busy polling in many drivers, it is done in the core
networking since 4.5 times. From Eric Dumazet.
20) Support XDP adjust_head in virtio_net, from John Fastabend.
21) Fix several major holes in neighbour entry confirmation, from
Julian Anastasov.
22) Add XDP support to bnxt_en driver, from Michael Chan.
23) VXLAN offloads for enic driver, from Govindarajulu Varadarajan.
24) Add IPVTAP driver (IP-VLAN based tap driver) from Sainath Grandhi.
25) Support GRO in IPSEC protocols, from Steffen Klassert"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1764 commits)
Revert "ath10k: Search SMBIOS for OEM board file extension"
net: socket: fix recvmmsg not returning error from sock_error
bnxt_en: use eth_hw_addr_random()
bpf: fix unlocking of jited image when module ronx not set
arch: add ARCH_HAS_SET_MEMORY config
net: napi_watchdog() can use napi_schedule_irqoff()
tcp: Revert "tcp: tcp_probe: use spin_lock_bh()"
net/hsr: use eth_hw_addr_random()
net: mvpp2: enable building on 64-bit platforms
net: mvpp2: switch to build_skb() in the RX path
net: mvpp2: simplify MVPP2_PRS_RI_* definitions
net: mvpp2: fix indentation of MVPP2_EXT_GLOBAL_CTRL_DEFAULT
net: mvpp2: remove unused register definitions
net: mvpp2: simplify mvpp2_bm_bufs_add()
net: mvpp2: drop useless fields in mvpp2_bm_pool and related code
net: mvpp2: remove unused 'tx_skb' field of 'struct mvpp2_tx_queue'
net: mvpp2: release reference to txq_cpu[] entry after unmapping
net: mvpp2: handle too large value in mvpp2_rx_time_coal_set()
net: mvpp2: handle too large value handling in mvpp2_rx_pkts_coal_set()
net: mvpp2: remove useless arguments in mvpp2_rx_{pkts, time}_coal_set
...
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
iQEcBAABAgAGBQJYrElpAAoJELDendYovxMvNFQH/RJU7lwDSf7rF7ZzFGvdcsfi
T4DDuowkYoJm2+GypoRVzZZ0lxJlxr0mNKPvgGDvuTogMY7pvjAf6B7/xCvTFsNU
UoO2I7ljgXxCXFRiXH50nAjS7PC2PFW3Qx+8XPIWeZmnUPeJi4Q43fiSloUt+a6l
JgS/autOCflGasR5MihCZXkvdVF81K6GuEd3hCh9GKZ/8RiwNPaY50vHnMv/hfqq
SJNRKOTSRXioYlTohLnjuPWHDMayRJEO48IXl3c7aNxDTkHjn78yaoPhJ7m+M0Bq
s2GyaQA4tCwADhP+tilmI5H1vFpt6w9x7O0dgWiSm7TB91lwfZOen2WhTPPp6L8=
=gktV
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.11-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
"Xen features and fixes:
- a series from Boris Ostrovsky adding support for booting Linux as
Xen PVH guest
- a series from Juergen Gross streamlining the xenbus driver
- a series from Paul Durrant adding support for the new device model
hypercall
- several small corrections"
* tag 'for-linus-4.11-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/privcmd: add IOCTL_PRIVCMD_RESTRICT
xen/privcmd: Add IOCTL_PRIVCMD_DM_OP
xen/privcmd: return -ENOTTY for unimplemented IOCTLs
xen: optimize xenbus driver for multiple concurrent xenstore accesses
xen: modify xenstore watch event interface
xen: clean up xenbus internal headers
xenbus: Neaten xenbus_va_dev_error
xen/pvh: Use Xen's emergency_restart op for PVH guests
xen/pvh: Enable CPU hotplug
xen/pvh: PVH guests always have PV devices
xen/pvh: Initialize grant table for PVH guests
xen/pvh: Make sure we don't use ACPI_IRQ_MODEL_PIC for SCI
xen/pvh: Bootstrap PVH guest
xen/pvh: Import PVH-related Xen public interfaces
xen/x86: Remove PVH support
x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C
xen/manage: correct return value check on xenbus_scanf()
x86/xen: Fix APIC id mismatch warning on Intel
xen/netback: set default upper limit of tx/rx queues to 8
xen/netfront: set default upper limit of tx/rx queues to 8
rx_refill_timer should be deleted as soon as we disconnect from the
backend since otherwise it is possible for the timer to go off before
we get to xennet_destroy_queues(). If this happens we may dereference
queue->rx.sring which is set to NULL in xennet_disconnect_backend().
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes a crash when running out of grant refs when creating many
queues across many netdevs.
* If creating queues fails (i.e. there are no grant refs available),
call xenbus_dev_fatal() to ensure that the xenbus device is set to the
closed state.
* If no queues are created, don't call xennet_disconnect_backend as
netdev->real_num_tx_queues will not have been set correctly.
* If setup_netfront() fails, ensure that all the queues created are
cleaned up, not just those that have been set up.
* If any queues were set up and an error occurs, call
xennet_destroy_queues() to clean up the napi context.
* If any fatal error occurs, unregister and destroy the netdev to avoid
leaving around a half setup network device.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The commit 90c311b0ee ("xen-netfront: Fix Rx stall during network
stress and OOM") caused the refill timer to be triggerred almost on
all invocations of xennet_alloc_rx_buffers for certain workloads.
This reworks the fix by reverting to the old behaviour and taking into
consideration the skb allocation failure. Refill timer is now triggered
on insufficient requests or skb allocation failure.
Signed-off-by: Vineeth Remanan Pillai <vineethp@amazon.com>
Fixes: 90c311b0ee (xen-netfront: Fix Rx stall during network stress and OOM)
Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
napi_complete_done() allows to opt-in for gro_flush_timeout,
added back in linux-3.19, commit 3b47d30396
("net: gro: add a per device gro flush timer")
This allows for more efficient GRO aggregation without
sacrifying latencies.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The default for the number of tx/rx queues of one interface is the
number of vcpus of the system today. As each queue pair reserves 512
grant pages this default consumes a ridiculous number of grants for
large guests.
Limit the queue number to 8 as default. This value can be modified
via a module parameter if required.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
During an OOM scenario, request slots could not be created as skb
allocation fails. So the netback cannot pass in packets and netfront
wrongly assumes that there is no more work to be done and it disables
polling. This causes Rx to stall.
The issue is with the retry logic which schedules the timer if the
created slots are less than NET_RX_SLOTS_MIN. The count of new request
slots to be pushed are calculated as a difference between new req_prod
and rsp_cons which could be more than the actual slots, if there are
unconsumed responses.
The fix is to calculate the count of newly created slots as the
difference between new req_prod and old req_prod.
Signed-off-by: Vineeth Remanan Pillai <vineethp@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The network device operation for reading statistics is only called
in one place, and it ignores the return value. Having a structure
return value is potentially confusing because some future driver could
incorrectly assume that the return value was used.
Fix all drivers with ndo_get_stats64 to have a void function.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
iQEcBAABAgAGBQJYT5HMAAoJELDendYovxMvhNQH/1g/3ahM4JKN8Z0SbjKBEdQm
yj2xOj6cE3l6wMSUblKjZD2DLLhpmcHT/E97Xro/lZQEfQJoMXXWWDFowMU/P1LA
mJxb7Fzq5Wr+6eGSAlIQB270MrpNi/luf+CWHMwVA3V7R3KRXwonOdGQSkISIzCd
tgIydEA3a9r2+HgeIBpZFZ4GcSrJQU75krMyl2tjD1C+jeYVd+zdoj2OnDsZQDZQ
hDWApMpNbpSBAn7JtSSdXWSTBsGH0lUECebeYPhPQ2sX2P6Y8+UCGwA7i6FFdbTa
agXfVSdRz8dCe3k19VcKDAw6nK9BTTMnEeEHmkmygIh6wuHPP44CzigTXIbJoXI=
=zjfm
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.10-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
"Xen features and fixes for 4.10
These are some fixes, a move of some arm related headers to share them
between arm and arm64 and a series introducing a helper to make code
more readable.
The most notable change is David stepping down as maintainer of the
Xen hypervisor interface. This results in me sending you the pull
requests for Xen related code from now on"
* tag 'for-linus-4.10-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (29 commits)
xen/balloon: Only mark a page as managed when it is released
xenbus: fix deadlock on writes to /proc/xen/xenbus
xen/scsifront: don't request a slot on the ring until request is ready
xen/x86: Increase xen_e820_map to E820_X_MAX possible entries
x86: Make E820_X_MAX unconditionally larger than E820MAX
xen/pci: Bubble up error and fix description.
xen: xenbus: set error code on failure
xen: set error code on failures
arm/xen: Use alloc_percpu rather than __alloc_percpu
arm/arm64: xen: Move shared architecture headers to include/xen/arm
xen/events: use xen_vcpu_id mapping for EVTCHNOP_status
xen/gntdev: Use VM_MIXEDMAP instead of VM_IO to avoid NUMA balancing
xen-scsifront: Add a missing call to kfree
MAINTAINERS: update XEN HYPERVISOR INTERFACE
xenfs: Use proc_create_mount_point() to create /proc/xen
xen-platform: use builtin_pci_driver
xen-netback: fix error handling output
xen: make use of xenbus_read_unsigned() in xenbus
xen: make use of xenbus_read_unsigned() in xen-pciback
xen: make use of xenbus_read_unsigned() in xen-fbfront
...
Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.
Cc: netdev@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
IS_ERR_VALUE() in commit 87557efc27
("xen-netfront: do not cast grant table reference to signed short") would
not return true for error code unless we cast ref first to type int.
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While grant reference is of type uint32_t, xen-netfront erroneously casts
it to signed short in BUG_ON().
This would lead to the xen domU panic during boot-up or migration when it
is attached with lots of paravirtual devices.
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hyperv_net:
- set min/max_mtu, per Haiyang, after rndis_filter_device_add
virtio_net:
- set min/max_mtu
- remove virtnet_change_mtu
vmxnet3:
- set min/max_mtu
xen-netback:
- min_mtu = 0, max_mtu = 65517
xen-netfront:
- min_mtu = 0, max_mtu = 65535
unisys/visor:
- clean up defines a little to not clash with network core or add
redundat definitions
CC: netdev@vger.kernel.org
CC: virtualization@lists.linux-foundation.org
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: "Michael S. Tsirkin" <mst@redhat.com>
CC: Shrikrishna Khare <skhare@vmware.com>
CC: "VMware, Inc." <pv-drivers@vmware.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Paul Durrant <paul.durrant@citrix.com>
CC: David Kershner <david.kershner@unisys.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Small packet loss is reported on complex multi host network configurations
including tunnels, NAT, ... My investigation led me to the following check
in netback which drops packets:
if (unlikely(txreq.size < ETH_HLEN)) {
netdev_err(queue->vif->dev,
"Bad packet size: %d\n", txreq.size);
xenvif_tx_err(queue, &txreq, extra_count, idx);
break;
}
But this check itself is legitimate. SKBs consist of a linear part (which
has to have the ethernet header) and (optionally) a number of frags.
Netfront transmits the head of the linear part up to the page boundary
as the first request and all the rest becomes frags so when we're
reconstructing the SKB in netback we can't distinguish between original
frags and the 'tail' of the linear part. The first SKB needs to be at
least ETH_HLEN size. So in case we have an SKB with its linear part
starting too close to the page boundary the packet is lost.
I see two ways to fix the issue:
- Change the 'wire' protocol between netfront and netback to start keeping
the original SKB structure. We'll have to add a flag indicating the fact
that the particular request is a part of the original linear part and not
a frag. We'll need to know the length of the linear part to pre-allocate
memory.
- Avoid transmitting SKBs with linear parts starting too close to the page
boundary. That seems preferable short-term and shouldn't bring
significant performance degradation as such packets are rare. That's what
this patch is trying to achieve with skb_copy().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Trying to batch Tx response events results in poor performance because
this delays freeing the transmitted skbs.
Instead use the standard RING_FINAL_CHECK_FOR_RESPONSES() macro to be
notified once the next Tx response is placed on the ring.
Signed-off-by: Malcolm Crossley <malcolm.crossley@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- Improve balloon driver memory hotplug placement.
- Use unpopulated hotplugged memory for foreign pages (if
supported/enabled).
- Support 64 KiB guest pages on arm64.
- CPU hotplug support on arm/arm64.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJWOeSkAAoJEFxbo/MsZsTRph0H/0nE8Tx0GyGtOyCYfBdInTvI
WgjvL8VR1XrweZMVis3668MzhLSYg6b5lvJsoi+L3jlzYRyze43iHXsKfvp+8p0o
TVUhFnlHEHF8ASEtPydAi6HgS7Dn9OQ9LaZ45R1Gk0rHnwJjIQonhTn2jB0yS9Am
Hf4aZXP2NVZphjYcloqNsLH0G6mGLtgq8cS0uKcVO2YIrR4Dr3sfj9qfq9mflf8n
sA/5ifoHRfOUD1vJzYs4YmIBUv270jSsprWK/Mi2oXIxUTBpKRAV1RVCAPW6GFci
HIZjIJkjEPWLsvxWEs0dUFJQGp3jel5h8vFPkDWBYs3+9rILU2DnLWpKGNDHx3k=
=vUfa
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.4-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
- Improve balloon driver memory hotplug placement.
- Use unpopulated hotplugged memory for foreign pages (if
supported/enabled).
- Support 64 KiB guest pages on arm64.
- CPU hotplug support on arm/arm64.
* tag 'for-linus-4.4-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (44 commits)
xen: fix the check of e_pfn in xen_find_pfn_range
x86/xen: add reschedule point when mapping foreign GFNs
xen/arm: don't try to re-register vcpu_info on cpu_hotplug.
xen, cpu_hotplug: call device_offline instead of cpu_down
xen/arm: Enable cpu_hotplug.c
xenbus: Support multiple grants ring with 64KB
xen/grant-table: Add an helper to iterate over a specific number of grants
xen/xenbus: Rename *RING_PAGE* to *RING_GRANT*
xen/arm: correct comment in enlighten.c
xen/gntdev: use types from linux/types.h in userspace headers
xen/gntalloc: use types from linux/types.h in userspace headers
xen/balloon: Use the correct sizeof when declaring frame_list
xen/swiotlb: Add support for 64KB page granularity
xen/swiotlb: Pass addresses rather than frame numbers to xen_arch_need_swiotlb
arm/xen: Add support for 64KB page granularity
xen/privcmd: Add support for Linux 64KB page granularity
net/xen-netback: Make it running on 64KB page granularity
net/xen-netfront: Make it running on 64KB page granularity
block/xen-blkback: Make it running on 64KB page granularity
block/xen-blkfront: Make it running on 64KB page granularity
...
Conflicts:
net/ipv6/xfrm6_output.c
net/openvswitch/flow_netlink.c
net/openvswitch/vport-gre.c
net/openvswitch/vport-vxlan.c
net/openvswitch/vport.c
net/openvswitch/vport.h
The openvswitch conflicts were overlapping changes. One was
the egress tunnel info fix in 'net' and the other was the
vport ->send() op simplification in 'net-next'.
The xfrm6_output.c conflicts was also a simplification
overlapping a bug fix.
Signed-off-by: David S. Miller <davem@davemloft.net>
The PV network protocol is using 4KB page granularity. The goal of this
patch is to allow a Linux using 64KB page granularity using network
device on a non-modified Xen.
It's only necessary to adapt the ring size and break skb data in small
chunk of 4KB. The rest of the code is relying on the grant table code.
Note that we allocate a Linux page for each rx skb but only the first
4KB is used. We may improve the memory usage by extending the size of
the rx skb.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Sometimes xennet_create_queues() may failed to created all requested
queues, we need to update num_queues to real created to avoid NULL
pointer dereference.
Signed-off-by: Joe Jin <joe.jin@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If netfront connects with two (or more) queues and then reconnects with
only one queue it fails to delete or rewrite the multi-queue-num-queues
key and netback will try to use the wrong number of queues.
Always write the num-queues field if the backend has multi-queue support.
Signed-off-by: Chas Williams <3chas3@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- Use the correct GFN/BFN terms more consistently.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJV8VRMAAoJEFxbo/MsZsTRiGQH/i/jrAJUJfrFC2PINaA2gDwe
O0dlrkCiSgAYChGmxxxXZQSPM5Po5+EbT/dLjZ/uvSooeorM9RYY/mFo7ut/qLep
4pyQUuwGtebWGBZTrj9sygUVXVhgJnyoZxskNUbhj9zvP7hb9++IiI78mzne6cpj
lCh/7Z2dgpfRcKlNRu+qpzP79Uc7OqIfDK+IZLrQKlXa7IQDJTQYoRjbKpfCtmMV
BEG3kN9ESx5tLzYiAfxvaxVXl9WQFEoktqe9V8IgOQlVRLgJ2DQWS6vmraGrokWM
3HDOCHtRCXlPhu1Vnrp0R9OgqWbz8FJnmVAndXT8r3Nsjjmd0aLwhJx7YAReO/4=
=JDia
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.3-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen terminology fixes from David Vrabel:
"Use the correct GFN/BFN terms more consistently"
* tag 'for-linus-4.3-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/xenbus: Rename the variable xen_store_mfn to xen_store_gfn
xen/privcmd: Further s/MFN/GFN/ clean-up
hvc/xen: Further s/MFN/GFN clean-up
video/xen-fbfront: Further s/MFN/GFN clean-up
xen/tmem: Use xen_page_to_gfn rather than pfn_to_gfn
xen: Use correctly the Xen memory terminologies
arm/xen: implement correctly pfn_to_mfn
xen: Make clear that swiotlb and biomerge are dealing with DMA address
Originally that parameter was always reset to num_online_cpus during
module initialisation, which renders it useless.
The fix is to only set max_queues to num_online_cpus when user has not
provided a value.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Tested-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This resulted in some misimplementation of helpers on ARM and
confused developers about the expected behavior.
For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.
For clarity and avoid new confusion, replace any reference to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn which may be used by all kind of guests
No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.
Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a
name to close to the KVM function gfn_to_page.
Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up
will come in follow-up patches.
[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
If you simply load and unload the module without starting the interfaces,
the queues are never created and you get a bad pointer dereference.
Signed-off-by: Chas Williams <3chas3@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) mlx4 driver bug fixes (TX queue wakeups, csum complete indications)
from Ido Shamay, Eran Ben Elisha, and Or Gerlitz.
2) Missing unlock in error path of PTP support in renesas driver, from
Dan Carpenter.
3) Add Vitesse 8641 phy IDs to vitesse PHY driver, from Shaohui Xie.
4) Bnx2x driver bug fixes (linearization of encap packets, scratchpad
parity error notifications, flow-control and speed settings) from
Yuval Mintz, Manish Chopra, Shahed Shaikh, and Ariel Elior.
5) ipv6 extension header parsing in the igb chip has a HW errata,
disable it. Frm Todd Fujinaka.
6) Fix PCI link state locking issue in e1000e driver, from Yanir
Lubetkin.
7) Cure panics during MTU change in i40e, from Mitch Williams.
8) Don't leak promisc refs in DSA slave driver, from Gilad Ben-Yossef.
9) Add missing HAS_DMA dep to VIA Rhine driver, from Geery
Uytterhoeven.
10) Make sure DMA map/unmap calls are symmetric in bnx2x driver, from
Michal Schmidt.
11) Workaround for MDIO access problems in bcm7xxx devices, from FLorian
Fainelli.
12) Fix races in SCTP protocol between OTTB responses and route
removals, from Alexander Sverdlin.
13) Fix jumbo frame checksum issue with some mvneta devices, from Simon
Guinot.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (58 commits)
sock_diag: don't broadcast kernel sockets
net: mvneta: disable IP checksum with jumbo frames for Armada 370
ARM: mvebu: update Ethernet compatible string for Armada XP
net: mvneta: introduce compatible string "marvell, armada-xp-neta"
api: fix compatibility of linux/in.h with netinet/in.h
net: icplus: fix typo in constant name
sis900: Trivial: Fix typos in enums
stmmac: Trivial: fix typo in constant name
sctp: Fix race between OOTB responce and route removal
net-Liquidio: Delete unnecessary checks before the function call "vfree"
vmxnet3: Bump up driver version number
amd-xgbe: Add the __GFP_NOWARN flag to Rx buffer allocation
net: phy: mdio-bcm-unimac: workaround initial read failures for integrated PHYs
net: bcmgenet: workaround initial read failures for integrated PHYs
net: phy: bcm7xxx: workaround MDIO management controller initial read
bnx2x: fix DMA API usage
net: via: VIA_RHINE and VIA_VELOCITY should depend on HAS_DMA
net/phy: tune get_phy_c45_ids to support more c45 phy
bnx2x: fix lockdep splat
net: fec: don't access RACC register when not available
...
- Add "make xenconfig" to assist in generating configs for Xen guests.
- Preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests.
- Automatically use hvc0 as the default console in ARM guests.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
iQEcBAABAgAGBQJVkpoqAAoJEFxbo/MsZsTRu3IH/2AMPx2i65hoSqfHtGf3sz/z
XNfcidVmOElFVXGaW83m0tBWMemT5LpOGRfiq5sIo8xt/8xD2vozEkl/3kkf3RrX
EmZDw3E8vmstBdBTjWdovVhNenRc0m0pB5daS7wUdo9cETq1ag1L3BHTB3fEBApO
74V6qAfnhnq+snqWhRD3XAk3LKI0nWuWaV+5HsmxDtnunGhuRLGVs7mwxZGg56sM
mILA0eApGPdwyVVpuDe0SwV52V8E/iuVOWTcomGEN2+cRWffG5+QpHxQA8bOtF6O
KfqldiNXOY/idM+5+oSm9hespmdWbyzsFqmTYz0LvQvxE8eEZtHHB3gIcHkE8QU=
=danz
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
"Xen features and cleanups for 4.2-rc0:
- add "make xenconfig" to assist in generating configs for Xen guests
- preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests
- automatically use hvc0 as the default console in ARM guests"
* tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
block/xen-blkback: s/nr_pages/nr_segs/
block/xen-blkfront: Remove invalid comment
block/xen-blkfront: Remove unused macro MAXIMUM_OUTSTANDING_BLOCK_REQS
arm/xen: Drop duplicate define mfn_to_virt
xen/grant-table: Remove unused macro SPP
xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring
xen: Include xen/page.h rather than asm/xen/page.h
kconfig: add xenconfig defconfig helper
kconfig: clarify kvmconfig is for kvm
xen/pcifront: Remove usage of struct timeval
xen/tmem: use BUILD_BUG_ON() in favor of BUG_ON()
hvc_xen: avoid uninitialized variable warning
xenbus: avoid uninitialized variable warning
xen/arm: allow console=hvc0 to be omitted for guests
arm,arm64/xen: move Xen initialization earlier
arm/xen: Correctly check if the event channel interrupt is present
The function netif_set_real_num_tx_queues() will return -EINVAL if
the second parameter < 1, so call this function with the second
parameter set to 0 is meaningless.
Signed-off-by: Liang Li <liang.z.li@intel.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rx->status is an int16_t, print it using %d rather than %u in order to
have a meaningful value when the field is negative.
Also use %u rather than %x for rx->offset.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Using xen/page.h will be necessary later for using common xen page
helpers.
As xen/page.h already include asm/xen/page.h, always use the later.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: netdev@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Conflicts:
drivers/net/phy/amd-xgbe-phy.c
drivers/net/wireless/iwlwifi/Kconfig
include/net/mac80211.h
iwlwifi/Kconfig and mac80211.h were both trivial overlapping
changes.
The drivers/net/phy/amd-xgbe-phy.c file got removed in 'net-next' and
the bug fix that happened on the 'net' side is already integrated
into the rest of the amd-xgbe driver.
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the timer API function setup_timer instead of structure field
assignments to initialize a timer.
A simplified version of the Coccinelle semantic patch that performs
this transformation is as follows:
@change@
expression e, func, da;
@@
-init_timer (&e);
+setup_timer (&e, func, da);
-e.data = da;
-e.function = func;
Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
xennet_remove() freed the queues before freeing the netdevice which
results in a use-after-free when free_netdev() tries to delete the
napi instances that have already been freed.
Fix this by fully destroy the queues (which includes deleting the napi
instances) before freeing the netdevice.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) Fix verifier memory corruption and other bugs in BPF layer, from
Alexei Starovoitov.
2) Add a conservative fix for doing BPF properly in the BPF classifier
of the packet scheduler on ingress. Also from Alexei.
3) The SKB scrubber should not clear out the packet MARK and security
label, from Herbert Xu.
4) Fix oops on rmmod in stmmac driver, from Bryan O'Donoghue.
5) Pause handling is not correct in the stmmac driver because it
doesn't take into consideration the RX and TX fifo sizes. From
Vince Bridgers.
6) Failure path missing unlock in FOU driver, from Wang Cong.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (44 commits)
net: dsa: use DEVICE_ATTR_RW to declare temp1_max
netns: remove BUG_ONs from net_generic()
IB/ipoib: Fix ndo_get_iflink
sfc: Fix memcpy() with const destination compiler warning.
altera tse: Fix network-delays and -retransmissions after high throughput.
net: remove unused 'dev' argument from netif_needs_gso()
act_mirred: Fix bogus header when redirecting from VLAN
inet_diag: fix access to tcp cc information
tcp: tcp_get_info() should fetch socket fields once
net: dsa: mv88e6xxx: Add missing initialization in mv88e6xxx_set_port_state()
skbuff: Do not scrub skb mark within the same name space
Revert "net: Reset secmark when scrubbing packet"
bpf: fix two bugs in verification logic when accessing 'ctx' pointer
bpf: fix bpf helpers to use skb->mac_header relative offsets
stmmac: Configure Flow Control to work correctly based on rxfifo size
stmmac: Enable unicast pause frame detect in GMAC Register 6
stmmac: Read tx-fifo-depth and rx-fifo-depth from the devicetree
stmmac: Add defines and documentation for enabling flow control
stmmac: Add properties for transmit and receive fifo sizes
stmmac: fix oops on rmmod after assigning ip addr
...
In commit 04ffcb255f ("net: Add ndo_gso_check") Tom originally
added the 'dev' argument to be able to call ndo_gso_check().
Then later, when generalizing this in commit 5f35227ea3
("net: Generalize ndo_gso_check to ndo_features_check")
Jesse removed the call to ndo_gso_check() in netif_needs_gso()
by calling the new ndo_features_check() in a different place.
This made the 'dev' argument unused.
Remove the unused argument and go back to the code as before.
Cc: Tom Herbert <therbert@google.com>
Cc: Jesse Gross <jesse@nicira.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
- Use a single source list of hypercalls, generating other tables
etc. at build time.
- Add a "Xen PV" APIC driver to support >255 VCPUs in PV guests.
- Significant performance improve to guest save/restore/migration.
- scsiback/front save/restore support.
- Infrastructure for multi-page xenbus rings.
- Misc fixes.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
iQEcBAABAgAGBQJVL6OZAAoJEFxbo/MsZsTRs3YH/2AycBHs129DNnc2OLmOklBz
AdD43k+FOfZlv0YU80WmPVmOpGGHGB5Pqkix2KtnvPYmtx3pb/5ikhDwSTWZpqBl
Qq6/RgsRjYZ8VMKqrMTkJMrJWHQYbg8lgsP5810nsFBn/Qdbxms+WBqpMkFVo3b2
rvUZj8QijMJPS3qr55DklVaOlXV4+sTAytTdCiubVnaB/agM2jjRflp/lnJrhtTg
yc4NTrIlD1RsMV/lNh92upBP/pCm6Bs0zQ2H1v3hkdhBBmaO0IVXpSheYhfDOHfo
9v209n137N7X86CGWImFk6m2b+EfiFnLFir07zKSA+iZwkYKn75znSdPfj0KCc0=
=bxTm
-----END PGP SIGNATURE-----
Merge tag 'stable/for-linus-4.1-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen features and fixes from David Vrabel:
- use a single source list of hypercalls, generating other tables etc.
at build time.
- add a "Xen PV" APIC driver to support >255 VCPUs in PV guests.
- significant performance improve to guest save/restore/migration.
- scsiback/front save/restore support.
- infrastructure for multi-page xenbus rings.
- misc fixes.
* tag 'stable/for-linus-4.1-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/pci: Try harder to get PXM information for Xen
xenbus_client: Extend interface to support multi-page ring
xen-pciback: also support disabling of bus-mastering and memory-write-invalidate
xen: support suspend/resume in pvscsi frontend
xen: scsiback: add LUN of restored domain
xen-scsiback: define a pr_fmt macro with xen-pvscsi
xen/mce: fix up xen_late_init_mcelog() error handling
xen/privcmd: improve performance of MMAPBATCH_V2
xen: unify foreign GFN map/unmap for auto-xlated physmap guests
x86/xen/apic: WARN with details.
x86/xen: Provide a "Xen PV" APIC driver to support >255 VCPUs
xen/pciback: Don't print scary messages when unsupported by hypervisor.
xen: use generated hypercall symbols in arch/x86/xen/xen-head.S
xen: use generated hypervisor symbols in arch/x86/xen/trace.c
xen: synchronize include/xen/interface/xen.h with xen
xen: build infrastructure for generating hypercall depending symbols
xen: balloon: Use static attribute groups for sysfs entries
xen: pcpu: Use static attribute groups for sysfs entry
Originally Xen PV drivers only use single-page ring to pass along
information. This might limit the throughput between frontend and
backend.
The patch extends Xenbus driver to support multi-page ring, which in
general should improve throughput if ring is the bottleneck. Changes to
various frontend / backend to adapt to the new interface are also
included.
Affected Xen drivers:
* blkfront/back
* netfront/back
* pcifront/back
* scsifront/back
* vtpmfront
The interface is documented, as before, in xenbus_client.c.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
xen-netfront limits transmitted skbs to be at most 44 segments in size. However,
GSO permits up to 65536 bytes, which means a maximum of 45 segments of 1448
bytes each. This slight reduction in the size of packets means a slight loss in
efficiency.
Since c/s 9ecd1a75d, xen-netfront sets gso_max_size to
XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER,
where XEN_NETIF_MAX_TX_SIZE is 65535 bytes.
The calculation used by tcp_tso_autosize (and also tcp_xmit_size_goal since c/s
6c09fa09d) in determining when to split an skb into two is
sk->sk_gso_max_size - 1 - MAX_TCP_HEADER.
So the maximum permitted size of an skb is calculated to be
(XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER) - 1 - MAX_TCP_HEADER.
Intuitively, this looks like the wrong formula -- we don't need two TCP headers.
Instead, there is no need to deviate from the default gso_max_size of 65536 as
this already accommodates the size of the header.
Currently, the largest skb transmitted by netfront is 63712 bytes (44 segments
of 1448 bytes each), as observed via tcpdump. This patch makes netfront send
skbs of up to 65160 bytes (45 segments of 1448 bytes each).
Similarly, the maximum allowable mtu does not need to subtract MAX_TCP_HEADER as
it relates to the size of the whole packet, including the header.
Fixes: 9ecd1a75d9 ("xen-netfront: reduce gso_max_size to account for max TCP header")
Signed-off-by: Jonathan Davies <jonathan.davies@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
