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.
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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.
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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.
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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.
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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>
Instead of manual calls of device_create_file() and
device_remove_files(), assign the static attribute groups to netdev
groups array. This simplifies the code and avoids the possible
races.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/xen-netfront.c
Minor overlapping changes in xen-netfront.c, mostly to do
with some buffer management changes alongside the split
of stats into TX and RX.
Signed-off-by: David S. Miller <davem@davemloft.net>
Eliminate all the duplicate code for making Tx requests by
consolidating them into a single xennet_make_one_txreq() function.
xennet_make_one_txreq() and xennet_make_txreqs() work with pages and
offsets so it will be easier to make netfront handle highmem frags in
the future.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A function to count the number of slots an skb needs is more useful
than one that counts the slots needed for only the frags.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In netfront the Rx and Tx path are independent and use different
locks. The Tx lock is held with hard irqs disabled, but Rx lock is
held with only BH disabled. Since both sides use the same stats lock,
a deadlock may occur.
[ INFO: possible irq lock inversion dependency detected ]
3.16.2 #16 Not tainted
---------------------------------------------------------
swapper/0/0 just changed the state of lock:
(&(&queue->tx_lock)->rlock){-.....}, at: [<c03adec8>]
xennet_tx_interrupt+0x14/0x34
but this lock took another, HARDIRQ-unsafe lock in the past:
(&stat->syncp.seq#2){+.-...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&stat->syncp.seq#2);
local_irq_disable();
lock(&(&queue->tx_lock)->rlock);
lock(&stat->syncp.seq#2);
<Interrupt>
lock(&(&queue->tx_lock)->rlock);
Using separate locks for the Rx and Tx stats fixes this deadlock.
Reported-by: Dmitry Piotrovsky <piotrovskydmitry@gmail.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes some unused arrays from the netfront private
data structures. These arrays were used in "flip" receive mode.
Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After d75b1ade56 (net: less interrupt
masking in NAPI) the napi instance is removed from the per-cpu list
prior to calling the n->poll(), and is only requeued if all of the
budget was used. This inadvertently broke netfront because netfront
does not use NAPI correctly.
If netfront had not used all of its budget it would do a final check
for any Rx responses and avoid calling napi_complete() if there were
more responses. It would still return under budget so it would never
be rescheduled. The final check would also not re-enable the Rx
interrupt.
Additionally, xenvif_poll() would also call napi_complete() /after/
enabling the interrupt. This resulted in a race between the
napi_complete() and the napi_schedule() in the interrupt handler. The
use of local_irq_save/restore() avoided by race iff the handler is
running on the same CPU but not if it was running on a different CPU.
Fix both of these by always calling napi_compete() if the budget was
not all used, and then calling napi_schedule() if the final checks
says there's more work.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conflicts:
drivers/net/ethernet/amd/xgbe/xgbe-desc.c
drivers/net/ethernet/renesas/sh_eth.c
Overlapping changes in both conflict cases.
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 97a6d1bb2b (xen-netfront: Fix
handling packets on compound pages with skb_linearize) attempted to
fix a problem where an skb that would have required too many slots
would be dropped causing TCP connections to stall.
However, it filled in the first slot using the original buffer and not
the new one and would use the wrong offset and grant access to the
wrong page.
Netback would notice the malformed request and stop all traffic on the
VIF, reporting:
vif vif-3-0 vif3.0: txreq.offset: 85e, size: 4002, end: 6144
vif vif-3-0 vif3.0: fatal error; disabling device
Reported-by: Anthony Wright <anthony@overnetdata.com>
Tested-by: Anthony Wright <anthony@overnetdata.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These BUGs can be erroneously triggered by frags which refer to
tail pages within a compound page. The data in these pages may
overrun the hardware page while still being contained within the
compound page, but since compound_order() evaluates to 0 for tail
pages the assertion fails. The code already iterates through
subsequent pages correctly in this scenario, so the BUGs are
unnecessary and can be removed.
Fixes: f36c374782 ("xen/netfront: handle compound page fragments on transmit")
Cc: <stable@vger.kernel.org> # 3.7+
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A full Rx ring only requires 1 MiB of memory. This is not enough
memory that it is useful to dynamically scale the number of Rx
requests in the ring based on traffic rates, because:
a) Even the full 1 MiB is a tiny fraction of a typically modern Linux
VM (for example, the AWS micro instance still has 1 GiB of memory).
b) Netfront would have used up to 1 MiB already even with moderate
data rates (there was no adjustment of target based on memory
pressure).
c) Small VMs are going to typically have one VCPU and hence only one
queue.
Keeping the ring full of Rx requests handles bursty traffic better
than trying to converge on an optimal number of requests to keep
filled.
On a 4 core host, an iperf -P 64 -t 60 run from dom0 to a 4 VCPU guest
improved from 5.1 Gbit/s to 5.6 Gbit/s. Gains with more bursty
traffic are expected to be higher.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) Include fixes for netrom and dsa (Fabian Frederick and Florian
Fainelli)
2) Fix FIXED_PHY support in stmmac, from Giuseppe CAVALLARO.
3) Several SKB use after free fixes (vxlan, openvswitch, vxlan,
ip_tunnel, fou), from Li ROngQing.
4) fec driver PTP support fixes from Luwei Zhou and Nimrod Andy.
5) Use after free in virtio_net, from Michael S Tsirkin.
6) Fix flow mask handling for megaflows in openvswitch, from Pravin B
Shelar.
7) ISDN gigaset and capi bug fixes from Tilman Schmidt.
8) Fix route leak in ip_send_unicast_reply(), from Vasily Averin.
9) Fix two eBPF JIT bugs on x86, from Alexei Starovoitov.
10) TCP_SKB_CB() reorganization caused a few regressions, fixed by Cong
Wang and Eric Dumazet.
11) Don't overwrite end of SKB when parsing malformed sctp ASCONF
chunks, from Daniel Borkmann.
12) Don't call sock_kfree_s() with NULL pointers, this function also has
the side effect of adjusting the socket memory usage. From Cong Wang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (90 commits)
bna: fix skb->truesize underestimation
net: dsa: add includes for ethtool and phy_fixed definitions
openvswitch: Set flow-key members.
netrom: use linux/uaccess.h
dsa: Fix conversion from host device to mii bus
tipc: fix bug in bundled buffer reception
ipv6: introduce tcp_v6_iif()
sfc: add support for skb->xmit_more
r8152: return -EBUSY for runtime suspend
ipv4: fix a potential use after free in fou.c
ipv4: fix a potential use after free in ip_tunnel_core.c
hyperv: Add handling of IP header with option field in netvsc_set_hash()
openvswitch: Create right mask with disabled megaflows
vxlan: fix a free after use
openvswitch: fix a use after free
ipv4: dst_entry leak in ip_send_unicast_reply()
ipv4: clean up cookie_v4_check()
ipv4: share tcp_v4_save_options() with cookie_v4_check()
ipv4: call __ip_options_echo() in cookie_v4_check()
atm: simplify lanai.c by using module_pci_driver
...
Add ndo_gso_check which a device can define to indicate whether is
is capable of doing GSO on a packet. This funciton would be called from
the stack to determine whether software GSO is needed to be done. A
driver should populate this function if it advertises GSO types for
which there are combinations that it wouldn't be able to handle. For
instance a device that performs UDP tunneling might only implement
support for transparent Ethernet bridging type of inner packets
or might have limitations on lengths of inner headers.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The DEFINE_XENBUS_DRIVER() macro looks a bit weird and causes sparse
errors.
Replace the uses with standard structure definitions instead. This is
similar to pci and usb device registration.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
There is a long known problem with the netfront/netback interface: if the guest
tries to send a packet which constitues more than MAX_SKB_FRAGS + 1 ring slots,
it gets dropped. The reason is that netback maps these slots to a frag in the
frags array, which is limited by size. Having so many slots can occur since
compound pages were introduced, as the ring protocol slice them up into
individual (non-compound) page aligned slots. The theoretical worst case
scenario looks like this (note, skbs are limited to 64 Kb here):
linear buffer: at most PAGE_SIZE - 17 * 2 bytes, overlapping page boundary,
using 2 slots
first 15 frags: 1 + PAGE_SIZE + 1 bytes long, first and last bytes are at the
end and the beginning of a page, therefore they use 3 * 15 = 45 slots
last 2 frags: 1 + 1 bytes, overlapping page boundary, 2 * 2 = 4 slots
Although I don't think this 51 slots skb can really happen, we need a solution
which can deal with every scenario. In real life there is only a few slots
overdue, but usually it causes the TCP stream to be blocked, as the retry will
most likely have the same buffer layout.
This patch solves this problem by linearizing the packet. This is not the
fastest way, and it can fail much easier as it tries to allocate a big linear
area for the whole packet, but probably easier by an order of magnitude than
anything else. Probably this code path is not touched very frequently anyway.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Paul Durrant <paul.durrant@citrix.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Signed-off-by: David S. Miller <davem@davemloft.net>
When less than the requested number of queues could be created, include
the actual number in the warning (instead of the requested number).
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since netfront may reconnect to a backend with a different number of
queues, all per-queue Rx and Tx resources (skbs and grant references)
should be freed when disconnecting.
Without this fix, the Tx and Rx grant refs are not released and
netfront will exhaust them after only a few reconnections. netfront
will fail to connect when no free grant references are available.
Since all Rx bufs are freed and reallocated instead of reused this
will add some additional delay to the reconnection but this is
expected to be small compared to the time taken by any backend hotplug
scripts etc.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If no queues could be created when connecting to the backend, one of the
error paths would deadlock.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In xennet_disconnect_backend(), netif_carrier_off() was called once
per queue when it needs to only be called once.
The queue locking around the netif_carrier_off() call looked very
odd. I think they were supposed to synchronize any NAPI instances with
the expectation that no further NAPI instances would be scheduled
because of the carrier being off (see the check in
xennet_rx_interrupt()). But I can't easily tell if this works
correctly.
Instead, add a napi_synchronize() call after disabling the interrupts.
This is obviously correct as with no Rx interrupts, no further NAPI
instances will be scheduled.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The nesting of the per-queue rx_lock and tx_lock in xennet_connect()
is confusing to both humans and lockdep. The locking is safe because
this is the only place where the locks are nested in this way but
lockdep still warns.
Instead of adding the missing lockdep annotations, refactor the
locking to avoid the confusing nesting. This is still safe, because
the xenbus connection state changes are all serialized by the xenwatch
thread.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: David S. Miller <davem@davemloft.net>
When reconnecting to the backend (after a resume/migration, for example),
a different number of queues may be required (since the guest may have
moved to a different host with different capabilities). During the
reconnection the old queues are torn down and new ones created.
Introduce xennet_create_queues() and xennet_destroy_queues() that fixes
three bugs during the reconnection.
- The old info->queues was leaked.
- The old queue's napi instances were not deleted.
- The new queue's napi instances were left disabled (which meant no
packets could be received).
The xennet_destroy_queues() calls is deferred until the reconnection
instead of the disconnection (in xennet_disconnect_backend()) because
napi_disable() might sleep.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
xennet_disconnect_backend() was not correctly iterating over all the
queues.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Build on the refactoring of the previous patch to implement multiple
queues between xen-netfront and xen-netback.
Check XenStore for multi-queue support, and set up the rings and event
channels accordingly.
Write ring references and event channels to XenStore in a queue
hierarchy if appropriate, or flat when using only one queue.
Update the xennet_select_queue() function to choose the queue on which
to transmit a packet based on the skb hash result.
Signed-off-by: Andrew J. Bennieston <andrew.bennieston@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In preparation for multi-queue support in xen-netfront, move the
queue-specific data from struct netfront_info to struct netfront_queue,
and update the rest of the code to use this.
Also adds loops over queues where appropriate, even though only one is
configured at this point, and uses alloc_etherdev_mq() and the
corresponding multi-queue netif wake/start/stop functions in preparation
for multiple active queues.
Finally, implements a trivial queue selection function suitable for
ndo_select_queue, which simply returns 0, selecting the first (and
only) queue.
Signed-off-by: Andrew J. Bennieston <andrew.bennieston@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vitaly Kuznetsov