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path: root/drivers/net/virtio_net.c
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2009-04-04virtio_net: Set the mac config only when VIRITO_NET_F_MACAlex Williamson
VIRTIO_NET_F_MAC indicates the presence of the mac field in config space, not the validity of the value it contains. Allow the mac to be changed at runtime, but only push the change into config space with the VIRTIO_NET_F_MAC feature present. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-20Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/virtio_net.c
2009-03-18virtio_net: Make virtio_net support carrier detectionPantelis Koukousoulas
Impact: Make NetworkManager work with virtio_net For now the semantics are simple: There is always carrier. This allows a seamless experience with e.g., qemu/kvm where NetworkManager just configures and sets up everything automagically. If/when a generally agreed-upon way to control carrier on/off in the emulator/hypervisor level emerges, it will be trivial to extend the driver to support that too, but for now even this 2-liner makes user experience that much better. Signed-off-by: Pantelis Koukousoulas <pktoss@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-04virtio_net: Allow setting the MAC address of the NICAlex Williamson
Many physical NICs let the OS re-program the "hardware" MAC address. Virtual NICs should allow this too. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-04virtio_net: Add support for VLAN filtering in the hypervisorAlex Williamson
VLAN filtering allows the hypervisor to drop packets from VLANs that we're not a part of, further reducing the number of extraneous packets recieved. This makes use of the VLAN virtqueue command class. The CTRL_VLAN feature bit tells us whether the backend supports VLAN filtering. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-04virtio_net: Add a MAC filter tableAlex Williamson
Make use of the MAC control virtqueue class to support a MAC filter table. The filter table is managed by the hypervisor. We consider the table to be available if the CTRL_RX feature bit is set. We leave it to the hypervisor to manage the table and enable promiscuous or all-multi mode as necessary depending on the resources available to it. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-04virtio_net: Add a set_rx_mode interfaceAlex Williamson
Make use of the RX_MODE control virtqueue class to enable the set_rx_mode netdev interface. This allows us to selectively enable/disable promiscuous and allmulti mode so we don't see packets we don't want. For now, we automatically enable these as needed if additional unicast or multicast addresses are requested. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-04virtio_net: Add a virtqueue for outbound control commandsAlex Williamson
This will be used for RX mode, MAC filter table, VLAN filtering, etc... The control transaction consists of one or more "out" sg entries and one or more "in" sg entries. The first out entry contains a header defining the class and command. Additional out entries may provide data for the command. The last in entry provides a status response back from the command. Virtqueues typically run asynchronous, running a callback function when there's data in the channel. We can't readily make use of this in the command paths where we need to use this. Instead, we kick the virtqueue and spin. The kick causes an I/O write, triggering an immediate trap into the hypervisor. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-30Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/e1000/e1000_main.c
2009-01-26virtio_net: use correct accessors for scatterlistsIra W. Snyder
Without this fix, virtio_net makes incorrect usage of scatterlists. It sets the end of the scatterlist chain after the first element, despite the fact that more entries come after it. If you try to run dma_map_sg() on one of the scatterlists given to you by add_buf(), you will get a null pointer oops. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-26Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
2009-01-25virtio_net: Fix MAX_PACKET_LEN to support 802.1Q VLANsAlex Williamson
802.1Q expanded the maximum ethernet frame size by 4 bytes for the VLAN tag. We're not taking this into account in virtio_net, which means the buffers we provide to the backend in the virtqueue RX ring aren't big enough to hold a full MTU VLAN packet. For QEMU/KVM, this results in the backend exiting with a packet truncation error. Signed-off-by: Alex Williamson <alex.williamson@hp.com> Acked-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-21virtio_net: add link status handlingMark McLoughlin
Allow the host to inform us that the link is down by adding a VIRTIO_NET_F_STATUS which indicates that device status is available in virtio_net config. This is currently useful for simulating link down conditions (e.g. using proposed qemu 'set_link' monitor command) but would also be needed if we were to support device assignment via virtio. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (added future masking) Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-21net: Remove redundant NAPI functionsBen Hutchings
Following the removal of the unused struct net_device * parameter from the NAPI functions named *netif_rx_* in commit 908a7a1, they are exactly equivalent to the corresponding *napi_* functions and are therefore redundant. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-01-06virtio: convert to net_device_opsStephen Hemminger
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Acked-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-22net: Remove unused netdev arg from some NAPI interfaces.Neil Horman
When the napi api was changed to separate its 1:1 binding to the net_device struct, the netif_rx_[prep|schedule|complete] api failed to remove the now vestigual net_device structure parameter. This patch cleans up that api by properly removing it.. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-02virtio_net: large tx MTU supportMark McLoughlin
We don't really have a max tx packet size limit, so allow configuring the device with up to 64k tx MTU. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-11-16virtio_net: VIRTIO_NET_F_MSG_RXBUF (imprive rcv buffer allocation)Mark McLoughlin
If segmentation offload is enabled by the host, we currently allocate maximum sized packet buffers and pass them to the host. This uses up 20 ring entries, allowing us to supply only 20 packet buffers to the host with a 256 entry ring. This is a huge overhead when receiving small packets, and is most keenly felt when receiving MTU sized packets from off-host. The VIRTIO_NET_F_MRG_RXBUF feature flag is set by hosts which support using receive buffers which are smaller than the maximum packet size. In order to transfer large packets to the guest, the host merges together multiple receive buffers to form a larger logical buffer. The number of merged buffers is returned to the guest via a field in the virtio_net_hdr. Make use of this support by supplying single page receive buffers to the host. On receive, we extract the virtio_net_hdr, copy 128 bytes of the payload to the skb's linear data buffer and adjust the fragment offset to point to the remaining data. This ensures proper alignment and allows us to not use any paged data for small packets. If the payload occupies multiple pages, we simply append those pages as fragments and free the associated skbs. This scheme allows us to be efficient in our use of ring entries while still supporting large packets. Benchmarking using netperf from an external machine to a guest over a 10Gb/s network shows a 100% improvement from ~1Gb/s to ~2Gb/s. With a local host->guest benchmark with GSO disabled on the host side, throughput was seen to increase from 700Mb/s to 1.7Gb/s. Based on a patch from Herbert Xu. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (use netdev_priv) Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-16virtio_net: hook up the set-tso ethtool opMark McLoughlin
Seems like an oversight that we have set-tx-csum and set-sg hooked up, but not set-tso. Also leads to the strange situation that if you e.g. disable tx-csum, then tso doesn't get disabled. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-16virtio_net: Recycle some more rx buffer pagesMark McLoughlin
Each time we re-fill the recv queue with buffers, we allocate one too many skbs and free it again when adding fails. We should recycle the pages allocated in this case. A previous version of this patch made trim_pages() trim trailing unused pages from skbs with some paged data, but this actually caused a barely measurable slowdown. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (use netdev_priv) Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-12netdevice: safe convert to netdev_priv() #part-3Wang Chen
We have some reasons to kill netdev->priv: 1. netdev->priv is equal to netdev_priv(). 2. netdev_priv() wraps the calculation of netdev->priv's offset, obviously netdev_priv() is more flexible than netdev->priv. But we cann't kill netdev->priv, because so many drivers reference to it directly. This patch is a safe convert for netdev->priv to netdev_priv(netdev). Since all of the netdev->priv is only for read. But it is too big to be sent in one mail. I split it to 4 parts and make every part smaller than 100,000 bytes, which is max size allowed by vger. Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-27net: convert print_mac to %pMJohannes Berg
This converts pretty much everything to print_mac. There were a few things that had conflicts which I have just dropped for now, no harm done. I've built an allyesconfig with this and looked at the files that weren't built very carefully, but it's a huge patch. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-25virtio: Recycle unused recv buffer pages for large skbs in net driverRusty Russell
If we hack the virtio_net driver to always allocate full-sized (64k+) skbuffs, the driver slows down (lguest numbers): Time to receive 1GB (small buffers): 10.85 seconds Time to receive 1GB (64k+ buffers): 24.75 seconds Of course, large buffers use up more space in the ring, so we increase that from 128 to 2048: Time to receive 1GB (64k+ buffers, 2k ring): 16.61 seconds If we recycle pages rather than using alloc_page/free_page: Time to receive 1GB (64k+ buffers, 2k ring, recycle pages): 10.81 seconds This demonstrates that with efficient allocation, we don't need to have a separate "small buffer" queue. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-07-25virtio net: Allow receiving SG packetsHerbert Xu
Finally this patch lets virtio_net receive GSO packets in addition to sending them. This can definitely be optimised for the non-GSO case. For comparison the Xen approach stores one page in each skb and uses subsequent skb's pages to construct an SG skb instead of preallocating the maximum amount of pages per skb. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (added feature bits)
2008-07-25virtio net: Add ethtool ops for SG/GSOHerbert Xu
This patch adds some basic ethtool operations to virtio_net so I could test SG without GSO (which was really useful because TSO turned out to be buggy :) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (remove MTU setting)
2008-07-25virtio: fix virtio_net xmit of freed skb bugMark McLoughlin
On Mon, 2008-05-26 at 17:42 +1000, Rusty Russell wrote: > If we fail to transmit a packet, we assume the queue is full and put > the skb into last_xmit_skb. However, if more space frees up before we > xmit it, we loop, and the result can be transmitting the same skb twice. > > Fix is simple: set skb to NULL if we've used it in some way, and check > before sending. ... > diff -r 564237b31993 drivers/net/virtio_net.c > --- a/drivers/net/virtio_net.c Mon May 19 12:22:00 2008 +1000 > +++ b/drivers/net/virtio_net.c Mon May 19 12:24:58 2008 +1000 > @@ -287,21 +287,25 @@ again: > free_old_xmit_skbs(vi); > > /* If we has a buffer left over from last time, send it now. */ > - if (vi->last_xmit_skb) { > + if (unlikely(vi->last_xmit_skb)) { > if (xmit_skb(vi, vi->last_xmit_skb) != 0) { > /* Drop this skb: we only queue one. */ > vi->dev->stats.tx_dropped++; > kfree_skb(skb); > + skb = NULL; > goto stop_queue; > } > vi->last_xmit_skb = NULL; With this, may drop an skb and then later in the function discover that we could have sent it after all. Poor wee skb :) How about the incremental patch below? Cheers, Mark. Subject: [PATCH] virtio_net: Delay dropping tx skbs Currently we drop the skb in start_xmit() if we have a queued buffer and fail to transmit it. However, if we delay dropping it until we've stopped the queue and enabled the tx notification callback, then there is a chance space might become available for it. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-07-11virtio_net: Set VIRTIO_NET_F_GUEST_CSUM featureMark McLoughlin
We can handle receiving partial csums, so set the appropriate feature bit. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-06-10virtio: use callback on empty in virtio_netRusty Russell
virtio_net uses a timer to free old transmitted packets, rather than leaving callbacks enabled all the time. If the host promises to always notify us when the transmit ring is empty, we can free packets at that point and avoid the timer. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-06-10virtio: virtio_net free transmit skbs in a timerMark McLoughlin
virtio_net currently only frees old transmit skbs just before queueing new ones. If the queue is full, it then enables interrupts and waits for notification that more work has been performed. However, a side-effect of this scheme is that there are always xmit skbs left dangling when no new packets are sent, against the Documentation/networking/driver.txt guideline: "... it is not allowed for your TX mitigation scheme to let TX packets "hang out" in the TX ring unreclaimed forever if no new TX packets are sent." Add a timer to ensure that any time we queue new TX skbs, we will shortly free them again. This fixes an easily reproduced hang at shutdown where iptables attempts to unload nf_conntrack and nf_conntrack waits for an skb it is tracking to be freed, but virtio_net never frees it. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-06-10virtio_net: Fix skb->csum_start computationMark McLoughlin
hdr->csum_start is the offset from the start of the ethernet header to the transport layer checksum field. skb->csum_start is the offset from skb->head. skb_partial_csum_set() assumes that skb->data points to the ethernet header - i.e. it computes skb->csum_start by adding the headroom to hdr->csum_start. Since eth_type_trans() skb_pull()s the ethernet header, skb_partial_csum_set() should be called before eth_type_trans(). (Without this patch, GSO packets from a guest to the world outside the host are corrupted). Signed-off-by: Mark McLoughlin <markmc@redhat.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-30virtio: fix delayed xmit of packet and freeing of old packets.Rusty Russell
Because we cache the last failed-to-xmit packet, if there are no packets queued behind that one we may never send it (reproduced here as TCP stalls, "cured" by an outgoing ping). Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-30virtio: fix virtio_net xmit of freed skb bugRusty Russell
If we fail to transmit a packet, we assume the queue is full and put the skb into last_xmit_skb. However, if more space frees up before we xmit it, we loop, and the result can be transmitting the same skb twice. Fix is simple: set skb to NULL if we've used it in some way, and check before sending. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-22VIRTIO: Use __skb_queue_purge()Wang Chen
Use standard routine for queue purging. Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-05-02virtio: explicit advertisement of driver featuresRusty Russell
A recent proposed feature addition to the virtio block driver revealed some flaws in the API: in particular, we assume that feature negotiation is complete once a driver's probe function returns. There is nothing in the API to require this, however, and even I didn't notice when it was violated. So instead, we require the driver to specify what features it supports in a table, we can then move the feature negotiation into the virtio core. The intersection of device and driver features are presented in a new 'features' bitmap in the struct virtio_device. Note that this highlights the difference between Linux unsigned-long bitmaps where each unsigned long is in native endian, and a straight-forward little-endian array of bytes. Drivers can still remove feature bits in their probe routine if they really have to. API changes: - dev->config->feature() no longer gets and acks a feature. - drivers should advertise their features in the 'feature_table' field - use virtio_has_feature() for extra sanity when checking feature bits Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-02virtio: finer-grained features for virtio_netRusty Russell
So, we previously had a 'VIRTIO_NET_F_GSO' bit which meant that 'the host can handle csum offload, and any TSO (v4&v6 incl ECN) or UFO packets you might want to send. I thought this was good enough for Linux, but it actually isn't, since we don't do UFO in software. So, add separate feature bits for what the host can handle. Add equivalent ones for the guest to say what it can handle, because LRO is coming too (thanks Herbert!). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-02virtio: wean net driver off NETDEV_TX_BUSYRusty Russell
Herbert tells me that returning NETDEV_TX_BUSY from hard_start_xmit is seen as a poor thing to do; we should cache the packet and stop the queue. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
2008-05-02virtio: fix scatterlist sizing in net driver.Rusty Russell
Herbert Xu points out (within another patch) that my scatterlists are too short: one entry for the gso header, one for the skb->data, and MAX_SKB_FRAGS for all the fragments. Fix both xmit and recv sides (recv currently unused, coming in later patch). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-02virtio: fix tx_ stats in virtio_netRusty Russell
get_buf() gives the length written by the other side, which will be zero. We want to add the skb length. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-04-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: [NETNS][IPV6] tcp - assign the netns for timewait sockets [IPV4]: Fix byte value boundary check in do_ip_getsockopt(). BNX2X: Correct bringing chip out of reset [NETFILTER]: nf_nat: autoload IPv4 connection tracking [NETFILTER]: xt_hashlimit: fix mask calculation [XFRM]: xfrm_user: fix selector family initialization rt61pci: rt61pci_beacon_update do not free skb twice ssb-mipscore: Fix interrupt vectors ssb-pcicore: Fix IRQ TPS flag handling mac80211: use short_preamble mode from capability if ERP IE not present [NET]: Undo code bloat in hot paths due to print_mac(). [TCP]: Don't allow FRTO to take place while MTU is being probed [TCP]: tcp_simple_retransmit can cause S+L [TCP]: Fix NewReno's fast rexmit/recovery problems with GSOed skb [TCP]: Restore 2.6.24 mark_head_lost behavior for newreno/fack nl80211: fix STA AID bug b43legacy: fix bcm4303 crash iwlwifi: fix n-band association problem ipw2200: set MAC address on radiotap interface libertas: fix mode initialization problem
2008-04-08[NET]: Undo code bloat in hot paths due to print_mac().David S. Miller
If print_mac() is used inside of a pr_debug() the compiler can't see that the call is redundant so still performs it even of pr_debug() ends up being a nop. So don't use print_mac() in such cases in hot code paths, use MAC_FMT et al. instead. As noted by Joe Perches, pr_debug() could be modified to handle this better, but that is a change to an interface used by the entire kernel and thus needs to be validated carefully. This here is thus the less risky fix for 2.6.25 Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-07virtio_net: remove overzealous printkAnthony Liguori
The 'disable_cb' is really just a hint and as such, it's possible for more work to get queued up while callbacks are disabled. Under stress with an SMP guest, this printk triggers very frequently. There is no race here, this is how things are designed to work so let's just remove the printk. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-17virtio: fix race in enable_cbChristian Borntraeger
There is a race in virtio_net, dealing with disabling/enabling the callback. I saw the following oops: kernel BUG at /space/kvm/drivers/virtio/virtio_ring.c:218! illegal operation: 0001 [#1] SMP Modules linked in: sunrpc dm_mod CPU: 2 Not tainted 2.6.25-rc1zlive-host-10623-gd358142-dirty #99 Process swapper (pid: 0, task: 000000000f85a610, ksp: 000000000f873c60) Krnl PSW : 0404300180000000 00000000002b81a6 (vring_disable_cb+0x16/0x20) R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:3 PM:0 EA:3 Krnl GPRS: 0000000000000001 0000000000000001 0000000010005800 0000000000000001 000000000f3a0900 000000000f85a610 0000000000000000 0000000000000000 0000000000000000 000000000f870000 0000000000000000 0000000000001237 000000000f3a0920 000000000010ff74 00000000002846f6 000000000fa0bcd8 Krnl Code: 00000000002b819a: a7110001 tmll %r1,1 00000000002b819e: a7840004 brc 8,2b81a6 00000000002b81a2: a7f40001 brc 15,2b81a4 >00000000002b81a6: a51b0001 oill %r1,1 00000000002b81aa: 40102000 sth %r1,0(%r2) 00000000002b81ae: 07fe bcr 15,%r14 00000000002b81b0: eb7ff0380024 stmg %r7,%r15,56(%r15) 00000000002b81b6: a7f13e00 tmll %r15,15872 Call Trace: ([<000000000fa0bcd0>] 0xfa0bcd0) [<00000000002b8350>] vring_interrupt+0x5c/0x6c [<000000000010ab08>] do_extint+0xb8/0xf0 [<0000000000110716>] ext_no_vtime+0x16/0x1a [<0000000000107e72>] cpu_idle+0x1c2/0x1e0 The problem can be triggered with a high amount of host->guest traffic. I think its the following race: poll says netif_rx_complete poll calls enable_cb enable_cb opens the interrupt mask a new packet comes, an interrupt is triggered----\ enable_cb sees that there is more work | enable_cb disables the interrupt | . V . interrupt is delivered . skb_recv_done does atomic napi test, ok some waiting disable_cb is called->check fails->bang! . poll would do napi check poll would do disable_cb The fix is to let enable_cb not disable the interrupt again, but expect the caller to do the cleanup if it returns false. In that case, the interrupt is only disabled, if the napi test_set_bit was successful. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cleaned up doco)
2008-03-17virtio: Enable netpoll interface for netconsole loggingAmit Shah
Add a new poll_controller handler that the netpoll interface needs. This enables netconsole logging from a kvm guest over the virtio net interface. Signed-off-by: Amit Shah <amitshah@gmx.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-23virtio_net: Fix oops on early interrupts - introduced by virtio reset codeChristian Borntraeger
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2008-02-06virtio net: fix oops on interface-upChristian Borntraeger
I got the following oops during interface ifup. Unfortunately its not easily reproducable so I cant say for sure that my fix fixes this problem, but I am confident and I think its correct anyway: <2>kernel BUG at /space/kvm/drivers/virtio/virtio_ring.c:234! <4>illegal operation: 0001 [#1] PREEMPT SMP <4>Modules linked in: <4>CPU: 0 Not tainted 2.6.24zlive-guest-07293-gf1ca151-dirty #91 <4>Process swapper (pid: 0, task: 0000000000800938, ksp: 000000000084ddb8) <4>Krnl PSW : 0404300180000000 0000000000466374 (vring_disable_cb+0x30/0x34) <4> R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:3 PM:0 EA:3 <4>Krnl GPRS: 0000000000000001 0000000000000001 0000000010003800 0000000000466344 <4> 000000000e980900 00000000008848b0 000000000084e748 0000000000000000 <4> 000000000087b300 0000000000001237 0000000000001237 000000000f85bdd8 <4> 000000000e980920 00000000001137c0 0000000000464754 000000000f85bdd8 <4>Krnl Code: 0000000000466368: e3b0b0700004 lg %r11,112(%r11) <4> 000000000046636e: 07fe bcr 15,%r14 <4> 0000000000466370: a7f40001 brc 15,466372 <4> >0000000000466374: a7f4fff6 brc 15,466360 <4> 0000000000466378: eb7ff0500024 stmg %r7,%r15,80(%r15) <4> 000000000046637e: a7f13e00 tmll %r15,15872 <4> 0000000000466382: b90400ef lgr %r14,%r15 <4> 0000000000466386: a7840001 brc 8,466388 <4>Call Trace: <4>([<000201500f85c000>] 0x201500f85c000) <4> [<0000000000466556>] vring_interrupt+0x72/0x88 <4> [<00000000004801a0>] kvm_extint_handler+0x34/0x44 <4> [<000000000010d22c>] do_extint+0xbc/0xf8 <4> [<0000000000113f98>] ext_no_vtime+0x16/0x1a <4> [<000000000010a182>] cpu_idle+0x216/0x238 <4>([<000000000010a162>] cpu_idle+0x1f6/0x238) <4> [<0000000000568656>] rest_init+0xaa/0xb8 <4> [<000000000084ee2c>] start_kernel+0x3fc/0x490 <4> [<0000000000100020>] _stext+0x20/0x80 <4> <4> <0>Kernel panic - not syncing: Fatal exception in interrupt <4> After looking at the code and the dump I think the following scenario happened: Ifup was running on cpu2 and the interrupt arrived on cpu0. Now virtnet_open on cpu 2 managed to execute napi_enable and disable_cb but did not execute rx_schedule. Meanwhile on cpu 0 skb_recv_done was called by vring_interrupt, executed netif_rx_schedule_prep, which succeeded and therefore called disable_cb. This triggered the BUG_ON, as interrupts were already disabled by cpu 2. I think the proper solution is to make the call to disable_cb depend on the atomic update of NAPI_STATE_SCHED by using netif_rx_schedule_prep in the same way as skb_recv_done. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2008-02-04virtio_net: parametrize the napi_weight for virtio receive queue.Dor Laor
It is done in order to improve performance. Signed-off-by: Dor Laor <dor.laor@qumranet.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtio: free transmit skbs when notified, not on next xmit.Rusty Russell
This fixes a potential dangling xmit problem. We also suppress refill interrupts until we need them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtio: flush buffers on openRusty Russell
Fix bug found by Christian Borntraeger: if the other side fills all the registered network buffers before we enable NAPI, we will never get an interrupt. The simplest fix is to process the input queue once on open. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtnet: remove double ether_setupChristian Borntraeger
Hello Rusty, virtnet_probe already calls alloc_etherdev, which calls ether_setup. There is no need to do that again. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtio: reset functionRusty Russell
A reset function solves three problems: 1) It allows us to renegotiate features, eg. if we want to upgrade a guest driver without rebooting the guest. 2) It gives us a clean way of shutting down virtqueues: after a reset, we know that the buffers won't be used by the host, and 3) It helps the guest recover from messed-up drivers. So we remove the ->shutdown hook, and the only way we now remove feature bits is via reset. We leave it to the driver to do the reset before it deletes queues: the balloon driver, for example, needs to chat to the host in its remove function. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>