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* headers_check fix: linux/virtio_net.hJaswinder Singh Rajput2009-01-311-0/+1
| | | | | | | | fix the following 'make headers_check' warning: usr/include/linux/virtio_net.h:28: found __[us]{8,16,32,64} type without #include <linux/types.h> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
* virtio_net: VIRTIO_NET_F_MSG_RXBUF (imprive rcv buffer allocation)Mark McLoughlin2008-11-161-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* virtio: clarify that ABI is usable by any implementationsRusty Russell2008-07-251-0/+2
| | | | | | | | | | | | | We want others to implement and use virtio, so it makes sense to BSD license the non-__KERNEL__ parts of the headers to make this crystal clear. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Mark McLoughlin <markmc@redhat.com> Acked-by: Ryan Harper <ryanh@us.ibm.com> Acked-by: Eric Van Hensbergen <ericvh@gmail.com> Acked-by: Anthony Liguori <aliguori@us.ibm.com>
* virtio: Fix typo in virtio_net_hdr commentsMark McLoughlin2008-06-101-1/+1
| | | | | | 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>
* virtio: finer-grained features for virtio_netRusty Russell2008-05-021-2/+11
| | | | | | | | | | | | | 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>
* virtio: Tweak virtio_net definesRusty Russell2008-02-041-8/+4
| | | | | | | | | | | | | | | | 1) Turn GSO on virtio net into an all-or-nothing (keep checksumming separate). Having multiple bits is a pain: if you can't support something you should handle it in software, which is still a performance win. 2) Make VIRTIO_NET_HDR_GSO_ECN a flag in the header, so it can apply to IPv6 or v4. 3) Rename VIRTIO_NET_F_NO_CSUM to VIRTIO_NET_F_CSUM (ie. means we do checksumming). 4) Add csum and gso params to virtio_net to allow more testing. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: Net header needs hdr_lenRusty Russell2008-02-041-5/+6
| | | | | | | | | It's far easier to deal with packets if we don't have to parse the packet to figure out the header length to know how much to pull into the skb data. Add the field to the virtio_net_hdr struct (and fix the spaces that somehow crept in there). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: simplify config mechanism.Rusty Russell2008-02-041-4/+7
| | | | | | | | | | | | | Previously we used a type/len pair within the config space, but this seems overkill. We now simply define a structure which represents the layout in the config space: the config space can now only be extended at the end. The main driver-visible changes: 1) We indicate what fields are present with an explicit feature bit. 2) Virtqueues are explicitly numbered, and not in the config space. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Net driver using virtioRusty Russell2007-10-231-0/+36
The network driver uses two virtqueues: one for input packets and one for output packets. This has nice locking properties (ie. we don't do any for recv vs send). TODO: 1) Big packets. 2) Multi-client devices (maybe separate driver?). 3) Resolve freeing of old xmit skbs (Christian Borntraeger) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: netdev@vger.kernel.org
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