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path: root/drivers/vhost/net.c
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2010-03-17vhost: fix interrupt mitigation with raw socketsMichael S. Tsirkin1-1/+1
A thinko in code means we never trigger interrupt mitigation. Fix this. Reported-by: Juan Quintela <quintela@redhat.com> Reported-by: Unai Uribarri <unai.uribarri@optenet.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2010-03-07vhost: fix error path in vhost_net_set_backendJeff Dike1-3/+5
An error could cause vhost_net_set_backend to exit without unlocking vq->mutex. Fix this. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2010-02-28vhost-net: restart tx poll on sk_sndbuf fullSridhar Samudrala1-1/+5
guest to remote communication with vhost net sometimes stops until guest driver is restarted. This happens when we get guest kick precisely when the backend send queue is full, as a result handle_tx() returns without polling backend. This patch fixes this by restarting tx poll on this condition. Signed-off-by: Sridhar Samudrala <samudrala@us.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Tom Lendacky <toml@us.ibm.com>
2010-02-18net/macvtap: add vhost supportArnd Bergmann1-2/+6
This adds support for passing a macvtap file descriptor into vhost-net, much like we already do for tun/tap. Most of the new code is taken from the respective patch in the tun driver and may get consolidated in the future. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-15vhost_net: a kernel-level virtio serverMichael S. Tsirkin1-0/+661
What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration, bug work-arounds in userspace) - write logging is supported (good for migration) - support memory table and not just an offset (needed for kvm) common virtio related code has been put in a separate file vhost.c and can be made into a separate module if/when more backends appear. I used Rusty's lguest.c as the source for developing this part : this supplied me with witty comments I wouldn't be able to write myself. What it is not: vhost net is not a bus, and not a generic new system call. No assumptions are made on how guest performs hypercalls. Userspace hypervisors are supported as well as kvm. How it works: Basically, we connect virtio frontend (configured by userspace) to a backend. The backend could be a network device, or a tap device. Backend is also configured by userspace, including vlan/mac etc. Status: This works for me, and I haven't see any crashes. Compared to userspace, people reported improved latency (as I save up to 4 system calls per packet), as well as better bandwidth and CPU utilization. Features that I plan to look at in the future: - mergeable buffers - zero copy - scalability tuning: figure out the best threading model to use Note on RCU usage (this is also documented in vhost.h, near private_pointer which is the value protected by this variant of RCU): what is happening is that the rcu_dereference() is being used in a workqueue item. The role of rcu_read_lock() is taken on by the start of execution of the workqueue item, of rcu_read_unlock() by the end of execution of the workqueue item, and of synchronize_rcu() by flush_workqueue()/flush_work(). In the future we might need to apply some gcc attribute or sparse annotation to the function passed to INIT_WORK(). Paul's ack below is for this RCU usage. (Includes fixes by Alan Cox <alan@linux.intel.com>, David L Stevens <dlstevens@us.ibm.com>, Chris Wright <chrisw@redhat.com>) Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>