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linux/drivers/vhost/Kconfig

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vhost_net: a kernel-level virtio server 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>
2010-01-14 06:17:27 +00:00
drivers/vhost: remove depends on CONFIG_EXPERIMENTAL The CONFIG_EXPERIMENTAL config item has not carried much meaning for a while now and is almost always enabled by default. As agreed during the Linux kernel summit, remove it from any "depends on" lines in Kconfigs. Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-16 18:53:56 -08:00
tap: tap as an independent module This patch makes tap a separate module for other types of virtual interfaces, for example, ipvlan to use. Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-10 16:03:51 -08:00
vhost: Make vhost a separate module Currently, vhost-net and vhost-scsi are sharing the vhost core code. However, vhost-scsi shares the code by including the vhost.c file directly. Making vhost a separate module makes it is easier to share code with other vhost devices. Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-05-06 16:38:21 +08:00
vhost_net: a kernel-level virtio server 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>
2010-01-14 06:17:27 +00:00
vhost_scsi: module rename Rename module and update Kconfig and Makefile. Add alias for compatibility with old userspace scripts if any. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Asias He <asias@redhat.com> Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-05-02 03:52:59 +03:00
vhost: Make vhost a separate module Currently, vhost-net and vhost-scsi are sharing the vhost core code. However, vhost-scsi shares the code by including the vhost.c file directly. Making vhost a separate module makes it is easier to share code with other vhost devices. Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-05-06 16:38:21 +08:00
vhost_scsi: module rename Rename module and update Kconfig and Makefile. Add alias for compatibility with old userspace scripts if any. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Asias He <asias@redhat.com> Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
2013-05-02 03:52:59 +03:00
vringh: host-side implementation of virtio rings. Getting use of virtio rings correct is tricky, and a recent patch saw an implementation of in-kernel rings (as separate from userspace). This abstracts the business of dealing with the virtio ring layout from the access (userspace or direct); to do this, we use function pointers, which gcc inlines correctly. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Michael S. Tsirkin <mst@redhat.com>
2013-03-20 13:50:14 +10:30
VSOCK: Add Makefile and Kconfig Enable virtio-vsock and vhost-vsock. Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-07-28 15:36:35 +01:00
vhost: Make vhost a separate module Currently, vhost-net and vhost-scsi are sharing the vhost core code. However, vhost-scsi shares the code by including the vhost.c file directly. Making vhost a separate module makes it is easier to share code with other vhost devices. Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-05-06 16:38:21 +08:00
vhost: cross-endian support for legacy devices This patch brings cross-endian support to vhost when used to implement legacy virtio devices. Since it is a relatively rare situation, the feature availability is controlled by a kernel config option (not set by default). The vq->is_le boolean field is added to cache the endianness to be used for ring accesses. It defaults to native endian, as expected by legacy virtio devices. When the ring gets active, we force little endian if the device is modern. When the ring is deactivated, we revert to the native endian default. If cross-endian was compiled in, a vq->user_be boolean field is added so that userspace may request a specific endianness. This field is used to override the default when activating the ring of a legacy device. It has no effect on modern devices. Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2015-04-24 14:27:24 +02:00