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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 09:17:27 +03:00
config VHOST_NET
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>
2013-01-17 06:53:56 +04:00
tristate "Host kernel accelerator for virtio net"
depends on NET && EVENTFD && (TUN || !TUN) && (MACVTAP || !MACVTAP)
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 07:20:14 +04:00
select VHOST_RING
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 09:17:27 +03:00
---help---
This kernel module can be loaded in host kernel to accelerate
guest networking with virtio_net. Not to be confused with virtio_net
module itself which needs to be loaded in guest kernel.
To compile this driver as a module, choose M here: the module will
be called vhost_net.
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 04:52:59 +04:00
config VHOST_SCSI
tristate "VHOST_SCSI TCM fabric driver"
depends on TARGET_CORE && EVENTFD && m
Lots of virtio work which wasn't quite ready for last merge window. Plus I dived into lguest again, reworking the pagetable code so we can move the switcher page: our fixmaps sometimes take more than 2MB now... Cheers, Rusty. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAABAgAGBQJRga7lAAoJENkgDmzRrbjx/yIQAKpqIBtxOJeYH3SY+Uoe7Cfp toNYcpJEldvb0UcWN8M2cSZpHoxl1SUoq9djwcM29tcKa7EZAjHaGtb/Q1qMTDgv +B3WAfiGU2pmXFxLAkbrlLNGnysy24JspqJQ5hcYV84EiBxQdZp+nCYgOphd+GMK ww16vo9ya8jFjzt3GeRp/Heb3vEzV4Cp6BC3i0m8A3WNpEpbRb66pqXNk5o8ggJO SxQOKSXmUM+0m+jKSul5xn3e2Ls2LOrZZ8/DIHA+gW66N4Zab7n2/j1Q9VRxb4lh FqnR7KwgBX8OCh9IsBDqQYS7MohvMYge6eUdLtFrq84jvMleMEhrC8q9v2tucFUb 5t18CLwvyK7Gdg6UCKiZ7YSPcuURAILO16al9bh5IseeBDsuX+43VsvQoBmFn9k6 cLOVTZ6BlOmahK5PyRYFSvLa9Rxzr/05Mr7oYq9UgshD9io78dnqczFYIORF53rW zD7C4HuTZfYJFfNd0wAJ0RfVXnf8QvDlMdo7zPC26DSXNWqj8OexCY0qqSWUB+2F vcfJP6NkV4fZB8aawWIFUVwc64yqtt2uPVLa7ATZWqk16PgKrchGewmw3tiEwOgu 1l7xgffTRRUIJsqaCZoXdgw3yezcKRjuUBcOxL09lDAAhc+NxWNvzZBsKp66DwDk yZQKn0OdXnuf0CeEOfFf =1tYL -----END PGP SIGNATURE----- Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio & lguest updates from Rusty Russell: "Lots of virtio work which wasn't quite ready for last merge window. Plus I dived into lguest again, reworking the pagetable code so we can move the switcher page: our fixmaps sometimes take more than 2MB now..." Ugh. Annoying conflicts with the tcm_vhost -> vhost_scsi rename. Hopefully correctly resolved. * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (57 commits) caif_virtio: Remove bouncing email addresses lguest: improve code readability in lg_cpu_start. virtio-net: fill only rx queues which are being used lguest: map Switcher below fixmap. lguest: cache last cpu we ran on. lguest: map Switcher text whenever we allocate a new pagetable. lguest: don't share Switcher PTE pages between guests. lguest: expost switcher_pages array (as lg_switcher_pages). lguest: extract shadow PTE walking / allocating. lguest: make check_gpte et. al return bool. lguest: assume Switcher text is a single page. lguest: rename switcher_page to switcher_pages. lguest: remove RESERVE_MEM constant. lguest: check vaddr not pgd for Switcher protection. lguest: prepare to make SWITCHER_ADDR a variable. virtio: console: replace EMFILE with EBUSY for already-open port virtio-scsi: reset virtqueue affinity when doing cpu hotplug virtio-scsi: introduce multiqueue support virtio-scsi: push vq lock/unlock into virtscsi_vq_done virtio-scsi: pass struct virtio_scsi to virtqueue completion function ...
2013-05-03 01:14:04 +04:00
select VHOST_RING
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 04:52:59 +04:00
default n
---help---
Say M here to enable the vhost_scsi TCM fabric module
for use with virtio-scsi guests
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 07:20:14 +04:00
config VHOST_RING
tristate
---help---
This option is selected by any driver which needs to access
the host side of a virtio ring.
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