| 47283bef7ed356629467d1fac61687756e48f254 |
|
05-Jun-2014 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: move memory pointer to VQs
commit 2ae76693b8bcabf370b981cd00c36cd41d33fabc
vhost: replace rcu with mutex
replaced rcu sync for memory accesses with VQ mutex locl/unlock.
This is correct since all accesses are under VQ mutex, but incomplete:
we still do useless rcu lock/unlock operations, someone might copy this
code into some other context where this won't be right.
This use of RCU is also non standard and hard to understand.
Let's copy the pointer to each VQ structure, this way
the access rules become straight-forward, and there's
no need for RCU anymore.
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| ea16c51433510f7f758382dec5b933fc0797f244 |
|
05-Jun-2014 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: move acked_features to VQs
Refactor code to make sure features are only accessed
under VQ mutex. This makes everything simpler, no need
for RCU here anymore.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 59566b6e8cc8f8a05022e0f01a1b90974003f092 |
|
06-Dec-2013 |
Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> |
vhost: remove the dead branch
Since vhost_dev_init() forever return 0, some branches are never run,
therefore need to be removed.
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| 22fa90c7fb479694d6affebc049d21f06b714be6 |
|
07-May-2013 |
Asias He <asias@redhat.com> |
vhost: Remove custom vhost rcu usage
Now, vq->private_data is always accessed under vq mutex. No need to play
the vhost rcu trick.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 6ac1afbf6132df0fcb0898f3509371305af7de16 |
|
06-May-2013 |
Asias He <asias@redhat.com> |
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>
|
| 05c05351943cc03bf5c77e86953b24ae6fb21368 |
|
06-Jun-2013 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: check owner before we overwrite ubuf_info
If device has an owner, we shouldn't touch ubuf_info
since it might be in use.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| e40ab7484f8e9cc9f5e59ae53214800e50f5615e |
|
06-May-2013 |
Asias He <asias@redhat.com> |
vhost: Remove vhost_enable_zcopy in vhost.h
It is net.c specific.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| ab00c42a567b21024383db3fac98118497d6270b |
|
06-May-2013 |
Asias He <asias@redhat.com> |
vhost: Remove comments for hdr in vhost.h
It is supposed to be removed when hdr is moved into vhost_net_virtqueue.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 8570a6e72c5bfb1aee8225b8c4814cdc28417a20 |
|
06-May-2013 |
Asias He <asias@redhat.com> |
vhost: Move VHOST_NET_FEATURES to net.c
vhost.h should not depend on device specific marcos like
VHOST_NET_F_VIRTIO_NET_HDR and VIRTIO_NET_F_MRG_RXBUF.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 54db63c2ca153ebf0c868cdf79f52ec9e701d38c |
|
06-May-2013 |
Asias He <asias@redhat.com> |
vhost: Export vhost_dev_set_owner
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 150b9e51ae975ca1fe468c565870fbc4a96e0574 |
|
28-Apr-2013 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: fix error handling in RESET_OWNER ioctl
RESET_OWNER ioctl would leave the fd in a bad state if
memory allocation failed: device is stopped
but owner is not reset. Make state changes
after allocating memory, such that a failed
ioctl has no effect.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 81f95a55802be669b3191b2828c34006d0f04214 |
|
28-Apr-2013 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: move per-vq net specific fields out to net
This will remove the need for vhost scsi to pull
in virtio-net.h.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 2839400f8fe28ce216eeeba3fb97bdf90977f7ad |
|
27-Apr-2013 |
Asias He <asias@redhat.com> |
vhost: move vhost-net zerocopy fields to net.c
On top of 'vhost: Allow device specific fields per vq', we can move device
specific fields to device virt queue from vhost virt queue.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 3ab2e420ec1caf4ead233f3161ac7d86fe5d2a9f |
|
27-Apr-2013 |
Asias He <asias@redhat.com> |
vhost: Allow device specific fields per vq
This is useful for any device who wants device specific fields per vq.
For example, tcm_vhost wants a per vq field to track requests which are
in flight on the vq. Also, on top of this we can add patches to move
things like ubufs from vhost.h out to net.c.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 2b8b328b61c799957a456a5a8dab8cc7dea68575 |
|
28-Jan-2013 |
Jason Wang <jasowang@redhat.com> |
vhost_net: handle polling errors when setting backend
Currently, the polling errors were ignored, which can lead following issues:
- vhost remove itself unconditionally from waitqueue when stopping the poll,
this may crash the kernel since the previous attempt of starting may fail to
add itself to the waitqueue
- userspace may think the backend were successfully set even when the polling
failed.
Solve this by:
- check poll->wqh before trying to remove from waitqueue
- report polling errors in vhost_poll_start(), tx_poll_start(), the return value
will be checked and returned when userspace want to set the backend
After this fix, there still could be a polling failure after backend is set, it
will addressed by the next patch.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| 935cdee7ee159569b0aaa10bd9244660f6672b08 |
|
06-Dec-2012 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: avoid backend flush on vring ops
vring changes already do a flush internally where appropriate, so we do
not need a second flush.
It's currently not very expensive but a follow-up patch makes flush more
heavy-weight, so remove the extra flush here to avoid regressing
performance if call or kick fds are changed on data path.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| b211616d712551874db3ce0fb44196f6faad2c34 |
|
01-Nov-2012 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: move -net specific code out
Zerocopy handling code is vhost-net specific.
Move it from vhost.c/vhost.h out to net.c
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| c4fcb586c337f8b8de3a3d7ba8514eed03695f6e |
|
01-Nov-2012 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: track zero copy failures using DMA length
This will be used to disable zerocopy when error rate
is high.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| 70e4cb9aafb3caa9e5eb25614a5bc40b0ffa9ffd |
|
01-Nov-2012 |
Michael S. Tsirkin <mst@redhat.com> |
vhost-net: cleanup macros for DMA status tracking
Better document macros for DMA tracking. Add an
explicit one for DMA in progress instead of
relying on user supplying len != 1.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| e19d6763cc300fcb706bd291b24ac06be71e1ce6 |
|
01-Nov-2012 |
Michael S. Tsirkin <mst@redhat.com> |
skb: report completion status for zero copy skbs
Even if skb is marked for zero copy, net core might still decide
to copy it later which is somewhat slower than a copy in user context:
besides copying the data we need to pin/unpin the pages.
Add a parameter reporting such cases through zero copy callback:
if this happens a lot, device can take this into account
and switch to copying in user context.
This patch updates all users but ignores the passed value for now:
it will be used by follow-up patches.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| 163049aefdc04323a2d17ec9f2862027b43b0502 |
|
21-Jul-2012 |
Stefan Hajnoczi <stefanha@gmail.com> |
vhost: make vhost work queue visible
The vhost work queue allows processing to be done in vhost worker thread
context, which uses the owner process mm. Access to the vring and guest
memory is typically only possible from vhost worker context so it is
useful to allow work to be queued directly by users.
Currently vhost_net only uses the poll wrappers which do not expose the
work queue functions. However, for tcm_vhost (vhost_scsi) it will be
necessary to queue custom work.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Zhi Yong Wu <wuzhy@cn.ibm.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 0dd05a3b60ddf0e216fbd9e5116a5273966fd9db |
|
21-Jul-2012 |
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> |
vhost: Separate vhost-net features from vhost features
In order for other vhost devices to use the VHOST_FEATURES bits the
vhost-net specific bits need to be moved to their own VHOST_NET_FEATURES
constant.
(Asias: Update drivers/vhost/test.c to use VHOST_NET_FEATURES)
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Zhi Yong Wu <wuzhy@cn.ibm.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Asias He <asias@redhat.com>
Signed-off-by: Nicholas A. Bellinger <nab@risingtidesystems.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| ca8f4fb21d08747013cce9cf1840aa5bfc31f2d8 |
|
09-Apr-2012 |
Michael S. Tsirkin <mst@redhat.com> |
skbuff: struct ubuf_info callback type safety
The skb struct ubuf_info callback gets passed struct ubuf_info
itself, not the arg value as the field name and the function signature
seem to imply. Rename the arg field to ctx to match usage,
add documentation and change the callback argument type
to make usage clear and to have compiler check correctness.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| ea5d404655ba3b356d0c06d6a3c4f24112124522 |
|
27-Nov-2011 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: fix release path lockdep checks
We shouldn't hold any locks on release path. Pass a flag to
vhost_dev_cleanup to use the lockdep info correctly.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
|
| 60063497a95e716c9a689af3be2687d261f115b4 |
|
27-Jul-2011 |
Arun Sharma <asharma@fb.com> |
atomic: use <linux/atomic.h>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
| f59281dafb832b161133743fcf3dc29051e6fdb8 |
|
21-Jun-2011 |
Jason Wang <jasowang@redhat.com> |
vhost: init used ring after backend was set
Move the used ring initialization after backend was set. This
makes it possible to disable the backend and tweak the used ring,
then restart. This will also make it possible to log the used ring
write correctly.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| bab632d69ee48a106e779b60cc01adfe80a72807 |
|
18-Jul-2011 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: vhost TX zero-copy support
>From: Shirley Ma <mashirle@us.ibm.com>
This adds experimental zero copy support in vhost-net,
disabled by default. To enable, set
experimental_zcopytx module option to 1.
This patch maintains the outstanding userspace buffers in the
sequence it is delivered to vhost. The outstanding userspace buffers
will be marked as done once the lower device buffers DMA has finished.
This is monitored through last reference of kfree_skb callback. Two
buffer indices are used for this purpose.
The vhost-net device passes the userspace buffers info to lower device
skb through message control. DMA done status check and guest
notification are handled by handle_tx: in the worst case is all buffers
in the vq are in pending/done status, so we need to notify guest to
release DMA done buffers first before we get any new buffers from the
vq.
One known problem is that if the guest stops submitting
buffers, buffers might never get used until some
further action, e.g. device reset. This does not
seem to affect linux guests.
Signed-off-by: Shirley <xma@us.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
| 8ea8cf89e19aeb596b818ee5f2bec8a8b0586b60 |
|
20-May-2011 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: support event index
Support the new event index feature. When acked,
utilize it to reduce the # of interrupts sent to the guest.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
|
| 5e18247b02d60a1ea4bf98c05e139461ca9aec64 |
|
18-Jan-2011 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: rcu annotation fixup
When built with rcu checks enabled, vhost triggers
bogus warnings as vhost features are read without
dev->mutex sometimes, and private pointer is read
with our kind of rcu where work serves as a
read side critical section.
Fixing it properly is not trivial.
Disable the warnings by stubbing out the checks for now.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| a290aec88a9c4747353ea7aa9b2569bd61297c3c |
|
29-Nov-2010 |
Jason Wang <jasowang@redhat.com> |
vhost: fix typos in comment
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| e0e9b406470b8dd75a115cf82c4791f41615c4c3 |
|
14-Sep-2010 |
Jason Wang <jasowang@redhat.com> |
vhost: max s/g to match qemu
Qemu supports up to UIO_MAXIOV s/g so we have to match that because guest
drivers may rely on this.
Allocate indirect and log arrays dynamically to avoid using too much contigious
memory and make the length of hdr array to match the header length since each
iovec entry has a least one byte.
Test with copying large files w/ and w/o migration in both linux and windows
guests.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 28457ee69c473a903e51e26c7bcd6f1e9eceb93e |
|
09-Mar-2010 |
Arnd Bergmann <arnd@relay.de.ibm.com> |
vhost: add __rcu annotations
Also add rcu_dereference_protected() for code paths where locks are held.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
|
| 8dd014adfea6f173c1ef6378f7e5e7924866c923 |
|
27-Jul-2010 |
David Stevens <dlstevens@us.ibm.com> |
vhost-net: mergeable buffers support
This adds support for mergeable buffers in vhost-net: this is needed
for older guests without indirect buffer support, as well
as for zero copy with some devices.
Includes changes by Michael S. Tsirkin to make the
patch as low risk as possible (i.e., close to no changes
when feature is disabled).
Signed-off-by: David Stevens <dlstevens@us.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| c23f3445e68e1db0e74099f264bc5ff5d55ebdeb |
|
02-Jun-2010 |
Tejun Heo <tj@kernel.org> |
vhost: replace vhost_workqueue with per-vhost kthread
Replace vhost_workqueue with per-vhost kthread. Other than callback
argument change from struct work_struct * to struct vhost_work *,
there's no visible change to vhost_poll_*() interface.
This conversion is to make each vhost use a dedicated kthread so that
resource control via cgroup can be applied.
Partially based on Sridhar Samudrala's patch.
* Updated to use sub structure vhost_work instead of directly using
vhost_poll at Michael's suggestion.
* Added flusher wake_up() optimization at Michael's suggestion.
Changes by MST:
* Converted atomics/barrier use to a spinlock.
* Create thread on SET_OWNER
* Fix flushing
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Sridhar Samudrala <samudrala.sridhar@gmail.com>
|
| d5675bd204efd87a174eeea592de23c4c4e7f908 |
|
24-Jun-2010 |
Michael S. Tsirkin <mst@redhat.com> |
vhost: break out of polling loop on error
When ring parsing fails, we currently handle this
as ring empty condition. This means that we enable
kicks and recheck ring empty: if this not empty,
we re-start polling which of course will fail again.
Instead, let's return a negative error code and stop polling.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
|
| 3a4d5c94e959359ece6d6b55045c3f046677f55c |
|
14-Jan-2010 |
Michael S. Tsirkin <mst@redhat.com> |
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>
|