vhost_net_ubuf_put_and_wait has a confusing name:
it will actually also free it's argument.
Thus since commit 1280c27f
    "vhost-net: flush outstanding DMAs on memory change"
vhost_net_flush tries to use the argument after passing it
to vhost_net_ubuf_put_and_wait, this results
in use after free.
To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
add an new API for callers that want to free ubufs.
Acked-by: NAsias He <asias@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

vhost_net_clear_ubuf_info didn't clear ubuf_info
after kfree, this could trigger double free.
Fix this and simplify this code to make it more robust: make sure
ubuf info is always freed through vhost_net_clear_ubuf_info.
Reported-by: NTommi Rantala <tt.rantala@gmail.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If device has an owner, we shouldn't touch ubuf_info
since it might be in use.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we decide not use zero-copy, msg.control should be set to NULL otherwise
macvtap/tap may set zerocopy callbacks which may decrease the kref of ubufs
wrongly.

Bug were introduced by commit cedb9bdc
(vhost-net: skip head management if no outstanding).

This solves the following warnings:

WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]()
Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge stp llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun]
CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566
Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011
ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48
ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0
ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58
Call Trace:
[<ffffffff81796b73>] dump_stack+0x19/0x1e
[<ffffffff8103d66b>] warn_slowpath_common+0x6b/0xa0
[<ffffffff8103d6b5>] warn_slowpath_null+0x15/0x20
[<ffffffffa0197627>] handle_tx+0x477/0x4b0 [vhost_net]
[<ffffffffa0197690>] handle_tx_kick+0x10/0x20 [vhost_net]
[<ffffffffa019541e>] vhost_worker+0xfe/0x1a0 [vhost_net]
[<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net]
[<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net]
[<ffffffff81061f46>] kthread+0xc6/0xd0
[<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff817a1aec>] ret_from_fork+0x7c/0xb0
[<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
Signed-off-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

[  624.286653] vringh: module license 'unspecified' taints kernel.
Signed-off-by: NDave Jones <davej@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

It was disabled as a workaround. Now userspace bits work fine with it.
The broken version was not ever committed to QEMU, I guess the same is
true for nlkt.

So, let's enable it.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

There's no net specific code in vhost.c anymore,
don't include the virtio_net.h header.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

- Rename vhost_ubuf to vhost_net_ubuf
- Rename vhost_zcopy_mask to vhost_net_zcopy_mask
- Make funcs static
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

It is net.c specific.
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

It is supposed to be removed when hdr is moved into vhost_net_virtqueue.
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

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: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Rename module and update Kconfig and Makefile.
Add alias for compatibility with old userspace
scripts if any.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NAsias He <asias@redhat.com>
Acked-by: NNicholas Bellinger <nab@linux-iscsi.org>

move uapi parts to vhost.h
move .c private parts to .c itself
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NAsias He <asias@redhat.com>
Acked-by: NNicholas Bellinger <nab@linux-iscsi.org>

Move tcm_vhost.c -> scsi.c
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NAsias He <asias@redhat.com>
Acked-by: NNicholas Bellinger <nab@linux-iscsi.org>

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: NMichael S. Tsirkin <mst@redhat.com>

vhost.h only has generic bits now, so we can drop it
virtio-net.h in tcm_vhost.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

This will remove the need for vhost scsi to pull
in virtio-net.h.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add more comments so we remember not to break it
next time we change things.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

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: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Unlike tcm_vhost_evt requests, tcm_vhost_cmd requests are passed to the
target core system, we can not make sure all the pending requests will
be finished by flushing the virt queue.

In this patch, we do refcount for every tcm_vhost_cmd requests to make
vhost_scsi_flush() wait for all the pending requests issued before the
flush operation to be finished.

This is useful when we call vhost_scsi_clear_endpoint() to stop
tcm_vhost. No new requests will be passed to target core system because
we clear the endpoint by setting vs_tpg to NULL. And we wait for all the
old requests. These guarantee no requests will be leaked and existing
requests will be completed.
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

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: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Everything for hotplug is ready. Let's enable the feature bit.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

In commit 365a7150 ([SCSI] virtio-scsi: hotplug support for
virtio-scsi), hotplug support is added to virtio-scsi.

This patch adds hotplug and hotunplug support to tcm_vhost.

You can create or delete a LUN in targetcli to hotplug or hotunplug a
LUN in guest.
Signed-off-by: NAsias He <asias@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We want to use tcm_vhost_mutex to make sure hotplug/hotunplug will not
happen when set_endpoint/clear_endpoint is in process.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

After commit 2b8b328b (vhost_net: handle polling
errors when setting backend), we in fact track the polling state through
poll->wqh, so there's no need to duplicate the work with an extra
vhost_net_polling_state. So this patch removes this and make the code simpler.

This patch also removes the all tx starting/stopping code in tx path according
to Michael's suggestion.

Netperf test shows almost the same result in stream test, but gets improvements
on TCP_RR tests (both zerocopy or copy) especially on low load cases.

Tested between multiqueue kvm guest and external host with two direct
connected 82599s.

zerocopy disabled:

sessions|transaction rates|normalize|
before/after/+improvements
1 | 9510.24/11727.29/+23.3%    | 693.54/887.68/+28.0%   |
25| 192931.50/241729.87/+25.3% | 2376.80/2771.70/+16.6% |
50| 277634.64/291905.76/+5%    | 3118.36/3230.11/+3.6%  |

zerocopy enabled:

sessions|transaction rates|normalize|
before/after/+improvements
1 | 7318.33/11929.76/+63.0%    | 521.86/843.30/+61.6%   |
25| 167264.88/242422.15/+44.9% | 2181.60/2788.16/+27.8% |
50| 272181.02/294347.04/+8.1%  | 3071.56/3257.85/+6.1%  |
Signed-off-by: NJason Wang <jasowang@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Send bad target to guest in case:
1) we can not allocate the cmd
2) fail to submit the cmd
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Share the send bad target code with other use cases.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If we fail to submit the allocated tv_vmd to tcm_vhost_submission_work,
we will leak the tv_vmd. Free tv_vmd on fail path.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We did the length of response check twice.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes guest hang when booting seabios and guest.

  [    0.576238] scsi0 : Virtio SCSI HBA
  [    0.616754] virtio_scsi virtio1: request:id 0 is not a head!

vq->last_used_idx is initialized only when /dev/vhost-scsi is
opened or closed.

   vhost_scsi_open -> vhost_dev_init() -> vhost_vq_reset()
   vhost_scsi_release() -> vhost_dev_cleanup -> vhost_vq_reset()

So, when guest talks to tcm_vhost after seabios does, vq->last_used_idx
still contains the old valule for seabios. This confuses guest.

Fix this by calling vhost_init_used() to init vq->last_used_idx when
we set endpoint.
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Currently, vs->vs_endpoint is used indicate if the endpoint is setup or
not. It is set or cleared in vhost_scsi_set_endpoint() or
vhost_scsi_clear_endpoint() under the vs->dev.mutex lock. However, when
we check it in vhost_scsi_handle_vq(), we ignored the lock.

Instead of using the vs->vs_endpoint and the vs->dev.mutex lock to
indicate the status of the endpoint, we use per virtqueue
vq->private_data to indicate it. In this way, we can only take the
vq->mutex lock which is per queue and make the concurrent multiqueue
process having less lock contention. Further, in the read side of
vq->private_data, we can even do not take the lock if it is accessed in
the vhost worker thread, because it is protected by "vhost rcu".

(nab: Do s/VHOST_FEATURES/~VHOST_SCSI_FEATURES)
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

In vhost_scsi_handle_vq:

      tv_tpg = vs->vs_tpg[target];
      if (!tv_tpg) {
              ....
              return
      }

      tv_cmd = vhost_scsi_allocate_cmd(tv_tpg, &v_req,

1) vs->vs_tpg[target] might change after the NULL check and 2) the above
line might access tv_tpg from vs->vs_tpg[target]. To prevent 2), use
ACCESS_ONCE. Thanks mst for catching this up!
Signed-off-by: NAsias He <asias@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds a VHOST_SCSI_FEATURES mask minus VIRTIO_RING_F_EVENT_IDX
so that vhost-scsi-pci userspace will strip this feature bit once
GET_FEATURES reports it as being unsupported on the host.

This is to avoid a bug where ->handle_kicks() are missed when EVENT_IDX
is enabled by default in userspace code.

(mst: Rename to VHOST_SCSI_FEATURES + add comment)
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NAsias He <asias@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

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: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We also need to flush the vhost_works. It is the completion vhost_work
currently.
Signed-off-by: NAsias He <asias@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

tv_tpg->tv_tpg_vhost_count should be protected by tv_tpg->tv_tpg_mutex.
Signed-off-by: NAsias He <asias@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>