linux-stable.git/drivers/vhost/vhost.c, branch linux-3.18.y

vhost: make sure used idx is seen before log in vhost_add_used_n()

2019-01-13T09:07:10+00:00

[ Upstream commit 841df922417eb82c835e93d4b93eb6a68c99d599 ]

We miss a write barrier that guarantees used idx is updated and seen
before log. This will let userspace sync and copy used ring before
used idx is update. Fix this by adding a barrier before log_write().

Fixes: 8dd014adfea6f ("vhost-net: mergeable buffers support")
Acked-by: Michael S. Tsirkin 
Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

vhost: correctly remove wait queue during poll failure

2018-04-13T17:52:23+00:00

[ Upstream commit dc6455a71c7fc5117977e197f67f71b49f27baba ]

We tried to remove vq poll from wait queue, but do not check whether
or not it was in a list before. This will lead double free. Fixing
this by switching to use vhost_poll_stop() which zeros poll->wqh after
removing poll from waitqueue to make sure it won't be freed twice.

Cc: Darren Kenny 
Reported-by: syzbot+c0272972b01b872e604a@syzkaller.appspotmail.com
Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
Signed-off-by: Jason Wang 
Reviewed-by: Darren Kenny 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

vhost: actually track log eventfd file

2015-08-27T17:25:50+00:00

[ Upstream commit 7932c0bd7740f4cd2aa168d3ce0199e7af7d72d5 ]

While reviewing vhost log code, I found out that log_file is never
set. Note: I haven't tested the change (QEMU doesn't use LOG_FD yet).

Cc: stable@vger.kernel.org
Signed-off-by: Marc-André Lureau 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Sasha Levin

vhost: move memory pointer to VQs

2014-06-09T13:21:07+00:00

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 
Signed-off-by: Michael S. Tsirkin

vhost: move acked_features to VQs

2014-06-09T13:21:06+00:00

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

vhost: replace rcu with mutex

2014-06-09T13:21:06+00:00

All memory accesses are done under some VQ mutex.
So lock/unlock all VQs is a faster equivalent of synchronize_rcu()
for memory access changes.
Some guests cause a lot of these changes, so it's helpful
to make them faster.

Reported-by: "Gonglei (Arei)" 
Signed-off-by: Michael S. Tsirkin

vhost: remove the dead branch

2013-12-06T20:22:05+00:00

Since vhost_dev_init() forever return 0, some branches are never run,
therefore need to be removed.

Signed-off-by: Zhi Yong Wu 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

vhost: wake up worker outside spin_lock

2013-09-17T06:21:32+00:00

the wake_up_process func is included by spin_lock/unlock in
vhost_work_queue,
but it could be done outside the spin_lock.
I have test it with kernel 3.0.27 and guest suse11-sp2 using iperf,
the num as below.
                  original                 modified
thread_num  tp(Gbps)   vhost(%)  |  tp(Gbps)     vhost(%)
1           9.59        28.82    |   9.59        27.49
8           9.61        32.92    |   9.62        26.77
64          9.58        46.48    |   9.55        38.99
256         9.6         63.7     |   9.6         52.59

Signed-off-by: Chuanyu Qin 
Signed-off-by: Michael S. Tsirkin

vhost: switch to use vhost_add_used_n()

2013-09-04T02:46:57+00:00

Let vhost_add_used() to use vhost_add_used_n() to reduce the code
duplication. To avoid the overhead brought by __copy_to_user(). We will use
put_user() when one used need to be added.

Signed-off-by: Jason Wang 
Signed-off-by: David S. Miller

vhost: Include linux/uio.h instead of linux/socket.h

2013-08-20T22:05:04+00:00

memcpy_fromiovec is moved from net/core/iovec.c to lib/iovec.c.
linux/uio.h provides the declaration for memcpy_fromiovec.

Include linux/uio.h instead of inux/socket.h for it.

Signed-off-by: Asias He 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller