linux-toradex.git/drivers/vhost/vhost.c, branch v4.6-rc5

vhost_net: basic polling support

2016-03-11T00:18:53+00:00

This patch tries to poll for new added tx buffer or socket receive
queue for a while at the end of tx/rx processing. The maximum time
spent on polling were specified through a new kind of vring ioctl.

Signed-off-by: Jason Wang 
Signed-off-by: Michael S. Tsirkin

vhost: introduce vhost_vq_avail_empty()

2016-03-11T00:18:50+00:00

This patch introduces a helper which will return true if we're sure
that the available ring is empty for a specific vq. When we're not
sure, e.g vq access failure, return false instead. This could be used
for busy polling code to exit the busy loop.

Signed-off-by: Jason Wang 
Signed-off-by: Michael S. Tsirkin

vhost: introduce vhost_has_work()

2016-03-11T00:18:45+00:00

This path introduces a helper which can give a hint for whether or not
there's a work queued in the work list. This could be used for busy
polling code to exit the busy loop.

Signed-off-by: Jason Wang 
Signed-off-by: Michael S. Tsirkin

vhost: rename vhost_init_used()

2016-03-02T15:02:04+00:00

Looking at how callers use this, maybe we should just rename init_used
to vhost_vq_init_access. The _used suffix was a hint that we
access the vq used ring. But maybe what callers care about is
that it must be called after access_ok.

Also, this function manipulates the vq->is_le field which isn't related
to the vq used ring.

This patch simply renames vhost_init_used() to vhost_vq_init_access() as
suggested by Michael.

No behaviour change.

Signed-off-by: Greg Kurz 
Signed-off-by: Michael S. Tsirkin

vhost: rename cross-endian helpers

2016-03-02T15:02:00+00:00

The default use case for vhost is when the host and the vring have the
same endianness (default native endianness). But there are cases where
they differ and vhost should byteswap when accessing the vring.

The first case is when the host is big endian and the vring belongs to
a virtio 1.0 device, which is always little endian.

This is covered by the vq->is_le field. This field is initialized when
userspace calls the VHOST_SET_FEATURES ioctl. It is reset when the device
stops.

We already have a vhost_init_is_le() helper, but the reset operation is
opencoded as follows:

	vq->is_le = virtio_legacy_is_little_endian();

It isn't clear that we are resetting vq->is_le here.

This patch moves the code to a helper with a more explicit name.

The other case where we may have to byteswap is when the architecture can
switch endianness at runtime (bi-endian). If endianness differs in the host
and in the guest, then legacy devices need to be used in cross-endian mode.

This mode is available with CONFIG_VHOST_CROSS_ENDIAN_LEGACY=y, which
introduces a vq->user_be field. Userspace may enable cross-endian mode
by calling the SET_VRING_ENDIAN ioctl before the device is started. The
cross-endian mode is disabled when the device is stopped.

The current names of the helpers that manipulate vq->user_be are unclear.

This patch renames those helpers to clearly show that this is cross-endian
stuff and with explicit enable/disable semantics.

No behaviour change.

Signed-off-by: Greg Kurz 
Signed-off-by: Michael S. Tsirkin

vhost: fix error path in vhost_init_used()

2016-03-02T15:01:49+00:00

We don't want side effects. If something fails, we rollback vq->is_le to
its previous value.

Signed-off-by: Greg Kurz 
Signed-off-by: Michael S. Tsirkin

vhost: replace % with & on data path

2015-12-07T15:28:10+00:00

We know vring num is a power of 2, so use &
to mask the high bits.

Signed-off-by: Michael S. Tsirkin

vhost: relax log address alignment

2015-12-07T15:27:54+00:00

commit 5d9a07b0de512b77bf28d2401e5fe3351f00a240 ("vhost: relax used
address alignment") fixed the alignment for the used virtual address,
but not for the physical address used for logging.

That's a mistake: alignment should clearly be the same for virtual and
physical addresses,

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin

vhost: fix error handling for memory region alloc

2015-07-27T15:05:05+00:00

callers of vhost_kvzalloc() expect the same behaviour on
allocation error as from kmalloc/vmalloc i.e. NULL return
value. So just return vzmalloc() returned value instead of
returning ERR_PTR(-ENOMEM)

Fixes: 4de7255f7d2be5 ("vhost: extend memory regions allocation to vmalloc")

Spotted-by: Dan Carpenter 
Suggested-by: Julia Lawall 
Signed-off-by: Igor Mammedov 
Signed-off-by: Michael S. Tsirkin

vhost: actually track log eventfd file

2015-07-27T15:04:58+00:00

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