linux-stable.git/drivers/vhost/vhost.h, branch linux-4.6.y

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: fix performance on LE hosts

2015-10-28T03:17:03+00:00

commit 2751c9882b947292fcfb084c4f604e01724af804 ("vhost: cross-endian
support for legacy devices") introduced a minor regression: even with
cross-endian disabled, and even on LE host, vhost_is_little_endian is
checking is_le flag so there's always a branch.

To fix, simply check virtio_legacy_is_little_endian first.

Cc: Greg Kurz 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Greg Kurz 
Signed-off-by: David S. Miller

vhost: move features to core

2015-09-16T09:48:07+00:00

virtio 1 and any layout are core features, move them
there. This fixes vhost test.

Signed-off-by: Michael S. Tsirkin

vhost: cross-endian support for legacy devices

2015-06-01T13:48:55+00:00

This patch brings cross-endian support to vhost when used to implement
legacy virtio devices. Since it is a relatively rare situation, the
feature availability is controlled by a kernel config option (not set
by default).

The vq->is_le boolean field is added to cache the endianness to be
used for ring accesses. It defaults to native endian, as expected
by legacy virtio devices. When the ring gets active, we force little
endian if the device is modern. When the ring is deactivated, we
revert to the native endian default.

If cross-endian was compiled in, a vq->user_be boolean field is added
so that userspace may request a specific endianness. This field is
used to override the default when activating the ring of a legacy
device. It has no effect on modern devices.

Signed-off-by: Greg Kurz 

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck 
Reviewed-by: David Gibson

virtio: add explicit big-endian support to memory accessors

2015-06-01T13:48:54+00:00

The current memory accessors logic is:
- little endian if little_endian
- native endian (i.e. no byteswap) if !little_endian

If we want to fully support cross-endian vhost, we also need to be
able to convert to big endian.

Instead of changing the little_endian argument to some 3-value enum, this
patch changes the logic to:
- little endian if little_endian
- big endian if !little_endian

The native endian case is handled by all users with a trivial helper. This
patch doesn't change any functionality, nor it does add overhead.

Signed-off-by: Greg Kurz 

Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck 
Reviewed-by: David Gibson

vhost: introduce vhost_is_little_endian() helper

2015-06-01T13:48:53+00:00

Signed-off-by: Greg Kurz 

Signed-off-by: Michael S. Tsirkin 
Acked-by: Cornelia Huck 
Reviewed-by: David Gibson

vhost: remove unnecessary forward declarations in vhost.h

2014-12-09T10:06:33+00:00

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