linux.git/drivers/virtio, branch v5.1-rc2

virtio: hint if callbacks surprisingly might sleep

2019-03-06T16:19:57+00:00

A virtio transport is free to implement some of the callbacks in
virtio_config_ops in a matter that they cannot be called from
atomic context (e.g. virtio-ccw, which maps a lot of the callbacks
to channel I/O, which is an inherently asynchronous mechanism).
This can be very surprising for developers using the much more
common virtio-pci transport, just to find out that things break
when used on s390.

The documentation for virtio_config_ops now contains a comment
explaining this, but it makes sense to add a might_sleep() annotation
to various wrapper functions in the virtio core to avoid surprises
later.

Note that annotations are NOT added to two classes of calls:
- direct calls from device drivers (all current callers should be
  fine, however)
- calls which clearly won't be made from atomic context (such as
  those ultimately coming in via the driver core)

Signed-off-by: Cornelia Huck 
Signed-off-by: Michael S. Tsirkin

virtio_balloon: remove the unnecessary 0-initialization

2019-03-06T16:19:33+00:00

We've changed to kzalloc the vb struct, so no need to 0-initialize
this field one more time.

Signed-off-by: Wei Wang 
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Cornelia Huck

virtio-balloon: improve update_balloon_size_func

2019-03-06T16:19:33+00:00

There is no need to update the balloon actual register when there is no
ballooning request. This patch avoids update_balloon_size when diff is 0.

Signed-off-by: Wei Wang 
Reviewed-by: Cornelia Huck 
Reviewed-by: Halil Pasic 
Signed-off-by: Michael S. Tsirkin

virtio: Introduce virtio_max_dma_size()

2019-03-06T16:19:15+00:00

This function returns the maximum segment size for a single
dma transaction of a virtio device. The possible limit comes
from the SWIOTLB implementation in the Linux kernel, that
has an upper limit of (currently) 256kb of contiguous
memory it can map. Other DMA-API implementations might also
have limits.

Use the new dma_max_mapping_size() function to determine the
maximum mapping size when DMA-API is in use for virtio.

Cc: stable@vger.kernel.org
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Joerg Roedel 
Signed-off-by: Michael S. Tsirkin

virtio: drop internal struct from UAPI

2019-02-05T20:29:48+00:00

There's no reason to expose struct vring_packed in UAPI - if we do we
won't be able to change or drop it, and it's not part of any interface.

Let's move it to virtio_ring.c

Cc: Tiwei Bie 
Signed-off-by: Michael S. Tsirkin

virtio: support VIRTIO_F_ORDER_PLATFORM

2019-01-24T15:15:42+00:00

This patch introduces the support for VIRTIO_F_ORDER_PLATFORM.
If this feature is negotiated, the driver must use the barriers
suitable for hardware devices. Otherwise, the device and driver
are assumed to be implemented in software, that is they can be
assumed to run on identical CPUs in an SMP configuration. Thus
a weaker form of memory barriers is sufficient to yield better
performance.

It is recommended that an add-in card based PCI device offers
this feature for portability. The device will fail to operate
further or will operate in a slower emulation mode if this
feature is offered but not accepted.

Signed-off-by: Tiwei Bie 
Signed-off-by: Michael S. Tsirkin

virtio-balloon: tweak config_changed implementation

2019-01-15T01:15:20+00:00

virtio-ccw has deadlock issues with reading the config space inside the
interrupt context, so we tweak the virtballoon_changed implementation
by moving the config read operations into the related workqueue contexts.
The config_read_bitmap is used as a flag to the workqueue callbacks
about the related config fields that need to be read.

The cmd_id_received is also renamed to cmd_id_received_cache, and
the value should be obtained via virtio_balloon_cmd_id_received.

Reported-by: Christian Borntraeger 
Signed-off-by: Wei Wang 
Reviewed-by: Cornelia Huck 
Reviewed-by: Halil Pasic 
Signed-off-by: Michael S. Tsirkin 
Cc: stable@vger.kernel.org
Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
Tested-by: Christian Borntraeger

virtio: don't allocate vqs when names[i] = NULL

2019-01-15T01:15:19+00:00

Some vqs may not need to be allocated when their related feature bits
are disabled. So callers may pass in such vqs with "names = NULL".
Then we skip such vq allocations.

Signed-off-by: Wei Wang 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Wei Wang 
Signed-off-by: Wei Wang 
Reviewed-by: Cornelia Huck 
Cc: stable@vger.kernel.org
Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")

virtio_pci: use queue idx instead of array idx to set up the vq

2019-01-15T01:15:18+00:00

When find_vqs, there will be no vq[i] allocation if its corresponding
names[i] is NULL. For example, the caller may pass in names[i] (i=4)
with names[2] being NULL because the related feature bit is turned off,
so technically there are 3 queues on the device, and name[4] should
correspond to the 3rd queue on the device.

So we use queue_idx as the queue index, which is increased only when the
queue exists.

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

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2019-01-03T02:54:45+00:00

Pull virtio/vhost updates from Michael Tsirkin:
"Features, fixes, cleanups:

   - discard in virtio blk

   - misc fixes and cleanups"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: correct the related warning message
  vhost: split structs into a separate header file
  virtio: remove deprecated VIRTIO_PCI_CONFIG()
  vhost/vsock: switch to a mutex for vhost_vsock_hash
  virtio_blk: add discard and write zeroes support