virtio_bt: call scheduler when we free unused buffs

For virtio-net we were getting CPU stall warnings, and fixed it by
calling the scheduler: see f8bb51043945 ("virtio_net: suppress cpu stall
when free_unused_bufs").

This driver is similar so theoretically the same logic applies.

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
Message-Id: <20230609131817.712867-4-xianting.tian@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio_bt: Fix alignment in configuration struct

The current version of the configuration structure has unaligned
16-bit fields, but according to the specification [1], access to
the configuration space must be aligned.

Add a second, aligned version of the configuration structure
and a new feature bit indicating that this version is being used.

[1] https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.pdf

Signed-off-by: Igor Skalkin <Igor.Skalkin@opensynergy.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: virtio_bt: fix device removal

Device removal is clearly out of virtio spec: it attempts to remove
unused buffers from a VQ before invoking device reset. To fix, make
open/close NOPs and do all cleanup/setup in probe/remove.

NB: This is a hacky way to handle this - virtbt_{open,close} as NOP is
not really what a driver is supposed to be doing. These are transport
enable/disable callbacks from the BT core towards the driver. It maps to
a device being enabled/disabled by something like bluetoothd for
example. So if disabled, users expect that no resources/queues are in
use. It does work with all other transports like USB, SDIO, UART etc.
There should be no buffer used if the device is powered off. We also
don’t have any USB URBs in-flight if the transport is not active.

The way to implement a proper fix would be using vq reset if supported,
or even using a full device reset.

The cost of the hack is a single skb wasted on an unused bt device.

NB2: with this fix in place driver still suffers from a race condition
if an interrupt triggers while device is being reset. To fix, in the
virtbt_close() callback we should deactivate all interrupts. To be
fixed.

squashed fixup: bluetooth: virtio_bt: fix an error code in probe()

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20220811080943.198245-1-mst@redhat.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Igor Skalkin <Igor.Skalkin@opensynergy.com>

Bluetooth: virtio_bt: Use skb_put to set length

By using skb_put we ensure that skb->tail is set
correctly. Currently, skb->tail is always zero, which
leads to errors, such as the following page fault in
rfcomm_recv_frame:

BUG: unable to handle page fault for address: ffffed1021de29ff
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
RIP: 0010:rfcomm_run+0x831/0x4040 (net/bluetooth/rfcomm/core.c:1751)

Fixes: afd2daa26c7a ("Bluetooth: Add support for virtio transport driver")
Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

virtio: wrap config->reset calls

This will enable cleanups down the road.
The idea is to disable cbs, then add "flush_queued_cbs" callback
as a parameter, this way drivers can flush any work
queued after callbacks have been disabled.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Bluetooth: virtio_bt: fix memory leak in virtbt_rx_handle()

On the reception of packets with an invalid packet type, the memory of
the allocated socket buffers is never freed. Add a default case that frees
these to avoid a memory leak.

Fixes: afd2daa26c7a ("Bluetooth: Add support for virtio transport driver")
Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: virtio_bt: add missing null pointer check on alloc_skb call return

The call to alloc_skb with the GFP_KERNEL flag can return a null sk_buff
pointer, so add a null check to avoid any null pointer deference issues.

Addresses-Coverity: ("Dereference null return value")
Fixes: afd2daa26c7a ("Bluetooth: Add support for virtio transport driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: Add support for virtio transport driver

This adds support for Bluetooth HCI transport over virtio.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>