linux.git/drivers/char/virtio_console.c, branch v5.17

virtio_console: break out of buf poll on remove

2022-03-04T13:33:22+00:00

A common pattern for device reset is currently:
vdev->config->reset(vdev);
.. cleanup ..

reset prevents new interrupts from arriving and waits for interrupt
handlers to finish.

However if - as is common - the handler queues a work request which is
flushed during the cleanup stage, we have code adding buffers / trying
to get buffers while device is reset. Not good.

This was reproduced by running
	modprobe virtio_console
	modprobe -r virtio_console
in a loop.

Fix this up by calling virtio_break_device + flush before reset.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1786239
Signed-off-by: Michael S. Tsirkin

virtio: wrap config->reset calls

2022-01-14T23:50:52+00:00

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

virtio_console: validate max_nr_ports before trying to use it

2021-11-01T09:26:48+00:00

We calculate nr_ports based on the max_nr_ports:

nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;

If the device advertises a large max_nr_ports, we will end up with a
integer overflow. Fixing this by validating the max_nr_ports and fail
the probe for invalid max_nr_ports in this case.

Cc: Amit Shah 
Signed-off-by: Jason Wang 
Link: https://lore.kernel.org/r/20211019070152.8236-3-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin

virtio_console: Assure used length from device is limited

2021-07-03T08:50:53+00:00

The buf->len might come from an untrusted device. This
ensures the value would not exceed the size of the buffer
to avoid data corruption or loss.

Signed-off-by: Xie Yongji 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/r/20210525125622.1203-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin

virtio_console: remove pointless check for debugfs_create_dir()

2021-03-10T08:21:02+00:00

It is impossible for debugfs_create_dir() to return NULL, so checking
for it gives people a false sense that they actually are doing something
if an error occurs.  As there is no need to ever change kernel logic if
debugfs is working "properly" or not, there is no need to check the
return value of debugfs calls, so remove the checks here as they will
never be triggered and are wrong.

Cc: Amit Shah 
Cc: Arnd Bergmann 
Cc: virtualization@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Amit Shah 
Link: https://lore.kernel.org/r/20210216150410.3844635-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

virtio: virtio_console: fix DMA memory allocation for rproc serial

2020-11-09T17:03:33+00:00

Since commit 086d08725d34 ("remoteproc: create vdev subdevice with
specific dma memory pool"), every remoteproc has a DMA subdevice
("remoteprocX#vdevYbuffer") for each virtio device, which inherits
DMA capabilities from the corresponding platform device. This allowed
to associate different DMA pools with each vdev, and required from
virtio drivers to perform DMA operations with the parent device
(vdev->dev.parent) instead of grandparent (vdev->dev.parent->parent).

virtio_rpmsg_bus was already changed in the same merge cycle with
commit d999b622fcfb ("rpmsg: virtio: allocate buffer from parent"),
but virtio_console did not. In fact, operations using the grandparent
worked fine while the grandparent was the platform device, but since
commit c774ad010873 ("remoteproc: Fix and restore the parenting
hierarchy for vdev") this was changed, and now the grandparent device
is the remoteproc device without any DMA capabilities.
So, starting v5.8-rc1 the following warning is observed:

[    2.483925] ------------[ cut here ]------------
[    2.489148] WARNING: CPU: 3 PID: 101 at kernel/dma/mapping.c:427 0x80e7eee8
[    2.489152] Modules linked in: virtio_console(+)
[    2.503737]  virtio_rpmsg_bus rpmsg_core
[    2.508903]
[    2.528898] 
[    2.913043]
[    2.914907] ---[ end trace 93ac8746beab612c ]---
[    2.920102] virtio-ports vport1p0: Error allocating inbufs

kernel/dma/mapping.c:427 is:

WARN_ON_ONCE(!dev->coherent_dma_mask);

obviously because the grandparent now is remoteproc dev without any
DMA caps:

[    3.104943] Parent: remoteproc0#vdev1buffer, grandparent: remoteproc0

Fix this the same way as it was for virtio_rpmsg_bus, using just the
parent device (vdev->dev.parent, "remoteprocX#vdevYbuffer") for DMA
operations.
This also allows now to reserve DMA pools/buffers for rproc serial
via Device Tree.

Fixes: c774ad010873 ("remoteproc: Fix and restore the parenting hierarchy for vdev")
Cc: stable@vger.kernel.org # 5.1+
Reviewed-by: Mathieu Poirier 
Acked-by: Jason Wang 
Signed-off-by: Alexander Lobakin 
Date: Thu, 5 Nov 2020 11:10:24 +0800
Link: https://lore.kernel.org/r/AOKowLclCbOCKxyiJ71WeNyuAAj2q8EUtxrXbyky5E@cp7-web-042.plabs.ch
Signed-off-by: Greg Kroah-Hartman

Merge v5.8-rc6 into char-misc-next

2020-07-20T07:43:40+00:00

We need the char/misc fixes in here as well.

Signed-off-by: Greg Kroah-Hartman

virtio: virtio_console: add missing MODULE_DEVICE_TABLE() for rproc serial

2020-07-10T13:12:48+00:00

rproc_serial_id_table lacks an exposure to module devicetable, so
when remoteproc firmware requests VIRTIO_ID_RPROC_SERIAL, no uevent
is generated and no module autoloading occurs.
Add missing MODULE_DEVICE_TABLE() annotation and move the existing
one for VIRTIO_ID_CONSOLE right to the table itself.

Fixes: 1b6370463e88 ("virtio_console: Add support for remoteproc serial")
Cc:  # v3.8+
Signed-off-by: Alexander Lobakin 
Reviewed-by: Amit Shah 
Link: https://lore.kernel.org/r/x7C_CbeJtoGMy258nwAXASYz3xgFMFpyzmUvOyZzRnQrgWCREBjaqBOpAUS7ol4NnZYvSVwmTsCG0Ohyfvta-ygw6HMHcoeKK0C3QFiAO_Q=@pm.me
Signed-off-by: Greg Kroah-Hartman

virtio_console: Constify some static variables

2020-07-10T12:50:51+00:00

The id_table and feature_table pointers in struct virtio_driver are
pointers to const. Mark the corresponding static variables const to
allow the compiler to put them in read-only memory.

Before:
   text    data     bss     dec     hex filename
  25447     713      76   26236    667c drivers/char/virtio_console.o

After:
   text    data     bss     dec     hex filename
  25488     673      76   26237    667d drivers/char/virtio_console.o

Signed-off-by: Rikard Falkeborn 
Acked-by: Arnd Bergmann 
Reviewed-by: Amit Shah 
Link: https://lore.kernel.org/r/20200701200950.30314-6-rikard.falkeborn@gmail.com
Signed-off-by: Greg Kroah-Hartman

fs: rename pipe_buf ->steal to ->try_steal

2020-05-20T16:14:10+00:00

And replace the arcane return value convention with a simple bool
where true means success and false means failure.

[AV: braino fix folded in]

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro