[RFC 0/2] virtio-rng: add a control queue

[Laurent Vivier]

The kernel needs sometime to be able to cancel an ongoing command.

For instance, if the virtio-rng device uses the egd backend
and this backend doesn't provide data, the buffer provided by the
kernel is kept as long as it is needed.

On the kernel side, a read blocks until the buffer returns from QEMU.

As the read is done with a mutex held, all the hw_random interface
hangs and we cannot switch to another hw_random backend.

So this series adds a control queue to the virtio-rng device to allow
to flush the virtio-rng input queue to release the kernel mutex and
to allow to switch to another device.

The kernel side series can be found at:

https://github.com/vivier/linux/commits/virtio-rng-ctrl

Laurent Vivier (2):
  virtio-rng: prepare the introduction of a control queue
  virtio-rng: add a control queue

 hw/core/machine.c                           |  1 +
 hw/virtio/trace-events                      |  6 ++
 hw/virtio/virtio-rng.c                      | 99 ++++++++++++++++++---
 include/hw/virtio/virtio-rng.h              |  5 +-
 include/standard-headers/linux/virtio_rng.h | 14 +++
 5 files changed, 111 insertions(+), 14 deletions(-)

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2.23.0