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

[Stefan Hajnoczi]

On Fri, Jan 24, 2020 at 03:05:18PM +0100, Laurent Vivier wrote:
> On 24/01/2020 12:02, Stefan Hajnoczi wrote:
> > On Thu, Jan 23, 2020 at 04:16:58PM +0100, Laurent Vivier wrote:
> >> 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(-)
> > 
> > Where can I find the VIRTIO specification for this new virtqueue?
> 
> I didn't update the specs.
> 
> Is https://github.com/oasis-tcs/virtio-spec.git the document to update?

Yes, please.

Stefan

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