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

[Laurent Vivier <lvivier@redhat.com>]

On 29/01/2020 16:43, Stefan Hajnoczi wrote:
> 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.

I've updated the specs,

Following
https://github.com/oasis-tcs/virtio-spec/blob/master/CONTRIBUTING.md,
I've opened an issue:

https://github.com/oasis-tcs/virtio-spec/issues/83

Is this the good process?

Thanks,
Laurent