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? Thanks, Stefan
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