Re: [Qemu-devel] [RFC 0/2] virtio-vhost-user: add virtio-vhost-user device

[Wei Wang]

On 01/19/2018 09:06 PM, Stefan Hajnoczi wrote:
> These patches implement the virtio-vhost-user device design that I have
> described here:
> https://stefanha.github.io/virtio/vhost-user-slave.html#x1-2830007
>
>
>   configure                                   |   18 +
>   hw/virtio/Makefile.objs                     |    1 +
>   hw/virtio/virtio-pci.h                      |   21 +
>   include/hw/pci/pci.h                        |    1 +
>   include/hw/virtio/vhost-user.h              |  106 +++
>   include/hw/virtio/virtio-vhost-user.h       |   88 +++
>   include/standard-headers/linux/virtio_ids.h |    1 +
>   hw/virtio/vhost-user.c                      |  100 +--
>   hw/virtio/virtio-pci.c                      |   61 ++
>   hw/virtio/virtio-vhost-user.c               | 1047 +++++++++++++++++++++++++++
>   hw/virtio/trace-events                      |   22 +
>   11 files changed, 1367 insertions(+), 99 deletions(-)
>   create mode 100644 include/hw/virtio/vhost-user.h
>   create mode 100644 include/hw/virtio/virtio-vhost-user.h
>   create mode 100644 hw/virtio/virtio-vhost-user.c

Thanks for the quick implementation. Not sure if the following issues 
could be solved with this approach:
 - After we boot the slave VM, if we don't run the virtio-vhost-user 
driver (i.e. testpmd), then the master VM couldn't boot, because the 
booting of the virtio-net device relies on a negotiation with the 
virtio-vhost-user driver.
 - Suppose in the future there is also a kernel virtio-vhost-user 
driver as other PCI devices, can we unbind the kernel driver first, and 
then bind the device to the dpdk driver? A normal PCI device should be 
able to smoothly switch between the kernel driver and dpdk driver.

Best,
Wei