RE: [virtio-comment] [PROPOSAL] Virtio Over Fabrics(TCP/RDMA)

[Parav Pandit <parav@nvidia.com>]

> From: Jason Wang <jasowang@redhat.com>
> Sent: Tuesday, April 25, 2023 2:31 AM

> >> 2, Typical virtualization environment. The workloads run in a guest,
> >> and QEMU handles virtio-pci(or MMIO), and forwards requests to target.
> >> ÂÂÂÂÂÂÂÂ +----------+ÂÂÂ +----------+ÂÂÂÂÂÂ +----------+
> >>  |Map-Reduce| | nginx | ... | processes|
> >> ÂÂÂÂÂÂÂÂ +----------+ÂÂÂ +----------+ÂÂÂÂÂÂ +----------+
> >> ------------------------------------------------------------
> >> GuestÂÂÂÂÂÂÂ |ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | KernelÂÂ +-------+
> >> +-------+ÂÂÂÂÂÂÂÂÂ +-------+
> >> ÂÂÂÂÂÂÂÂÂ | ext4Â |ÂÂÂÂÂÂ | LKCFÂ |ÂÂÂÂÂÂÂÂÂ | HWRNG |
> >> ÂÂÂÂÂÂÂÂÂ +-------+ÂÂÂÂÂÂ +-------+ÂÂÂÂÂÂÂÂÂ +-------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> >> ÂÂÂÂÂÂÂÂÂ +-------+ÂÂÂÂÂÂ +-------+ÂÂÂÂÂÂÂÂÂ +-------+
> >>  | vdx | |vCrypto| | vRNG |
> >> ÂÂÂÂÂÂÂÂÂ +-------+ÂÂÂÂÂÂ +-------+ÂÂÂÂÂÂÂÂÂ +-------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | PCI
> >> --------------------------------------------------------
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> >> QEMUÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ +--------------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |virtio backend|
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ +--------------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ +------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |NIC/IB|
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ +------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | +-------------+
> >> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ +--------------------->|virtio target|
> >> +-------------+
> >>

> > Use case 1 and 2 can be achieved directly without involving any
> > mediation layer or any other translation layer (for example virtio to
> > nfs).
> 
> 
> Not for at least use case 2? It said it has a virtio backend in Qemu. Or the only
> possible way is to have virtio of in the guest.
>
Front end and back end both are virtio. So There is some layer of mediation/translation from PCI to fabric commands.
But not as radical as virtio blk to nfs or virtio blk to nvme.