On Mon, May 25, 2020 at 4:34 PM Cindy Lu <l...@redhat.com> wrote: > On Thu, May 21, 2020 at 8:40 PM Stefan Hajnoczi <stefa...@gmail.com> wrote: > > On Sat, May 09, 2020 at 12:32:14AM +0800, Cindy Lu wrote: > > > From: Tiwei Bie <tiwei....@intel.com> > > > > > > Currently we have 2 types of vhost backends in QEMU: vhost kernel and > > > vhost-user. The above patch provides a generic device for vDPA purpose, > > > this vDPA device exposes to user space a non-vendor-specific configuration > > > interface for setting up a vhost HW accelerator, this patch set introduces > > > a third vhost backend called vhost-vdpa based on the vDPA interface. > > > > > > Vhost-vdpa usage: > > > > > > qemu-system-x86_64 -cpu host -enable-kvm \ > > > ...... > > > -netdev type=vhost-vdpa,vhostdev=/dev/vhost-vdpa-id,id=vhost-vdpa0 \ > > > -device virtio-net-pci,netdev=vhost-vdpa0,page-per-vq=on \ > > > > I haven't looked at vDPA in depth. What is different here compared to > > the existing vhost-backend.c kernel backend? > > > > It seems to be making the same ioctls calls so I wonder if it makes > > sense to share the vhost-backend.c kernel code? > > > > Stefan > Hi Stefan, > Sorry for the late reply and Thanks for these suggestions. > I think the most difference between vhost kernel and vdpa is vdpa > depends on a real hardware. > The point is that vDPA devices work as a virtio device, but vhost-vdpa > qemu must present a vhost-like device in qemu vhost layer. > The ioctl calls are similar with vhost-backend.c now, but after more > and more NIC support vdpa. The difference between vhost-backend.c and > vpda will become more and more big. It will make the code complicated > to share the code with kernel code.
Okay, thanks. Stefan
