On Fri, Sep 22, 2023 at 3:53 AM Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > > On Thu, Sep 21, 2023 at 03:34:03PM -0400, Michael S. Tsirkin wrote: > > > that's easy/practical. If instead VDPA gives the same speed with just > > shadow vq then keeping this hack in vfio seems like less of a problem. > > Finally if VDPA is faster then maybe you will reconsider using it ;) > > It is not all about the speed. > > VDPA presents another large and complex software stack in the > hypervisor that can be eliminated by simply using VFIO. vDPA supports standard virtio devices so how did you define complexity? >From the view of the application, what it wants is a simple virtio device but not virtio-pci devices. That is what vDPA tries to present. By simply counting LOCs: vdpa + vhost + vp_vdpa is much less code than what VFIO had. It's not hard to expect, it will still be much less even if iommufd is done. Thanks > VFIO is > already required for other scenarios. > > This is about reducing complexity, reducing attack surface and > increasing maintainability of the hypervisor environment. > > Jason > >
