On Thu, Sep 21, 2023 at 03:16:37PM -0300, Jason Gunthorpe wrote: > On Thu, Sep 21, 2023 at 01:55:42PM -0400, Michael S. Tsirkin wrote: > > > That's not what I'm asking about though - not what shadow vq does, > > shadow vq is a vdpa feature. > > That's just VDPA then. We already talked about why VDPA is not a > replacement for VFIO. It does however work universally, by software, without any special hardware support. Which is kind of why I am curious - if VDPA needs this proxy code because shadow vq is slower then that's an argument for not having it in two places, and trying to improve vdpa to use iommufd if 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 ;) -- MST
