On Wed, Nov 06, 2024 at 12:38:02PM +0000, Srujana Challa wrote: > It is going in circles, let me give the summary, > Issue: We need to address the lack of no-IOMMU support in the vhost vDPA driver for better performance. > Measured Performance: On the machine "13th Gen Intel(R) Core(TM) i9-13900K, 32 Cores", we observed Looks ike you are going in circles indeed. Lack of performance is never a reason to disable the basic memoy safety for userspace drivers. The (also quite bad) reason why vfio-nummu was added was to support hardware entirely with an iommu. There is absolutely no reason to add krnel code for new methods of unsafer userspace I/O without an IOMMU ever.
