On Mon, Jun 07, 2021 at 03:25:32AM +0000, Tian, Kevin wrote: > > Possibly just a naming thing, but I feel it's better to just talk about > no-snoop or non-coherent in the uAPI. Per Intel SDM wbinvd is a > privileged instruction. A process on the host has no privilege to > execute it. Only when this process holds a VM, this instruction matters > as there are guest privilege levels. But having VFIO uAPI (which is > userspace oriented) to explicitly deal with a CPU instruction which > makes sense only in a virtualization context sounds a bit weird... More importantly the Intel instructions here are super weird. Pretty much every other architecture just has plan old cache writeback/invalidate/writeback+invalidate instructions without all these weird implications.
