On Mon, 02 Jan 2017 15:32:08 +0100 Thomas Monjalon <thomas.monja...@6wind.com> wrote:
> 2016-12-29 17:14, Stephen Hemminger: > > On Thu, 29 Dec 2016 20:41:21 +0000 > > "Walker, Benjamin" <benjamin.wal...@intel.com> wrote: > > > My second question is whether the user should be allowed to > > > mix uio and vfio usage simultaneously. For vfio, the > > > physical addresses are really DMA addresses and are best > > > when arbitrarily chosen to appear sequential relative to > > > their virtual addresses. For uio, they are physical > > > addresses and are not chosen at all. It seems that these two > > > things are in conflict and that it will be difficult, ugly, > > > and maybe impossible to resolve the simultaneous use of > > > both. > > > > Unless application is running as privileged user (ie root), UIO > > is not going to work. Therefore don't worry about mixed environment. > > Yes, mixing UIO and VFIO is possible only as root. > However, what is the benefit of mixing them? One possible case where this could be used, Hyper-V/Azure and SR-IOV. The VF interface will show up on an isolated PCI bus and the virtual NIC is on VMBUS. It is possible to use VFIO on the PCI to get MSI-X per queue interrupts, but there is no support for VFIO on VMBUS.
