On 12/6/2014 3:01 AM, Aashima Arora wrote: > Hi, > I was trying to access the pci config space(BAR) of the virtual function > device visible in the virtual machine, similar to what DPDK does on host > via both UIO and VFIO. Did the following steps. > > 1. Bound PF Drivers to ixgbe and spawned virtual function drivers , bound > them to vfio-pci and set their mac addresses via ip link. Ran Qemu and > assigned the VF Device using vfio-pci device assignment and initialized the > virtual machine. > insmod igb max_vfs=2 > > ./x86_64-softmmu/qemu-system-x86_64 -cpu host -boot c -hda > /home/vm-images/vm2.imgsnapshot -m 2048M -smp 2 --enable-kvm -name 'vm2' > -vnc :2 -pidfile /tmp/vm2.pid -driile=fat:rw:/tmp/share,snapshot=off > -device vfio-pci,host=01:10.1,id=net1 > > > 2. The VF Device was visible with another pci address. > > 00:04.0 Ethernet controller: Intel Corporation 82599ES 10-Gigabit SFI/SFP+ > Network > Connection (rev 01) > > Further ran DPDK testpmd on top of VM but bound the virtual function driver > to igb_uio instead of vfio-pci. It ran successfully. The ixgbevf pmd > driver is able to access the BAR registers in pci_uio_map_resource via > mmaping somewhere close to hugepages. I was not able to bind the virtual > function driver in VM to vfio-pci and hence DPDK would not be able to run > with VFIO enabled as it complains of no IOMMU support. I also believe that > there is little logic in binding the vf device to vfio-pci again since qemu > has already taken care of it and hardware support is involved. > > So my questions are > a. vfio is meant to be a replacement for both uio and device assignment > for qemu. This doesnt seem simultaneous. Comment?
What do you mean "device assignment" ? You mean pass-through? > b. Is there any way to access VF device using VFIO in guest userspace? > Have you run DPDK in guest machine with VFIO support enabled and all > dependent modules inserted and did it work? As I knows, the answer is *NO*, because the iommu is not support in guest. > c. Is igb_uio or uio_pci_generic in future the only way to access the > device in guest userspace? It depends, who knows what will happen in future :) Thanks, Michael > *Regards* >
