On Dec 4, 2014 5:27 AM, "Jike Song" <<a href="mailto:jike.song@intel.com">jike.song@intel.com</a>> wrote: > > Hi all, Hi, > > We are pleased to announce the first release of KVMGT project. KVMGT is the implementation of Intel GVT-g technology, a full GPU virtualization solution. Under Intel GVT-g, a virtual GPU instance is maintained for each VM, with part of performance critical resources directly assigned. The capability of running native graphics driver inside a VM, without hypervisor intervention in performance critical paths, achieves a good balance of performance, feature, and sharing capability. Sounds great. > > > KVMGT is still in the early stage: > > - Basic functions of full GPU virtualization works, guest can see a full-featured vGPU. > We ran several 3D workloads such as lightsmark, nexuiz, urbanterror and warsow. > > - Only Linux guest supported so far, and PPGTT must be disabled in guest through a > kernel parameter(see README.kvmgt in QEMU). > > - This drop also includes some Xen specific changes, which will be cleaned up later. > > - Our end goal is to upstream both XenGT and KVMGT, which shares ~90% logic for vGPU > device model (will be part of i915 driver), with only difference in hypervisor > specific services > > - insufficient test coverage, so please bear with stability issues :) > > > > There are things need to be improved, esp. the KVM interfacing part: > > 1 a domid was added to each KVMGT guest > > An ID is needed for foreground OS switching, e.g. > > # echo <domid> > /sys/kernel/vgt/control/foreground_vm > > domid 0 is reserved for host OS. > > > 2 SRCU workarounds. > > Some KVM functions, such as: > > kvm_io_bus_register_dev > install_new_memslots > > must be called *without* &kvm->srcu read-locked. Otherwise it hangs. > > In KVMGT, we need to register an iodev only *after* BAR registers are > written by guest. That means, we already have &kvm->srcu hold - > trapping/emulating PIO(BAR registers) makes us in such a condition. > That will make kvm_io_bus_register_dev hangs. > > Currently we have to disable rcu_assign_pointer() in such functions. > > These were dirty workarounds, your suggestions are high welcome! > > > 3 syscalls were called to access "/dev/mem" from kernel > > An in-kernel memslot was added for aperture, but using syscalls like > open and mmap to open and access the character device "/dev/mem", > for pass-through. > > > > The source codes(kernel, qemu as well as seabios) are available at github: > > git://<a href="http://github.com/01org/KVMGT-kernel">github.com/01org/KVMGT-kernel</a> > git://<a href="http://github.com/01org/KVMGT-qemu">github.com/01org/KVMGT-qemu</a> > git://<a href="http://github.com/01org/KVMGT-seabios">github.com/01org/KVMGT-seabios</a> > > In the KVMGT-qemu repository, there is a "README.kvmgt" to be referred. > > > > More information about Intel GVT-g and KVMGT can be found at: > > <a href="https://www.usenix.org/conference/atc14/technical-sessions/presentation/tian">https://www.usenix.org/conference/atc14/technical-sessions/presentation/tian</a> > <a href="http://events.linuxfoundation.org/sites/events/files/slides/KVMGT-a%20Full%20GPU%20Virtualization%20Solution_1.pdf">http://events.linuxfoundation.org/sites/events/files/slides/KVMGT-a%20Full%20GPU%20Virtualization%20Solution_1.pdf</a> > > > Appreciate your comments, BUG reports, and contributions! I'll prepare fedora builds for testing. Users would do 2 commands to use KVMGT. Feel free to CC me about changes and for testing. I have some devices with Intel graphics. I'll test. > > > > > -- > Thanks, > Jike -- -Igor Gnatenko