Re: [ANNOUNCE] 2015-Q4 release of KVMGT (Was Re: KVMGT - the implementation of ...)

From: Jike Song
Date: Wed Jan 27 2016 - 01:32:26 EST


Hi all,

We are pleased to announce another update of Intel GVT-g for KVM.

Intel GVT-g for KVM (a.k.a. KVMGT) is a full GPU virtualization solution with mediated pass-through, starting from 4th generation Intel Core(TM) processors with Intel Graphics processors. 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 among performance, feature, and sharing capability.

Repositories:

Kernel: https://github.com/01org/igvtg-kernel (2015q4-4.2.0 branch)
Qemu: https://github.com/01org/igvtg-qemu (kvmgt_public2015q4 branch)

This update consists of:

- KVMGT now has better support for 5th generation (Broadwell) Intel Core(TM) processors, 2D/3D/Media workloads can be run simultaneously in multiple guests.
- Host Linux kernel has been upgraded from 3.18.0 to 4.2.0 (based on drm-intel)

Next update will be around early April, 2016.

Known issues:

- At least 2GB memory is suggested for VM to run most 3D workloads.
- Using VLC to play .ogg file may cause mosaic or slow response.
- Running heavy 3D workloads in multiple guests for couple of hours may cause stability issue.

Official iGVT-g portal: https://01.org/igvt-g
Please subscribe the mailing list: https://lists.01.org/mailman/listinfo/igvt-g

More information about background, architecture and others about Intel GVT-g, can be found at:

http://www.linux-kvm.org/images/f/f3/01x08b-KVMGT-a.pdf
https://www.usenix.org/conference/atc14/technical-sessions/presentation/tian


Note: The KVMGT project should be considered a work in progress. As such it is not a complete product nor should it be considered one. Extra care should be taken when testing and configuring a system to use the KVMGT project.


--
Thanks,
Jike

On 10/27/2015 05:36 PM, Jike Song wrote:
> Hi all,
>
> We are pleased to announce another update of Intel GVT-g for KVM.
>
> Intel GVT-g is a full GPU virtualization solution with mediated pass-through, starting from 4th generation Intel Core(TM) processors with Intel Graphics processors. 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 among performance, feature, and sharing capability. KVM is supported by Intel GVT-g(a.k.a. KVMGT).
>
>
> Repositories
>
> Kernel: https://github.com/01org/igvtg-kernel (2015q3-3.18.0 branch)
> Qemu: https://github.com/01org/igvtg-qemu (kvmgt_public2015q3 branch)
>
>
> This update consists of:
>
> - KVMGT is now merged with XenGT in unified repositories(kernel and qemu), but currently
> different branches for qemu. KVMGT and XenGT share same iGVT-g core logic.
> - PPGTT supported, hence the Windows guest support
> - KVMGT now supports both 4th generation (Haswell) and 5th generation (Broadwell) Intel Core(TM) processors
> - 2D/3D/Media decoding have been validated on Ubuntu 14.04 and Windows7/Windows 8.1
>
> Next update will be around early Jan, 2016.
>
> Known issues:
>
> - At least 2GB memory is suggested for VM to run most 3D workloads.
> - 3Dmark06 running in Windows VM may have some stability issue.
> - Using VLC to play .ogg file may cause mosaic or slow response.
>
>
> Please subscribe the mailing list to report BUGs, discuss, and/or contribute:
>
> https://lists.01.org/mailman/listinfo/igvt-g
>
> More information about Intel GVT-g background, architecture, etc can be found at(may not be up-to-date):
>
> https://01.org/igvt-g
> http://www.linux-kvm.org/images/f/f3/01x08b-KVMGT-a.pdf
> https://www.usenix.org/conference/atc14/technical-sessions/presentation/tian
>
>
> Note:
>
> The KVMGT project should be considered a work in progress. As such it is not a complete product nor should it be considered one. Extra care should be taken when testing and configuring a system to use the KVMGT project.
>
>
> --
> Thanks,
> Jike
>
> On 12/04/2014 10:24 AM, Jike Song wrote:
>> Hi all,
>>
>> 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.
>>
>>
>> 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://github.com/01org/KVMGT-kernel
>> git://github.com/01org/KVMGT-qemu
>> git://github.com/01org/KVMGT-seabios
>>
>> 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:
>>
>> https://www.usenix.org/conference/atc14/technical-sessions/presentation/tian
>> http://events.linuxfoundation.org/sites/events/files/slides/KVMGT-a%20Full%20GPU%20Virtualization%20Solution_1.pdf
>>
>>
>> Appreciate your comments, BUG reports, and contributions!
>>
>>
>>
>>
>> --
>> Thanks,
>> Jike
>>