[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <547FC5DE.4010701@intel.com>
Date: Thu, 04 Dec 2014 10:24:30 +0800
From: Jike Song <jike.song@...el.com>
To: "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
kvm@...r.kernel.org, linux-kernel@...r.kernel.org
CC: "Tian, Kevin" <kevin.tian@...el.com>,
"Cowperthwaite, David J" <david.j.cowperthwaite@...el.com>,
"White, Michael L" <michael.l.white@...el.com>,
"Dong, Eddie" <eddie.dong@...el.com>,
"Li, Susie" <susie.li@...el.com>,
"Haron, Sandra" <sandra.haron@...el.com>
Subject: [ANNOUNCE][RFC] KVMGT - the implementation of Intel GVT-g(full GPU
virtualization) for KVM
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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists