Andrew Stiegmann of VMware has pushed out a set of eleven patches under an "RFC" (Request For Comments) flag as "In an effort to improve the out-of-the-box experience with Linux kernels for VMware users, VMware is working on readying the Virtual Machine Communication Interface (vmw_vmci) and VMCI Sockets (vmw_vsock) kernel modules for inclusion in the Linux kernel."
As far as what VMware VMCI is, below is the description that was part of the patch series descriptions on the kernel mailing list.
VMCI allows virtual machines to communicate with host kernel modules and the VMware hypervisors. User level applications both in a virtual machine and on the host can use vmw_vmci through VMCI Sockets, a socket address family designed to be compatible with UDP and TCP at the interface level. Today, VMCI and VMCI Sockets are used by the VMware shared folders (HGFS) and various VMware Tools components inside the guest for zero-config, network-less access to VMware host services. In addition to this, VMware's users are using VMCI Sockets for various applications, where network access of the virtual machine is restricted or non-existent. Examples of this are VMs communicating with device proxies for proprietary hardware running as host applications and automated testing of applications running within virtual machines.VMware already has several of its virtualization components integrated into the mainline Linux kernel, but it's good to see more support code coming.
While VMware's virtualization products aren't open-source or free as in free beer (sans the VMware Player), at least on the desktop front it's not without its own set of advantages. Over KVM/QEMU, VMware virtualization allows for 3D/video acceleration on guest virtual machines that is accelerated on the hardware by the host. The OpenGL stack is open-source with the virtual GPU components being integrated into the mainline Linux kernel DRM and Mesa Gallium3D. It's open-source, works with the mainline components, and performs quite well. I'm quite a fan of using VMware for its accelerated OpenGL guest benefits compared to VMware/KVM currently not providing any form of 3D acceleration (I use VMware Fusion on my main business system). With VMware, things tend to "just work" from a clean install and then enhanced when installing the guest kernel modules, but now it should work even better out-of-the-box when the VMCI code is merged. This could possibly happen for the Linux 3.5 kernel and weighs in at around 15,000 lines of new code with the vmw_vmci module.
Meanwhile, Oracle hasn't been working lately on merging any of its guest additions into the mainline Linux kernel. They would have a tough time merging the VirtualBox modules anyways since the upstream Linux kernel developers view them as tainted crap.