[RFC PATCH v2 0/4] KVM: VM Planes host support for VBS

[Sriram Nambakam <snambakam@linux.microsoft.com>]

This RFC adds the KVM host support needed to run Virtualization-Based
Security (VBS) across KVM VM Planes.  The series reserves the VM Plane and
VTL hypercalls, exits plane configuration and activation to userspace,
adds shared VTL-call state, and handles VTL call/return with an in-kernel
plane switch.

This is v2 of the series.  Based on feedback from maintainers, the KVM
host, guest, and QEMU changes are now being posted as three separate,
layered RFCs to make it easier to understand the context of these
changes as they pertain to the KVM host, guest, and QEMU.  This
patchset does not yet include memory protection between planes; that
will be added in a future version.

This series is based on the KVM VM Planes prerequisite patchset obtained
from Joerg Roedel's tree (kvm-planes-v7.1):
https://github.com/joergroedel/linux/tree/kvm-planes-v7.1

The dependent guest-side VBS support is being posted as a separate RFC.
This remains prototype code and is not intended for production use.

The implementation and integration tooling are available at:

  Linux and KVM support:
  https://github.com/safe-tee/linux/tree/vm-planes-layered

  QEMU support:
  https://github.com/safe-tee/qemu/tree/vm-planes-layered

  Build, test, and integration tooling:
  https://github.com/safe-tee/lvbs

Acknowledgments
===============

This work stands on top of, and is indebted to, several prior efforts:

  - Joerg Roedel, whose QEMU and KVM VM Planes work provides the
    infrastructure that the VBS/VSM secure plane relies on.

  - Paolo Bonzini, whose "[RFC PATCH 00/29] KVM: VM planes" introduced
    the VM Plane concept to KVM as a common in-kernel model for AMD VMPLs,
    Intel TDX partitions, Hyper-V VTLs, and Arm CCA planes.
    https://lwn.net/Articles/1016113/

  - James Bottomley and James Morris, for their ongoing VSM-on-KVM work,
    which informed the design and direction of this series.

Feedback on the hypercall ABI, userspace exits, and in-kernel plane-switch
handling is welcome.

Sriram Nambakam (4):
  kvm: uapi: reserve VM-plane and VBS hypercall numbers
  KVM: x86: exit VM-plane config/activate hypercalls to userspace
  KVM: x86: add VTL-call state to struct kvm_vcpu_common
  KVM: x86: handle VBS VTL call/return via in-kernel plane switch

 arch/x86/kvm/x86.c            | 88 ++++++++++++++++++++++++++++++++++-
 include/linux/kvm_host.h      |  5 ++
 include/uapi/linux/kvm_para.h |  4 ++
 3 files changed, 96 insertions(+), 1 deletion(-)


base-commit: ca4f6f8de47d9b9d9c3fc613668ec72579ba111c
-- 
2.55.0