[PATCH RFC 0/1] Hypercall UCALL for guest/userspace communication

[Forrest Yuan Yu <yuanyu@google.com>]

This RFC is to add a hypercall UCALL so that guest can communicate with
the userspace hypervisor. A guest may want to do this in different
scenarios. For example, a guest can ask the userspace hypervisor to
harden security by setting restricted access permissions on guest SLAT
entries.

Please note this hypercall provides the infrastructure for this type of
communication but does not enforce the protocol. A proposal for the
guest/userspace communication protocol will follow if this RFC is
accepted.

Forrest Yuan Yu (1):
  KVM: x86: add KVM_HC_UCALL hypercall

 Documentation/virt/kvm/api.rst                |  15 +-
 Documentation/virt/kvm/cpuid.rst              |   3 +
 Documentation/virt/kvm/hypercalls.rst         |  14 ++
 arch/x86/include/asm/kvm_host.h               |   1 +
 arch/x86/include/uapi/asm/kvm_para.h          |   1 +
 arch/x86/kvm/x86.c                            |  39 +++-
 include/uapi/linux/kvm.h                      |   1 +
 include/uapi/linux/kvm_para.h                 |   1 +
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/x86_64/hypercall_ucall.c    | 195 ++++++++++++++++++
 11 files changed, 264 insertions(+), 8 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/x86_64/hypercall_ucall.c

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2.26.2.526.g744177e7f7-goog