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 -- 2.26.2.526.g744177e7f7-goog
