SECURE ARBITRATION MODE TO BUILD AND OPERATE WITHIN TRUST DOMAIN EXTENSIONS

A processor comprising decode circuitry to decode a SEAMCALL instruction for a virtual machine monitor (VMM) in legacy VMX root operation mode; and execution circuitry to perform operations corresponding to the SEAMCALL instruction, including to: cause a virtual machine (VM) exit; transition the processor from the legacy VMX root operation mode to a secure arbitration mode (SEAM) VMX root operation mode, wherein a SEAM module is to be hosted in the SEAM VMX root operation mode; store a VMM state of the processor to a virtual machine control structure (VMCS); load a SEAM module state of the processor from the VMCS; inhibit system management interrupts (SMI) and non-maskable interrupts (NMI) in the SEAM VMX root operation mode; and invoke the SEAM module. A system comprising a system memory; and said processor as stated above.