System for safe execution of guest code in virtual machine context includes (a) a virtual machine monitor (VMM) that handles potentially unsafe instructions; (b) a virtual machine (VM) running guest code; (c) wherein the hardware virtualization means handles interrupts when encountering at least some privileged instructions in the guest code, (d) wherein the hardware virtualization means continuously determines, at runtime, if the instruction in the guest code is safe or potentially unsafe, wherein the potentially unsafe instructions are non-privileged instructions that can execute incorrectly in a context of the VM; (e) wherein the VM executes the safe instructions in a native mode; (f) wherein the hardware virtualization means bypasses potentially unsafe instructions.