Patent ID: 8473946

Claim:
A method for storing the output of non-deterministic instructions during record mode by a guest virtual machine (VM) in a virtualized computer system, the VM having a guest operating system executing via virtualization software, the virtualization software running on a host platform having a CPU, the method comprising: (a) the CPU executing a non-deterministic guest instruction for the guest VM while the CPU is in a guest VM context and while the guest VM is executing in record mode; (b) the CPU obtaining a non-deterministic value resulting from the executing of the non-deterministic guest instruction; (c) the CPU storing the non-deterministic value to a buffer while the CPU is in the guest VM context without switching to a hypervisor context, wherein the buffer is accessible by the CPU; (d) repeating steps (a) through (c) multiple times, all while the CPU is in the quest context; and then (e) switching from the guest VM context to the hypervisor context and copying at least some of the contents of the buffer to a log, wherein the log is accessible by the hypervisor.