Method for controlling file input-output in virtualization system

A paravirtualization system for protecting a paravirtualized agent, the system comprising:

• a parser configured to parse a file system of a guest operating system (OS) and to verify an integrity of the paravirtualized agent, wherein a virtual machine operates both the guest OS and the paravirtualized agent, and wherein the parser parses the guest OS's file system prior to the virtual machine being started so that verifying the integrity of the paravirtualized agent is performed before the paravirtualized agent is executed;
• a host-based file system protection service (HFPS) configured to block a modulation of a memory area to which the paravirtualized agent is allocated when the paravirtualized agent is determined to have integrity based on a result of the verifying, wherein blocking the modulation of the memory area is performed by:
• determining an execution start time of the paravirtualized agent, and
• prior to that execution start time, starting a process in which modulations are obstructed from being performed on the memory area such that the modulation is obstructed from being performed on the memory area even prior to the paravirtualized agent's execution start time;
• the paravirtualized agent, which is configured to operate in the virtual machine, and which, in response to an occurrence of a file input/output (I/O), is configured to inquire about an accessibility by transmitting information on the occurring file I/O;
• and
• a reasoning engine configured to verify a right to access the occurring file I/O and to transmit a result of the verifying of the occurring file I/O to the paravirtualized agent.