The kernel task has the privilege to copy data from any part of physical memory to any other part. To copy from virtual address A in process 1's address space to a virtual address B in process 2's address space, the kernel task needs to know

• the virtual address A and the process (1)
• the virtual address B and the process (2)
• the number of bytes to copy

The system task could then copy the data as follows

• translate virtual address A to a physical address
• translate virtual address B to a physical address
• copies the specified bytes from physical address to physical address