1. A system, comprising: at least one computing device; a first virtual machine executable by the at least one computing device; a second virtual machine executable by the at least one computing device; a shadow memory that stores taint bits which represent memory and all CPU registers at byte granularity level; an interrupt handler; and an introspection system executable by the at least one computing device, the introspection system being configured to: determine that an introspection program executed by the first virtual machine is requested to introspect the second virtual machine; determine, by the interrupt handler, a start and end of an interrupt by using a counter that 1) is initialized to zero, 2) is incremented when a non-system call interrupt executes, and 3) is decremented when an interrupt return instruction executes, wherein 1) the start of the interrupt occurs when a first non-system call interrupt executes, 2) the end of the interrupt occurs when the counter returns to a value of zero, 3) each non-system call interrupt may have one or more nested non-system call interrupts, and 4) each non-system call interrupt is returned using a respective interrupt return instruction; and determine, using the determined start and end of the interrupt, a system call execution context of the introspection program in response to determining that the introspection program is requested to introspect the second virtual machine, the system call execution context being determined by isolating a kernel space of the introspection program from an inspection of a control register value, the control register value being acquired based at least in part on an update of the control register value in response to an execution of a system call for the introspection program; initialize all the taint bits to zero; use the isolated kernel space to assign a plurality of the taint bits in the shadow memory a value of one, wherein the value of one indicates the corresponding byte of memory or CPU register contains redirectable data; identify, using the taint bits in shadow memory, redirectable data in a memory of the second virtual machine based at least in part on the system call execution context of the introspection program, the redirectable data being redirectable to a portion of the memory of the first virtual machine; and configure the introspection program to access the redirectable data.