1. A computer-implemented method for allocating memory from a host computer for an add-in card, the method comprising performing, by the host computer, computer-implemented operations for: intercepting a first interrupt for resetting a mass storage device; in response to intercepting the first interrupt for resetting the mass storage device, reading a system address map, modifying the system address map by adding an entry for an amount of host memory to be allocated to the add-in card, storing the modified system address map as a destination system address map, changing an address of a second interrupt handler for handling interrupts for reporting the system address map, and storing an address of an original interrupt handler for handling interrupts for reporting the system address map in a memory of the add-in card; intercepting a second interrupt for reporting the system address map; determining whether the second interrupt is memory related; in response to determining that the second interrupt is memory related, providing the destination system address map; and in response to determining that the second interrupt is not memory related, calling the original interrupt handler at the stored address.