Research On Improving Mechanism Of Precise Exception Of QEMU

QEMU is a dynamic binary translator, but there are some deficiencies in supporting the precise exception. When exception happens, it does not completely restore the CPU state, does not locate the position of exception.Against the lack of QEMU support the precise exception, common exception handling system gives a way to improve the mechanism of the precise exception of QEMU. Common exception handling system divides the exceptions into two parts, one part is called predictable exception and the other part is called unpredictable exception. Using set exception point method to deal with predictable exception and using compute exception point method to deal with unpredictable exception. In the end common exception handling system realizes to locate the position of exception of user mode of QEMU.Precise Exception handling system integrates the remote debugging of QEMU, it will respond to the requests of the GDB commands if it connect to the GDB and monitor the state of the process of debugging. It will return the result to the web if the exception happens and it has the features of strong user interaction, simplifies the operations, therefore it is very useful.Result shows common exception handling system realizes to locate the position of exception instruction. Compared with GDB, common exception handling system could locate the position of BOUND exception but GDB could not do it. On the other hand, common exception handling system could give the reasons of exception but GDB could not do it. In the end, common could give the state of general registers and EFLAGS once, but GDB must spend more time to get this information by setting break points. Therefore, common exception handling exception provides faster and more information than GDB, it raises the efficiency when programmers debug the programs.