This paper introduces an SMP protocol for the home-based software DSM system JIAJIA. In the protocol, intra-node processes in an SMP node share their home pages through hardware coherent sharing so as to take the full advantage of the home effect of home-based software DSMs. In contrast, cached remote pages of a process are not shared by its intra-node partners to avoid cache page conflict within an SMP. Besides, JIAJIA also implements the shared memory communication among processes within the same SMP node to accelerate intra-node communication. Performance evaluation with some well accepted benchmarks and real applications in a cluster of four two-processor nodes shows that the SMP protocol of JIAJIA reduces remote accesses, diffs, and consequently message amounts in all of the ten benchmarks and as a result obtains noticeable performance improvement in seven.