Difftest: add xtval to DisambiguationState

* It will help NEMU force IPF treat cross-page IPF correctly

src/test/csrc/difftest.cpp

@@ -191,6 +191,10 @@ int difftest_step(DiffState *s) {
         // IPF, LPF, SPF
         if(s->cause == 12 || s->cause == 13 || s->cause == 15){
           // printf("s->cause %ld\n", s->cause);
+          struct DisambiguationState ds;
+          ds.exceptionNo = s->cause;
+          ds.mtval = s->reg_scala[DIFFTEST_MTVAL];
+          ds.stval = s->reg_scala[DIFFTEST_STVAL];
           ref_disambiguate_exec(&s->cause);
         }else{
           ref_difftest_exec(1);

src/test/csrc/difftest.h

@@ -68,6 +68,12 @@ struct DiffState {
   // this will lead to different sc results.
 };
 
+struct DisambiguationState {
+  uint64_t exceptionNo;
+  uint64_t mtval;
+  uint64_t stval;
+};
+
 extern void (*ref_difftest_memcpy_from_dut)(paddr_t dest, void *src, size_t n);
 extern void (*ref_difftest_memcpy_from_ref)(void *dest, paddr_t src, size_t n);
 extern void (*ref_difftest_getregs)(void *c);