tests/plugin: expand insn test to detect duplicate instructions

A duplicate insn is one that is appears to be executed twice in a row.
This is currently possible due to -icount and cpu_io_recompile()
causing a re-translation of a block. On it's own this won't trigger
any tests though.

The heuristics that the plugin use can't deal with the x86 rep
instruction which (validly) will look like executing the same
instruction several times. To avoid problems later we tweak the rules
for x86 to run the "inline" version of the plugin. This also has the
advantage of increasing coverage of the plugin code (see bugfix in
previous commit).

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210213130325.14781-15-alex.bennee@linaro.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/tests/plugin/insn.c b/tests/plugin/insn.c
index a9a6e41..c253980 100644
--- a/tests/plugin/insn.c
+++ b/tests/plugin/insn.c
@@ -21,6 +21,14 @@ static bool do_inline;
 
 static void vcpu_insn_exec_before(unsigned int cpu_index, void *udata)
 {
+    static uint64_t last_pc;
+    uint64_t this_pc = GPOINTER_TO_UINT(udata);
+    if (this_pc == last_pc) {
+        g_autofree gchar *out = g_strdup_printf("detected repeat execution @ 0x%"
+                                                PRIx64 "\n", this_pc);
+        qemu_plugin_outs(out);
+    }
+    last_pc = this_pc;
     insn_count++;
 }
 
@@ -36,8 +44,10 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
             qemu_plugin_register_vcpu_insn_exec_inline(
                 insn, QEMU_PLUGIN_INLINE_ADD_U64, &insn_count, 1);
         } else {
+            uint64_t vaddr = qemu_plugin_insn_vaddr(insn);
             qemu_plugin_register_vcpu_insn_exec_cb(
-                insn, vcpu_insn_exec_before, QEMU_PLUGIN_CB_NO_REGS, NULL);
+                insn, vcpu_insn_exec_before, QEMU_PLUGIN_CB_NO_REGS,
+                GUINT_TO_POINTER(vaddr));
         }
     }
 }