Init registers for VCPU

Author: Rot127

contrib/plugins/bap-tracing/tracing.c

@@ -7,7 +7,7 @@
 
 static TraceState state;
 
-static void log_insn_exec(unsigned int vcpu_index, void *udata) {
+static void log_insn_reg_access(unsigned int vcpu_index, void *udata) {
   g_rw_lock_reader_lock(&state.vcpus_array_lock);
   // VCPU *c = &g_array_index(state.vcpus, VCPU, vcpu_index);
 
@@ -22,9 +22,43 @@ static void log_insn_exec(unsigned int vcpu_index, void *udata) {
   return;
 }
 
+static Register *init_vcpu_register(qemu_plugin_reg_descriptor *desc)
+{
+    Register *reg = g_new0(Register, 1);
+    g_autofree gchar *lower = g_utf8_strdown(desc->name, -1);
+    int r;
+
+    reg->handle = desc->handle;
+    reg->name = g_intern_string(lower);
+    reg->content = g_byte_array_new();
+
+    /* read the initial value */
+    r = qemu_plugin_read_register(reg->handle, reg->content);
+    g_assert(r > 0);
+    return reg;
+}
+
+static GPtrArray *registers_init(int vcpu_index) {
+  g_autoptr(GPtrArray) registers = g_ptr_array_new();
+  g_autoptr(GArray) reg_list = qemu_plugin_get_registers();
+
+  if (!reg_list->len) {
+    return NULL;
+  }
+  for (int r = 0; r < reg_list->len; r++) {
+    qemu_plugin_reg_descriptor *rd =
+        &g_array_index(reg_list, qemu_plugin_reg_descriptor, r);
+    Register *reg = init_vcpu_register(rd);
+    g_ptr_array_add(registers, reg);
+  }
+
+  return registers->len ? g_steal_pointer(&registers) : NULL;
+}
+
 static void vcpu_init(qemu_plugin_id_t id, unsigned int vcpu_index) {
   g_rw_lock_writer_lock(&state.vcpus_array_lock);
   VCPU *vcpu = calloc(sizeof(VCPU), 1);
+  vcpu->registers = registers_init(vcpu_index);
   g_array_insert_vals(state.vcpus, vcpu_index, &vcpu, 1);
   g_rw_lock_writer_unlock(&state.vcpus_array_lock);
 }
@@ -39,7 +73,7 @@ static void cb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb) {
   size_t n_insns = qemu_plugin_tb_n_insns(tb);
   for (size_t i = 0; i < n_insns; i++) {
     insn = qemu_plugin_tb_get_insn(tb, i);
-    qemu_plugin_register_vcpu_insn_exec_cb(insn, log_insn_exec,
+    qemu_plugin_register_vcpu_insn_exec_cb(insn, log_insn_reg_access,
                                            QEMU_PLUGIN_CB_R_REGS, NULL);
   }
 }

contrib/plugins/bap-tracing/tracing.h

@@ -16,12 +16,18 @@ typedef struct {
 } FrameBuffer;
 
 typedef struct {
-  // Current instruction related things.
+    struct qemu_plugin_register *handle; ///< Passed to qemu API.
+    GByteArray *content;
+    const char *name;
+} Register;
+
+typedef struct {
+  GPtrArray /*<Register>*/ *registers;
 } VCPU;
 
 typedef struct {
   GRWLock vcpus_array_lock;
-  GArray *vcpus;
+  GArray /*<VCPU>*/ *vcpus;
 
   GRWLock frame_buffer_lock;
   FrameBuffer *frame_buffer;