plugins/api Add APIs for memory and register reads

include/qemu/qemu-plugin.h

@@ -355,8 +355,29 @@ size_t qemu_plugin_tb_n_insns(const struct qemu_plugin_tb *tb);
 uint64_t qemu_plugin_tb_vaddr(const struct qemu_plugin_tb *tb);
 
 /**
- * qemu_plugin_import_function() - return pointer to a function in another
- * plugin
+ * qemu_plugin_get_pc() - returns current program counter
+ *
+ */
+uint64_t qemu_plugin_get_pc(void);
+
+/**
+ * qemu_plugin_get_reg32() - returns a 32-bit register
+ * @reg_idx: register index
+ * @error: set to true if an error occurs
+ *
+ */
+int32_t qemu_plugin_get_reg32(unsigned int reg_idx, bool* error);
+
+/**
+ * qemu_plugin_get_reg64() - returns a 64-bit register
+ * @reg_idx: register index
+ * @error: set to true if an error occurs
+ *
+ */
+int64_t qemu_plugin_get_reg64(unsigned int reg_idx, bool* error);
+
+/**
+ * qemu_plugin_import_function() - return pointer to a function in another plugin
  * @plugin: plugin name
  * @function: function name
  *
@@ -410,6 +431,16 @@ bool qemu_plugin_reg_callback(const char *target_plugin, const char *cb_name,
 bool qemu_plugin_unreg_callback(const char *target_plugin, const char *cb_name,
                                 cb_func_t function_pointer);
 
+/**
+ * qemu_plugin_read_guest_virt_mem() - Read a buffer of guest memory
+ * @gva: Guest virtual address
+ * @buf: Buffer to copy guest memory into
+ * @length: Size of buf
+ *
+ * Returns: True if the memory was successfully copied into buf
+ */
+bool qemu_plugin_read_guest_virt_mem(uint64_t gva, char* buf, size_t length);
+
 /**
  * qemu_plugin_tb_get_insn() - retrieve handle for instruction
  * @tb: opaque handle to TB passed to callback

plugins/api.c

@@ -52,6 +52,7 @@
 #endif
 #endif
 
+
 /* Uninstall and Reset handlers */
 
 void qemu_plugin_uninstall(qemu_plugin_id_t id, qemu_plugin_simple_cb_t cb)
@@ -205,6 +206,76 @@ qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx)
     return insn;
 }
 
+/*
+ * Register information
+ *
+ * These queries allow the plugin to retrieve information about each
+ * the current state of registers in the CPU
+ */
+
+uint64_t qemu_plugin_get_pc(void) {
+    CPUState *cpu = current_cpu;
+    CPUArchState *env = (CPUArchState *)cpu->env_ptr;
+    target_ulong pc, cs_base;
+    uint32_t flags;
+    cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
+    return (uint64_t)pc;
+}
+
+bool qemu_plugin_read_guest_virt_mem(uint64_t gva, char* buf, size_t length) {
+#ifdef CONFIG_USER_ONLY
+  return false;
+#else
+    // Convert virtual address to physical, then read it
+    CPUState *cpu = current_cpu;
+    uint64_t page = gva & TARGET_PAGE_MASK;
+    hwaddr gpa = cpu_get_phys_page_debug(cpu, page);
+    if (gpa == (hwaddr)-1) {
+        return false;
+    }
+
+    gpa += (gva & ~TARGET_PAGE_MASK);
+    cpu_physical_memory_rw(gpa, buf, length, false);
+    return true;
+#endif
+}
+
+int32_t qemu_plugin_get_reg32(unsigned int reg_idx, bool* error) {
+    // Should we directly use gdbsub.c's gdb_read_register?
+    CPUState *cpu = current_cpu;
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+    GByteArray* result = g_byte_array_sized_new(4);
+
+    int32_t rv = 0;
+    int bytes_read = cc->gdb_read_register(cpu, result, reg_idx);
+    *error = (bytes_read == 0);
+    if (*error) {
+      return 0;
+    }
+    memcpy(&rv, result->data, sizeof(rv));
+
+    g_byte_array_free(result, true);
+    return rv;
+}
+
+int64_t qemu_plugin_get_reg64(unsigned int reg_idx, bool* error) {
+    // Should we directly use gdbsub.c's gdb_read_register?
+    CPUState *cpu = current_cpu;
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+    GByteArray* result = g_byte_array_sized_new(8);
+
+    int64_t rv = 0;
+    int bytes_read = cc->gdb_read_register(cpu, result, reg_idx);
+    *error = (bytes_read == 0);
+    if (*error) {
+      return 0;
+    }
+
+    memcpy(&rv, result->data, sizeof(rv));
+    g_byte_array_free(result, true);
+    return rv;
+}
+
 /*
  * Instruction information
  *

plugins/qemu-plugins.symbols

@@ -3,6 +3,9 @@
   qemu_plugin_end_code;
   qemu_plugin_entry_code;
   qemu_plugin_get_hwaddr;
+  qemu_plugin_get_reg32;
+  qemu_plugin_get_reg64;
+  qemu_plugin_get_pc;
   qemu_plugin_import_function;
   qemu_plugin_create_callback;
   qemu_plugin_run_callback;
@@ -25,6 +28,7 @@
   qemu_plugin_n_vcpus;
   qemu_plugin_outs;
   qemu_plugin_path_to_binary;
+  qemu_plugin_read_guest_virt_mem;
   qemu_plugin_register_atexit_cb;
   qemu_plugin_register_flush_cb;
   qemu_plugin_register_vcpu_exit_cb;