diff mbox series

[v2,09/33] plugins: Copy memory in qemu_plugin_insn_data

Message ID 20240424233131.988727-10-richard.henderson@linaro.org
State New
Headers show
Series accel/tcg: Improve disassembly for target and plugin | expand

Commit Message

Richard Henderson April 24, 2024, 11:31 p.m. UTC 
Instead of returning a host pointer, copy the data into
storage provided by the caller.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/qemu/qemu-plugin.h | 15 +++++++--------
 contrib/plugins/execlog.c  |  5 +++--
 contrib/plugins/howvec.c   |  4 ++--
 plugins/api.c              |  7 +++++--
 4 files changed, 17 insertions(+), 14 deletions(-)

Comments

Philippe Mathieu-Daudé April 29, 2024, 10:40 a.m. UTC | #1 
On 25/4/24 01:31, Richard Henderson wrote:
> Instead of returning a host pointer, copy the data into
> storage provided by the caller.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   include/qemu/qemu-plugin.h | 15 +++++++--------
>   contrib/plugins/execlog.c  |  5 +++--
>   contrib/plugins/howvec.c   |  4 ++--
>   plugins/api.c              |  7 +++++--
>   4 files changed, 17 insertions(+), 14 deletions(-)

>   /**
>    * struct qemu_info_t - system information for plugins
> @@ -394,17 +394,16 @@ struct qemu_plugin_insn *
>   qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx);
>   
>   /**
> - * qemu_plugin_insn_data() - return ptr to instruction data
> + * qemu_plugin_insn_data() - copy instruction data

"copy of "?

>    * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
> + * @dest: destination into which data is copied
> + * @len: length of dest

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
diff mbox series

Patch

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index 4fc6c3739b..5f36c2d1ac 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -61,7 +61,7 @@  typedef uint64_t qemu_plugin_id_t;
 
 extern QEMU_PLUGIN_EXPORT int qemu_plugin_version;
 
-#define QEMU_PLUGIN_VERSION 2
+#define QEMU_PLUGIN_VERSION 3
 
 /**
  * struct qemu_info_t - system information for plugins
@@ -394,17 +394,16 @@  struct qemu_plugin_insn *
 qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx);
 
 /**
- * qemu_plugin_insn_data() - return ptr to instruction data
+ * qemu_plugin_insn_data() - copy instruction data
  * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
+ * @dest: destination into which data is copied
+ * @len: length of dest
  *
- * Note: data is only valid for duration of callback. See
- * qemu_plugin_insn_size() to calculate size of stream.
- *
- * Returns: pointer to a stream of bytes containing the value of this
- * instructions opcode.
+ * Returns the number of bytes copied, minimum of @len and insn size.
  */
 QEMU_PLUGIN_API
-const void *qemu_plugin_insn_data(const struct qemu_plugin_insn *insn);
+size_t qemu_plugin_insn_data(const struct qemu_plugin_insn *insn,
+                             void *dest, size_t len);
 
 /**
  * qemu_plugin_insn_size() - return size of instruction
diff --git a/contrib/plugins/execlog.c b/contrib/plugins/execlog.c
index fab18113d4..371db97eb1 100644
--- a/contrib/plugins/execlog.c
+++ b/contrib/plugins/execlog.c
@@ -258,8 +258,9 @@  static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
                                                        NULL);
             }
         } else {
-            uint32_t insn_opcode;
-            insn_opcode = *((uint32_t *)qemu_plugin_insn_data(insn));
+            uint32_t insn_opcode = 0;
+            qemu_plugin_insn_data(insn, &insn_opcode, sizeof(insn_opcode));
+
             char *output = g_strdup_printf("0x%"PRIx64", 0x%"PRIx32", \"%s\"",
                                            insn_vaddr, insn_opcode, insn_disas);
 
diff --git a/contrib/plugins/howvec.c b/contrib/plugins/howvec.c
index 94bbc53820..9be67f7453 100644
--- a/contrib/plugins/howvec.c
+++ b/contrib/plugins/howvec.c
@@ -252,7 +252,7 @@  static struct qemu_plugin_scoreboard *find_counter(
 {
     int i;
     uint64_t *cnt = NULL;
-    uint32_t opcode;
+    uint32_t opcode = 0;
     InsnClassExecCount *class = NULL;
 
     /*
@@ -261,7 +261,7 @@  static struct qemu_plugin_scoreboard *find_counter(
      * They would probably benefit from a more tailored plugin.
      * However we can fall back to individual instruction counting.
      */
-    opcode = *((uint32_t *)qemu_plugin_insn_data(insn));
+    qemu_plugin_insn_data(insn, &opcode, sizeof(opcode));
 
     for (i = 0; !cnt && i < class_table_sz; i++) {
         class = &class_table[i];
diff --git a/plugins/api.c b/plugins/api.c
index 3912c9cc8f..4e9125ea29 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -216,9 +216,12 @@  qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx)
  * instruction being translated.
  */
 
-const void *qemu_plugin_insn_data(const struct qemu_plugin_insn *insn)
+size_t qemu_plugin_insn_data(const struct qemu_plugin_insn *insn,
+                             void *dest, size_t len)
 {
-    return insn->data->data;
+    len = MIN(len, insn->data->len);
+    memcpy(dest, insn->data->data, len);
+    return len;
 }
 
 size_t qemu_plugin_insn_size(const struct qemu_plugin_insn *insn)