[v2,1/1] plugins: add API to read guest CPU memory from hwaddr

Commit Message

Rowan Hart Aug. 29, 2024, 4:47 p.m. UTC

Signed-off-by: Rowan Hart <[e-mail]>
---
 include/qemu/qemu-plugin.h   | 22 ++++++++++++++++++++++
 plugins/api.c                | 17 +++++++++++++++++
 plugins/qemu-plugins.symbols |  1 +
 3 files changed, 40 insertions(+)

Patch

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index c71c705b69..25f39c0960 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -868,6 +868,28 @@  QEMU_PLUGIN_API
 int qemu_plugin_read_register(struct qemu_plugin_register *handle,
                               GByteArray *buf);
 
+/**
+ * qemu_plugin_read_cpu_memory_hwaddr() - read CPU memory from hwaddr
+ *
+ * @addr: A virtual address to read from
+ * @data: A byte array to store data into
+ * @len: The number of bytes to read, starting from @addr
+ *
+ * @len bytes of data is read starting at @addr and stored into @data. If @data
+ * is not large enough to hold @len bytes, it will be expanded to the necessary
+ * size, reallocating if necessary. @len must be greater than 0.
+ *
+ * This function does not ensure writes are flushed prior to reading, so
+ * callers should take care when calling this function in plugin callbacks to
+ * avoid attempting to read data which may not yet be written and should use
+ * the memory callback API instead.
+ *
+ * Returns true on success and false on failure.
+ */
+QEMU_PLUGIN_API
+bool qemu_plugin_read_cpu_memory_hwaddr(uint64_t addr,
+                                          GByteArray *data, size_t len);
+
 /**
  * qemu_plugin_scoreboard_new() - alloc a new scoreboard
  *
diff --git a/plugins/api.c b/plugins/api.c
index 2ff13d09de..c87bed6641 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -527,6 +527,22 @@  GArray *qemu_plugin_get_registers(void)
     return create_register_handles(regs);
 }
 
+bool qemu_plugin_read_cpu_memory_hwaddr(uint64_t addr,
+                                        GByteArray *data, uint64_t len)
+{
+#ifndef CONFIG_USER_ONLY
+    if (len == 0) {
+        return false;
+    }
+
+    g_byte_array_set_size(data, len);
+    cpu_physical_memory_rw(addr, (void *)data->data, len, 0);
+    return true;
+#else
+    return false;
+#endif
+}
+
 int qemu_plugin_read_register(struct qemu_plugin_register *reg, GByteArray *buf)
 {
     g_assert(current_cpu);
@@ -534,6 +550,7 @@  int qemu_plugin_read_register(struct qemu_plugin_register *reg, GByteArray *buf)
     return gdb_read_register(current_cpu, buf, GPOINTER_TO_INT(reg) - 1);
 }
 
+
 struct qemu_plugin_scoreboard *qemu_plugin_scoreboard_new(size_t element_size)
 {
     return plugin_scoreboard_new(element_size);
diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
index ca773d8d9f..616cae1e7f 100644
--- a/plugins/qemu-plugins.symbols
+++ b/plugins/qemu-plugins.symbols
@@ -20,6 +20,7 @@ 
   qemu_plugin_num_vcpus;
   qemu_plugin_outs;
   qemu_plugin_path_to_binary;
+  qemu_plugin_read_cpu_memory_hwaddr;
   qemu_plugin_read_register;
   qemu_plugin_register_atexit_cb;
   qemu_plugin_register_flush_cb;