[Qemu-devel] [PATCH v4 13/54] plugin: add user-facing API

["Alex Bennée" <alex.bennee@linaro.org>]

From: "Emilio G. Cota" <cota@braap.org>

Add the API first to ease review.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v3
  - merge in changes to plugin install/reset/uninstall
  - split api file
v4
  - s/is/it/
  - more docstrings
  - remove qemu_plugin_register_vcpu_mem_haddr_cb and related bits
  - add qemu_plugin_get_hwaddr and related bits
  - drop vcpu_index from tb_trans_cb_t
---
 include/qemu/qemu-plugin.h | 351 +++++++++++++++++++++++++++++++++++++
 1 file changed, 351 insertions(+)
 create mode 100644 include/qemu/qemu-plugin.h

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
new file mode 100644
index 00000000000..d9c1ca3b4cf
--- /dev/null
+++ b/include/qemu/qemu-plugin.h
@@ -0,0 +1,351 @@
+/*
+ * Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
+ * Copyright (C) 2019, Linaro
+ *
+ * License: GNU GPL, version 2 or later.
+ *   See the COPYING file in the top-level directory.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef QEMU_PLUGIN_API_H
+#define QEMU_PLUGIN_API_H
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+/*
+ * For best performance, build the plugin with -fvisibility=hidden so that
+ * QEMU_PLUGIN_LOCAL is implicit. Then, just mark qemu_plugin_install with
+ * QEMU_PLUGIN_EXPORT. For more info, see
+ *   https://gcc.gnu.org/wiki/Visibility
+ */
+#if defined _WIN32 || defined __CYGWIN__
+  #ifdef BUILDING_DLL
+    #define QEMU_PLUGIN_EXPORT __declspec(dllexport)
+  #else
+    #define QEMU_PLUGIN_EXPORT __declspec(dllimport)
+  #endif
+  #define QEMU_PLUGIN_LOCAL
+#else
+  #if __GNUC__ >= 4
+    #define QEMU_PLUGIN_EXPORT __attribute__((visibility("default")))
+    #define QEMU_PLUGIN_LOCAL  __attribute__((visibility("hidden")))
+  #else
+    #define QEMU_PLUGIN_EXPORT
+    #define QEMU_PLUGIN_LOCAL
+  #endif
+#endif
+
+typedef uint64_t qemu_plugin_id_t;
+
+/**
+ * qemu_plugin_install() - Install a plugin
+ * @id: this plugin's opaque ID
+ * @argc: number of arguments
+ * @argv: array of arguments (@argc elements)
+ *
+ * All plugins must export this symbol.
+ *
+ * Note: Calling qemu_plugin_uninstall() from this function is a bug. To raise
+ * an error during install, return !0.
+ *
+ * Note: @argv remains valid throughout the lifetime of the loaded plugin.
+ */
+QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id, int argc,
+                                           char **argv);
+
+/*
+ * Prototypes for the various callback styles we will be registering
+ * in the following functions.
+ */
+typedef void (*qemu_plugin_simple_cb_t)(qemu_plugin_id_t id);
+
+typedef void (*qemu_plugin_udata_cb_t)(qemu_plugin_id_t id, void *userdata);
+
+typedef void (*qemu_plugin_vcpu_simple_cb_t)(qemu_plugin_id_t id,
+                                             unsigned int vcpu_index);
+
+typedef void (*qemu_plugin_vcpu_udata_cb_t)(unsigned int vcpu_index,
+                                            void *userdata);
+
+/**
+ * qemu_plugin_uninstall() - Uninstall a plugin
+ * @id: this plugin's opaque ID
+ * @cb: callback to be called once the plugin has been removed
+ *
+ * Do NOT assume that the plugin has been uninstalled once this function
+ * returns. Plugins are uninstalled asynchronously, and therefore the given
+ * plugin receives callbacks until @cb is called.
+ *
+ * Note: Calling this function from qemu_plugin_install() is a bug.
+ */
+void qemu_plugin_uninstall(qemu_plugin_id_t id, qemu_plugin_simple_cb_t cb);
+
+/**
+ * qemu_plugin_reset() - Reset a plugin
+ * @id: this plugin's opaque ID
+ * @cb: callback to be called once the plugin has been reset
+ *
+ * Unregisters all callbacks for the plugin given by @id.
+ *
+ * Do NOT assume that the plugin has been reset once this function returns.
+ * Plugins are reset asynchronously, and therefore the given plugin receives
+ * callbacks until @cb is called.
+ */
+void qemu_plugin_reset(qemu_plugin_id_t id, qemu_plugin_simple_cb_t cb);
+
+/**
+ * qemu_plugin_register_vcpu_init_cb() - register a vCPU initialization callback
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a vCPU is initialized.
+ *
+ * See also: qemu_plugin_register_vcpu_exit_cb()
+ */
+void qemu_plugin_register_vcpu_init_cb(qemu_plugin_id_t id,
+                                       qemu_plugin_vcpu_simple_cb_t cb);
+
+/**
+ * qemu_plugin_register_vcpu_exit_cb() - register a vCPU exit callback
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a vCPU exits.
+ *
+ * See also: qemu_plugin_register_vcpu_init_cb()
+ */
+void qemu_plugin_register_vcpu_exit_cb(qemu_plugin_id_t id,
+                                       qemu_plugin_vcpu_simple_cb_t cb);
+
+/**
+ * qemu_plugin_register_vcpu_idle_cb() - register a vCPU idle callback
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a vCPU idles.
+ */
+void qemu_plugin_register_vcpu_idle_cb(qemu_plugin_id_t id,
+                                       qemu_plugin_vcpu_simple_cb_t cb);
+
+/**
+ * qemu_plugin_register_vcpu_resume_cb() - register a vCPU resume callback
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a vCPU resumes execution.
+ */
+void qemu_plugin_register_vcpu_resume_cb(qemu_plugin_id_t id,
+                                         qemu_plugin_vcpu_simple_cb_t cb);
+
+/*
+ * Opaque types that the plugin is given during the translation and
+ * instrumentation phase.
+ */
+struct qemu_plugin_tb;
+struct qemu_plugin_insn;
+
+enum qemu_plugin_cb_flags {
+    QEMU_PLUGIN_CB_NO_REGS, /* callback does not access the CPU's regs */
+    QEMU_PLUGIN_CB_R_REGS,  /* callback reads the CPU's regs */
+    QEMU_PLUGIN_CB_RW_REGS, /* callback reads and writes the CPU's regs */
+};
+
+enum qemu_plugin_mem_rw {
+    QEMU_PLUGIN_MEM_R = 1,
+    QEMU_PLUGIN_MEM_W,
+    QEMU_PLUGIN_MEM_RW,
+};
+
+/**
+ * qemu_plugin_register_vcpu_tb_trans_cb() - register a translate cb
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a translation occurs. The @cb
+ * function is passed an opaque qemu_plugin_type which it can query
+ * for additional information including the list of translated
+ * instructions. At this point the plugin can register further
+ * callbacks to be triggered when the block or individual instruction
+ * executes.
+ */
+typedef void (*qemu_plugin_vcpu_tb_trans_cb_t)(qemu_plugin_id_t id,
+                                               struct qemu_plugin_tb *tb);
+
+void qemu_plugin_register_vcpu_tb_trans_cb(qemu_plugin_id_t id,
+                                           qemu_plugin_vcpu_tb_trans_cb_t cb);
+
+/**
+ * qemu_plugin_register_vcpu_tb_trans_exec_cb() - register execution callback
+ * @tb: the opaque qemu_plugin_tb handle for the translation
+ * @cb: callback function
+ * @flags: does the plugin read or write the CPU's registers?
+ * @userdata: any plugin data to pass to the @cb?
+ *
+ * The @cb function is called every time a translated unit executes.
+ */
+void qemu_plugin_register_vcpu_tb_exec_cb(struct qemu_plugin_tb *tb,
+                                          qemu_plugin_vcpu_udata_cb_t cb,
+                                          enum qemu_plugin_cb_flags flags,
+                                          void *userdata);
+
+enum qemu_plugin_op {
+    QEMU_PLUGIN_INLINE_ADD_U64,
+};
+
+/**
+ * qemu_plugin_register_vcpu_tb_trans_exec_inline() - execution inline op
+ * @tb: the opaque qemu_plugin_tb handle for the translation
+ * @op: the type of qemu_plugin_op (e.g. ADD_U64)
+ * @ptr: the target memory location for the op
+ * @imm: the op data (e.g. 1)
+ *
+ * Insert an inline op to every time a translated unit executes.
+ * Useful if you just want to increment a single counter somewhere in
+ * memory.
+ */
+void qemu_plugin_register_vcpu_tb_exec_inline(struct qemu_plugin_tb *tb,
+                                              enum qemu_plugin_op op,
+                                              void *ptr, uint64_t imm);
+
+/**
+ * qemu_plugin_register_vcpu_insn_exec_cb() - register insn execution cb
+ * @insn: the opaque qemu_plugin_insn handle for an instruction
+ * @cb: callback function
+ * @flags: does the plugin read or write the CPU's registers?
+ * @userdata: any plugin data to pass to the @cb?
+ *
+ * The @cb function is called every time an instruction is executed
+ */
+void qemu_plugin_register_vcpu_insn_exec_cb(struct qemu_plugin_insn *insn,
+                                            qemu_plugin_vcpu_udata_cb_t cb,
+                                            enum qemu_plugin_cb_flags flags,
+                                            void *userdata);
+
+/**
+ * qemu_plugin_register_vcpu_insn_exec_inline() - insn execution inline op
+ * @insn: the opaque qemu_plugin_insn handle for an instruction
+ * @cb: callback function
+ * @op: the type of qemu_plugin_op (e.g. ADD_U64)
+ * @ptr: the target memory location for the op
+ * @imm: the op data (e.g. 1)
+ *
+ * Insert an inline op to every time an instruction executes. Useful
+ * if you just want to increment a single counter somewhere in memory.
+ */
+void qemu_plugin_register_vcpu_insn_exec_inline(struct qemu_plugin_insn *insn,
+                                                enum qemu_plugin_op op,
+                                                void *ptr, uint64_t imm);
+
+/*
+ * Helpers to query information about the instructions in a block
+ */
+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);
+
+struct qemu_plugin_insn *
+qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx);
+
+const void *qemu_plugin_insn_data(const struct qemu_plugin_insn *insn);
+
+size_t qemu_plugin_insn_size(const struct qemu_plugin_insn *insn);
+
+uint64_t qemu_plugin_insn_vaddr(const struct qemu_plugin_insn *insn);
+void *qemu_plugin_insn_haddr(const struct qemu_plugin_insn *insn);
+
+/*
+ * Memory Instrumentation
+ *
+ * The anonymous qemu_plugin_meminfo_t and qemu_plugin_hwaddr types
+ * can be used in queries to QEMU to get more information about a
+ * given memory access.
+ */
+typedef uint32_t qemu_plugin_meminfo_t;
+struct qemu_plugin_hwaddr;
+
+/* meminfo queries */
+unsigned int qemu_plugin_mem_size_shift(qemu_plugin_meminfo_t info);
+bool qemu_plugin_mem_is_sign_extended(qemu_plugin_meminfo_t info);
+bool qemu_plugin_mem_is_big_endian(qemu_plugin_meminfo_t info);
+bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info);
+
+/*
+ * qemu_plugin_get_hwaddr():
+ * @vaddr: the virtual address of the memory operation
+ *
+ * For system emulation returns a qemu_plugin_hwaddr handle to query
+ * details about the actual physical address backing the virtual
+ * address. For linux-user guests it just returns NULL.
+ *
+ * This handle is *only* valid for the duration of the callback. Any
+ * information about the handle should be recovered before the
+ * callback returns.
+ */
+struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
+                                                  uint64_t vaddr);
+
+bool qemu_plugin_hwaddr_is_io(struct qemu_plugin_hwaddr *hwaddr);
+uint64_t qemu_plugin_hwaddr_to_raddr(const struct qemu_plugin_hwaddr *haddr);
+
+typedef void
+(*qemu_plugin_vcpu_mem_cb_t)(unsigned int vcpu_index,
+                             qemu_plugin_meminfo_t info, uint64_t vaddr,
+                             void *userdata);
+
+void qemu_plugin_register_vcpu_mem_cb(struct qemu_plugin_insn *insn,
+                                      qemu_plugin_vcpu_mem_cb_t cb,
+                                      enum qemu_plugin_cb_flags flags,
+                                      enum qemu_plugin_mem_rw rw,
+                                      void *userdata);
+
+void qemu_plugin_register_vcpu_mem_inline(struct qemu_plugin_insn *insn,
+                                          enum qemu_plugin_mem_rw rw,
+                                          enum qemu_plugin_op op, void *ptr,
+                                          uint64_t imm);
+
+
+
+typedef void
+(*qemu_plugin_vcpu_syscall_cb_t)(qemu_plugin_id_t id, unsigned int vcpu_index,
+                                 int64_t num, uint64_t a1, uint64_t a2,
+                                 uint64_t a3, uint64_t a4, uint64_t a5,
+                                 uint64_t a6, uint64_t a7, uint64_t a8);
+
+void qemu_plugin_register_vcpu_syscall_cb(qemu_plugin_id_t id,
+                                          qemu_plugin_vcpu_syscall_cb_t cb);
+
+typedef void
+(*qemu_plugin_vcpu_syscall_ret_cb_t)(qemu_plugin_id_t id, unsigned int vcpu_idx,
+                                     int64_t num, int64_t ret);
+
+void
+qemu_plugin_register_vcpu_syscall_ret_cb(qemu_plugin_id_t id,
+                                         qemu_plugin_vcpu_syscall_ret_cb_t cb);
+
+
+/**
+ * qemu_plugin_vcpu_for_each() - iterate over the existing vCPU
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called once for each existing vCPU.
+ *
+ * See also: qemu_plugin_register_vcpu_init_cb()
+ */
+void qemu_plugin_vcpu_for_each(qemu_plugin_id_t id,
+                               qemu_plugin_vcpu_simple_cb_t cb);
+
+void qemu_plugin_register_flush_cb(qemu_plugin_id_t id,
+                                   qemu_plugin_simple_cb_t cb);
+
+void qemu_plugin_register_atexit_cb(qemu_plugin_id_t id,
+                                    qemu_plugin_udata_cb_t cb, void *userdata);
+
+/* returns -1 in user-mode */
+int qemu_plugin_n_vcpus(void);
+
+/* returns -1 in user-mode */
+int qemu_plugin_n_max_vcpus(void);
+
+#endif /* QEMU_PLUGIN_API_H */
-- 
2.20.1