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* [PATCH] plugins: add two events for cpu_restore_state_from_tb() and cpu_io_recompile()
@ 2024-09-01 16:34 Xingran Wang
  2024-09-02 10:42 ` Alex Bennée
  0 siblings, 1 reply; 8+ messages in thread
From: Xingran Wang @ 2024-09-01 16:34 UTC (permalink / raw)
  To: qemu-devel
  Cc: Xingran Wang, Richard Henderson, Paolo Bonzini, Alex Bennée,
	Alexandre Iooss, Mahmoud Mandour, Pierrick Bouvier

Currently, the instruction count obtained by plugins using the translation
block execution callback is larger than the actual value. Adding callbacks
in cpu_restore_state_from_tb() and cpu_io_recompile() allows plugins to
correct the instruction count when exiting a translation block
mid-execution, properly subtracting the excess unexecuted instructions.

Signed-off-by: Xingran Wang <wangxingran123456@outlook.com>
---
 accel/tcg/translate-all.c    |  27 ++++++++
 include/qemu/plugin-event.h  |   2 +
 include/qemu/plugin.h        |  24 +++++++
 include/qemu/qemu-plugin.h   | 131 +++++++++++++++++++++++++++++++++++
 plugins/api.c                |  78 +++++++++++++++++++++
 plugins/core.c               |  42 +++++++++++
 plugins/qemu-plugins.symbols |  10 +++
 tests/tcg/plugins/bb.c       |  25 +++++++
 8 files changed, 339 insertions(+)

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index fdf6d8ac19..642f684372 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -65,6 +65,7 @@
 #include "internal-target.h"
 #include "tcg/perf.h"
 #include "tcg/insn-start-words.h"
+#include "qemu/plugin.h"
 
 TBContext tb_ctx;
 
@@ -218,6 +219,19 @@ void cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
         cpu->neg.icount_decr.u16.low += insns_left;
     }
 
+#ifdef CONFIG_PLUGIN
+    /*
+     * Notify the plugin with the relevant information
+     * when restoring the execution state of a TB.
+     */
+    struct qemu_plugin_tb_restore ptb_restore;
+    ptb_restore.cpu_index = cpu->cpu_index;
+    ptb_restore.insns_left = insns_left;
+    ptb_restore.tb_n = tb->icount;
+    ptb_restore.tb_pc = tb->pc;
+    qemu_plugin_tb_restore_cb(cpu, &ptb_restore);
+#endif
+
     cpu->cc->tcg_ops->restore_state_to_opc(cpu, tb, data);
 }
 
@@ -641,6 +655,19 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
         }
     }
 
+#ifdef CONFIG_PLUGIN
+    /*
+     * Notify the plugin with the relevant information
+     * when cpu_io_recompile is triggered.
+     */
+    struct qemu_plugin_tb_recompile_io ptb_recompile_io;
+    ptb_recompile_io.cpu_index = cpu->cpu_index;
+    ptb_recompile_io.next_tb_n = n;
+    ptb_recompile_io.tb_pc = tb->pc;
+    ptb_recompile_io.cpu_pc = cpu->cc->get_pc(cpu);
+    qemu_plugin_tb_recompile_io_cb(cpu, &ptb_recompile_io);
+#endif
+
     cpu_loop_exit_noexc(cpu);
 }
 
diff --git a/include/qemu/plugin-event.h b/include/qemu/plugin-event.h
index 7056d8427b..875e2b6071 100644
--- a/include/qemu/plugin-event.h
+++ b/include/qemu/plugin-event.h
@@ -14,6 +14,8 @@ enum qemu_plugin_event {
     QEMU_PLUGIN_EV_VCPU_INIT,
     QEMU_PLUGIN_EV_VCPU_EXIT,
     QEMU_PLUGIN_EV_VCPU_TB_TRANS,
+    QEMU_PLUGIN_EV_VCPU_TB_RESTORE,
+    QEMU_PLUGIN_EV_VCPU_TB_RECOMPILE_IO,
     QEMU_PLUGIN_EV_VCPU_IDLE,
     QEMU_PLUGIN_EV_VCPU_RESUME,
     QEMU_PLUGIN_EV_VCPU_SYSCALL,
diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
index af5f9db469..9250932e44 100644
--- a/include/qemu/plugin.h
+++ b/include/qemu/plugin.h
@@ -60,6 +60,8 @@ union qemu_plugin_cb_sig {
     qemu_plugin_vcpu_simple_cb_t     vcpu_simple;
     qemu_plugin_vcpu_udata_cb_t      vcpu_udata;
     qemu_plugin_vcpu_tb_trans_cb_t   vcpu_tb_trans;
+    qemu_plugin_vcpu_tb_restore_cb_t   vcpu_tb_restore;
+    qemu_plugin_vcpu_tb_recompile_io_cb_t   vcpu_tb_recompile_io;
     qemu_plugin_vcpu_mem_cb_t        vcpu_mem;
     qemu_plugin_vcpu_syscall_cb_t    vcpu_syscall;
     qemu_plugin_vcpu_syscall_ret_cb_t vcpu_syscall_ret;
@@ -139,6 +141,22 @@ struct qemu_plugin_tb {
     GArray *cbs;
 };
 
+/* TranslationBlock Restore info */
+struct qemu_plugin_tb_restore {
+    unsigned int cpu_index;
+    int insns_left;
+    size_t tb_n;
+    uint64_t tb_pc;
+};
+
+/* TranslationBlock Recompile IO info */
+struct qemu_plugin_tb_recompile_io {
+    unsigned int cpu_index;
+    uint32_t next_tb_n;
+    uint64_t tb_pc;
+    uint64_t cpu_pc;
+};
+
 /**
  * struct CPUPluginState - per-CPU state for plugins
  * @event_mask: plugin event bitmap. Modified only via async work.
@@ -158,6 +176,12 @@ CPUPluginState *qemu_plugin_create_vcpu_state(void);
 void qemu_plugin_vcpu_init_hook(CPUState *cpu);
 void qemu_plugin_vcpu_exit_hook(CPUState *cpu);
 void qemu_plugin_tb_trans_cb(CPUState *cpu, struct qemu_plugin_tb *tb);
+void
+qemu_plugin_tb_restore_cb(CPUState *cpu,
+                          struct qemu_plugin_tb_restore *tb);
+void
+qemu_plugin_tb_recompile_io_cb(CPUState *cpu,
+                               struct qemu_plugin_tb_recompile_io *tb);
 void qemu_plugin_vcpu_idle_cb(CPUState *cpu);
 void qemu_plugin_vcpu_resume_cb(CPUState *cpu);
 void
diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index c71c705b69..e879175b23 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -228,6 +228,10 @@ struct qemu_plugin_tb;
 struct qemu_plugin_insn;
 /** struct qemu_plugin_scoreboard - Opaque handle for a scoreboard */
 struct qemu_plugin_scoreboard;
+/** struct qemu_plugin_tb_restore - Opaque handle for TB restore */
+struct qemu_plugin_tb_restore;
+/** struct qemu_plugin_tb_recompile_io - Opaque handle for recompile_io */
+struct qemu_plugin_tb_recompile_io;
 
 /**
  * typedef qemu_plugin_u64 - uint64_t member of an entry in a scoreboard
@@ -293,6 +297,22 @@ enum qemu_plugin_cond {
 typedef void (*qemu_plugin_vcpu_tb_trans_cb_t)(qemu_plugin_id_t id,
                                                struct qemu_plugin_tb *tb);
 
+/**
+ * typedef qemu_plugin_vcpu_tb_restore_cb_t - cpu restore state from TB callback
+ * @id: unique plugin id
+ * @tb_restore: opaque handle used for querying TB restore info.
+ */
+typedef void (*qemu_plugin_vcpu_tb_restore_cb_t)(qemu_plugin_id_t id,
+    struct qemu_plugin_tb_restore *tb_restore);
+
+/**
+ * typedef qemu_plugin_vcpu_tb_restore_cb_t - cpu io recompile callback
+ * @id: unique plugin id
+ * @tb_restore: opaque handle used for querying cpu io recompile info.
+ */
+typedef void (*qemu_plugin_vcpu_tb_recompile_io_cb_t)(qemu_plugin_id_t id,
+    struct qemu_plugin_tb_recompile_io *tb_recompile_io);
+
 /**
  * qemu_plugin_register_vcpu_tb_trans_cb() - register a translate cb
  * @id: plugin ID
@@ -309,6 +329,33 @@ QEMU_PLUGIN_API
 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_restore_cb() - register a TB restore cb
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a TB restore occurs. The @cb
+ * function is passed an opaque qemu_plugin_type which it can query
+ * for additional information.
+ */
+QEMU_PLUGIN_API
+void qemu_plugin_register_vcpu_tb_restore_cb(qemu_plugin_id_t id,
+    qemu_plugin_vcpu_tb_restore_cb_t cb);
+
+/**
+ * qemu_plugin_register_vcpu_tb_recompile_io_cb()
+ * register a cpu io recompile cb
+ * @id: plugin ID
+ * @cb: callback function
+ *
+ * The @cb function is called every time a cpu io recompile occurs. The @cb
+ * function is passed an opaque qemu_plugin_type which it can query
+ * for additional information.
+ */
+QEMU_PLUGIN_API
+void qemu_plugin_register_vcpu_tb_recompile_io_cb(qemu_plugin_id_t id,
+    qemu_plugin_vcpu_tb_recompile_io_cb_t cb);
+
 /**
  * qemu_plugin_register_vcpu_tb_exec_cb() - register execution callback
  * @tb: the opaque qemu_plugin_tb handle for the translation
@@ -469,6 +516,90 @@ QEMU_PLUGIN_API
 struct qemu_plugin_insn *
 qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx);
 
+/**
+ * qemu_plugin_tb_restore_cpu_index()
+ * query helper for cpu index where TB restore occurs
+ * @tb_restore: Opaque handle to the TB restore structure passed to the callback
+ *
+ * Returns: cpu index where the TB restore occurs.
+ */
+QEMU_PLUGIN_API
+unsigned int qemu_plugin_tb_restore_cpu_index(
+    const struct qemu_plugin_tb_restore *tb_restore);
+
+/**
+ * qemu_plugin_tb_restore_insns_left()
+ * query helper for number of unexecuted instructions in TB
+ * @tb_restore: Opaque handle to the TB restore structure passed to the callback
+ *
+ * Returns: number of unexecuted instructions in this block.
+ */
+QEMU_PLUGIN_API
+int qemu_plugin_tb_restore_insns_left(
+    const struct qemu_plugin_tb_restore *tb_restore);
+
+/**
+ * qemu_plugin_tb_restore_tb_n() - query helper for number of insns in TB
+ * @tb_restore: Opaque handle to the TB restore structure passed to the callback
+ *
+ * Returns: number of instructions in this block.
+ */
+QEMU_PLUGIN_API
+size_t qemu_plugin_tb_restore_tb_n(
+    const struct qemu_plugin_tb_restore *tb_restore);
+
+/**
+ * qemu_plugin_tb_restore_tb_pc() - query helper for vaddr of TB start
+ * @tb_restore: Opaque handle to the TB restore structure passed to the callback
+ *
+ * Returns: virtual address of block start.
+ */
+QEMU_PLUGIN_API
+uint64_t qemu_plugin_tb_restore_tb_pc(
+    const struct qemu_plugin_tb_restore *tb_restore);
+
+/**
+ * qemu_plugin_tb_recompile_io_cpu_index()
+ * query helper for cpu index where recompile I/O occurs
+ * @tb_recompile_io: Opaque handle to the TB recompile I/O structure
+ *
+ * Returns: cpu index where I/O recompile occurs.
+ */
+QEMU_PLUGIN_API
+unsigned int qemu_plugin_tb_recompile_io_cpu_index(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io);
+
+/**
+ * qemu_plugin_tb_recompile_io_next_tb_n()
+ * query helper for number of insns in next TB
+ * @tb_recompile_io: Opaque handle to the TB recompile I/O structure
+ *
+ * Returns: number of instructions in next block.
+ */
+QEMU_PLUGIN_API
+uint32_t qemu_plugin_tb_recompile_io_next_tb_n(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io);
+
+/**
+ * qemu_plugin_tb_recompile_io_tb_pc() - query helper for vaddr of TB start
+ * @tb_recompile_io: Opaque handle to the TB recompile I/O structure
+ *
+ * Returns: virtual address of block start.
+ */
+QEMU_PLUGIN_API
+uint64_t qemu_plugin_tb_recompile_io_tb_pc(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io);
+
+/**
+ * qemu_plugin_tb_recompile_io_cpu_pc() - query helper for cpu program counter
+ * @tb_recompile_io: Opaque handle to the TB recompile I/O structure
+ *
+ * Returns: program counter of cpu where recompile I/O occurs.
+ */
+QEMU_PLUGIN_API
+uint64_t qemu_plugin_tb_recompile_io_cpu_pc(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io);
+
 /**
  * qemu_plugin_insn_data() - copy instruction data
  * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
diff --git a/plugins/api.c b/plugins/api.c
index 2ff13d09de..50aee3b38c 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -206,6 +206,18 @@ void qemu_plugin_register_vcpu_tb_trans_cb(qemu_plugin_id_t id,
     plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_TB_TRANS, cb);
 }
 
+void qemu_plugin_register_vcpu_tb_restore_cb(qemu_plugin_id_t id,
+    qemu_plugin_vcpu_tb_restore_cb_t cb)
+{
+    plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_TB_RESTORE, cb);
+}
+
+void qemu_plugin_register_vcpu_tb_recompile_io_cb(qemu_plugin_id_t id,
+    qemu_plugin_vcpu_tb_recompile_io_cb_t cb)
+{
+    plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_TB_RECOMPILE_IO, cb);
+}
+
 void qemu_plugin_register_vcpu_syscall_cb(qemu_plugin_id_t id,
                                           qemu_plugin_vcpu_syscall_cb_t cb)
 {
@@ -257,6 +269,72 @@ qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx)
     return insn;
 }
 
+/*
+ * CPU restore state from TB information:
+ *
+ * A plugin can query various details about the TB being restored,
+ * including the CPU index, the number of remaining instructions to execute,
+ * the total number of instructions, and the virtual address of
+ * the start of the block.
+ */
+
+unsigned int qemu_plugin_tb_restore_cpu_index(
+    const struct qemu_plugin_tb_restore *tb_restore)
+{
+    return tb_restore->cpu_index;
+}
+
+int qemu_plugin_tb_restore_insns_left(
+    const struct qemu_plugin_tb_restore *tb_restore)
+{
+    return tb_restore->insns_left;
+}
+
+size_t qemu_plugin_tb_restore_tb_n(
+    const struct qemu_plugin_tb_restore *tb_restore)
+{
+    return tb_restore->tb_n;
+}
+
+uint64_t qemu_plugin_tb_restore_tb_pc(
+    const struct qemu_plugin_tb_restore *tb_restore)
+{
+    return tb_restore->tb_pc;
+}
+
+/*
+ * CPU Recompile I/O information:
+ *
+ * A plugin can query various details related to the I/O recompile process,
+ * including the CPU index, the number of instructions in next TB,
+ * the virtual address of the start of current block, and the program counter
+ * of the CPU at the time of the recompile.
+ */
+
+unsigned int qemu_plugin_tb_recompile_io_cpu_index(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io)
+{
+    return tb_recompile_io->cpu_index;
+}
+
+uint32_t qemu_plugin_tb_recompile_io_next_tb_n(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io)
+{
+    return tb_recompile_io->next_tb_n;
+}
+
+uint64_t qemu_plugin_tb_recompile_io_tb_pc(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io)
+{
+    return tb_recompile_io->tb_pc;
+}
+
+uint64_t qemu_plugin_tb_recompile_io_cpu_pc(
+    const struct qemu_plugin_tb_recompile_io *tb_recompile_io)
+{
+    return tb_recompile_io->cpu_pc;
+}
+
 /*
  * Instruction information
  *
diff --git a/plugins/core.c b/plugins/core.c
index 2897453cac..a4f429b5f2 100644
--- a/plugins/core.c
+++ b/plugins/core.c
@@ -485,6 +485,48 @@ void qemu_plugin_tb_trans_cb(CPUState *cpu, struct qemu_plugin_tb *tb)
     }
 }
 
+/*
+ * Disable CFI checks.
+ * The callback function has been loaded from an external library so we do not
+ * have type information
+ */
+QEMU_DISABLE_CFI
+void qemu_plugin_tb_restore_cb(CPUState *cpu,
+                               struct qemu_plugin_tb_restore *tb_restore)
+{
+    struct qemu_plugin_cb *cb, *next;
+    enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_TB_RESTORE;
+
+    /* no plugin_state->event_mask check here; caller should have checked */
+
+    QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
+        qemu_plugin_vcpu_tb_restore_cb_t func = cb->f.vcpu_tb_restore;
+
+        func(cb->ctx->id, tb_restore);
+    }
+}
+
+/*
+ * Disable CFI checks.
+ * The callback function has been loaded from an external library so we do not
+ * have type information
+ */
+QEMU_DISABLE_CFI
+void qemu_plugin_tb_recompile_io_cb(CPUState *cpu,
+    struct qemu_plugin_tb_recompile_io *tb_recompile_io)
+{
+    struct qemu_plugin_cb *cb, *next;
+    enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_TB_RECOMPILE_IO;
+
+    /* no plugin_state->event_mask check here; caller should have checked */
+
+    QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
+        qemu_plugin_vcpu_tb_recompile_io_cb_t func = cb->f.vcpu_tb_recompile_io;
+
+        func(cb->ctx->id, tb_recompile_io);
+    }
+}
+
 /*
  * Disable CFI checks.
  * The callback function has been loaded from an external library so we do not
diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
index ca773d8d9f..7dcd9f76d5 100644
--- a/plugins/qemu-plugins.symbols
+++ b/plugins/qemu-plugins.symbols
@@ -38,6 +38,8 @@
   qemu_plugin_register_vcpu_tb_exec_cond_cb;
   qemu_plugin_register_vcpu_tb_exec_inline_per_vcpu;
   qemu_plugin_register_vcpu_tb_trans_cb;
+  qemu_plugin_register_vcpu_tb_restore_cb;
+  qemu_plugin_register_vcpu_tb_recompile_io_cb;
   qemu_plugin_request_time_control;
   qemu_plugin_reset;
   qemu_plugin_scoreboard_free;
@@ -47,6 +49,14 @@
   qemu_plugin_tb_get_insn;
   qemu_plugin_tb_n_insns;
   qemu_plugin_tb_vaddr;
+  qemu_plugin_tb_restore_cpu_index;
+  qemu_plugin_tb_restore_insns_left;
+  qemu_plugin_tb_restore_tb_n;
+  qemu_plugin_tb_restore_tb_pc;
+  qemu_plugin_tb_recompile_io_cpu_index;
+  qemu_plugin_tb_recompile_io_next_tb_n;
+  qemu_plugin_tb_recompile_io_tb_pc;
+  qemu_plugin_tb_recompile_io_cpu_pc;
   qemu_plugin_u64_add;
   qemu_plugin_u64_get;
   qemu_plugin_u64_set;
diff --git a/tests/tcg/plugins/bb.c b/tests/tcg/plugins/bb.c
index 36776dee1e..18a16e885f 100644
--- a/tests/tcg/plugins/bb.c
+++ b/tests/tcg/plugins/bb.c
@@ -93,6 +93,29 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
     }
 }
 
+static void vcpu_tb_restore(qemu_plugin_id_t id,
+                            struct qemu_plugin_tb_restore *tb_restore)
+{
+    unsigned int cpu_index;
+    cpu_index = qemu_plugin_tb_restore_cpu_index(tb_restore);
+    CPUCount *count = qemu_plugin_scoreboard_find(counts, cpu_index);
+
+    size_t insns_left = qemu_plugin_tb_restore_insns_left(tb_restore);
+    count->insn_count -= insns_left;
+}
+
+static void vcpu_tb_recompile_io(qemu_plugin_id_t id,
+    struct qemu_plugin_tb_recompile_io *tb_recompile_io)
+{
+    unsigned int cpu_index;
+    cpu_index = qemu_plugin_tb_recompile_io_cpu_index(tb_recompile_io);
+    CPUCount *count = qemu_plugin_scoreboard_find(counts, cpu_index);
+
+    uint32_t next_tb_n = qemu_plugin_tb_recompile_io_next_tb_n(tb_recompile_io);
+    count->insn_count += next_tb_n;
+}
+
+
 QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
                                            const qemu_info_t *info,
                                            int argc, char **argv)
@@ -128,6 +151,8 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
     }
 
     qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
+    qemu_plugin_register_vcpu_tb_restore_cb(id, vcpu_tb_restore);
+    qemu_plugin_register_vcpu_tb_recompile_io_cb(id, vcpu_tb_recompile_io);
     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
     return 0;
 }
-- 
2.34.1



^ permalink raw reply related	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2024-09-03 17:18 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-09-01 16:34 [PATCH] plugins: add two events for cpu_restore_state_from_tb() and cpu_io_recompile() Xingran Wang
2024-09-02 10:42 ` Alex Bennée
2024-09-02 16:08   ` Pierrick Bouvier
2024-09-02 17:52     ` Alex Bennée
2024-09-02 18:56       ` Pierrick Bouvier
2024-09-03  6:53         ` Xingran Wang
2024-09-03 16:41       ` Richard Henderson
2024-09-03 17:17         ` Alex Bennée

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