plugins: conditional callbacks

Extend plugins API to support callback called with a given criteria
(evaluated inline).

Added functions:
- qemu_plugin_register_vcpu_tb_exec_cond_cb
- qemu_plugin_register_vcpu_insn_exec_cond_cb

They expect as parameter a condition, a qemu_plugin_u64_t (op1) and an
immediate (op2). Callback is called if op1 |cond| op2 is true.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240502211522.346467-6-pierrick.bouvier@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
[AJB: fix re-base conflict with tb_is_mem_only()]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240514174253.694591-8-alex.bennee@linaro.org>

4 files changed, 81 insertions, 0 deletions

diff --git a/plugins/api.c b/plugins/api.c
index b04c5e1..5a0a7f8 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -102,6 +102,25 @@ void qemu_plugin_register_vcpu_tb_exec_cb(struct qemu_plugin_tb *tb,
     }
 }
 
+void qemu_plugin_register_vcpu_tb_exec_cond_cb(struct qemu_plugin_tb *tb,
+                                               qemu_plugin_vcpu_udata_cb_t cb,
+                                               enum qemu_plugin_cb_flags flags,
+                                               enum qemu_plugin_cond cond,
+                                               qemu_plugin_u64 entry,
+                                               uint64_t imm,
+                                               void *udata)
+{
+    if (cond == QEMU_PLUGIN_COND_NEVER || tb_is_mem_only()) {
+        return;
+    }
+    if (cond == QEMU_PLUGIN_COND_ALWAYS) {
+        qemu_plugin_register_vcpu_tb_exec_cb(tb, cb, flags, udata);
+        return;
+    }
+    plugin_register_dyn_cond_cb__udata(&tb->cbs, cb, flags,
+                                       cond, entry, imm, udata);
+}
+
 void qemu_plugin_register_vcpu_tb_exec_inline_per_vcpu(
     struct qemu_plugin_tb *tb,
     enum qemu_plugin_op op,
@@ -123,6 +142,26 @@ void qemu_plugin_register_vcpu_insn_exec_cb(struct qemu_plugin_insn *insn,
     }
 }
 
+void qemu_plugin_register_vcpu_insn_exec_cond_cb(
+    struct qemu_plugin_insn *insn,
+    qemu_plugin_vcpu_udata_cb_t cb,
+    enum qemu_plugin_cb_flags flags,
+    enum qemu_plugin_cond cond,
+    qemu_plugin_u64 entry,
+    uint64_t imm,
+    void *udata)
+{
+    if (cond == QEMU_PLUGIN_COND_NEVER || tb_is_mem_only()) {
+        return;
+    }
+    if (cond == QEMU_PLUGIN_COND_ALWAYS) {
+        qemu_plugin_register_vcpu_insn_exec_cb(insn, cb, flags, udata);
+        return;
+    }
+    plugin_register_dyn_cond_cb__udata(&insn->insn_cbs, cb, flags,
+                                       cond, entry, imm, udata);
+}
+
 void qemu_plugin_register_vcpu_insn_exec_inline_per_vcpu(
     struct qemu_plugin_insn *insn,
     enum qemu_plugin_op op,
diff --git a/plugins/core.c b/plugins/core.c
index 848d482..332474a 100644
--- a/plugins/core.c
+++ b/plugins/core.c
@@ -371,6 +371,38 @@ void plugin_register_dyn_cb__udata(GArray **arr,
     dyn_cb->regular.info = &info[flags];
 }
 
+void plugin_register_dyn_cond_cb__udata(GArray **arr,
+                                        qemu_plugin_vcpu_udata_cb_t cb,
+                                        enum qemu_plugin_cb_flags flags,
+                                        enum qemu_plugin_cond cond,
+                                        qemu_plugin_u64 entry,
+                                        uint64_t imm,
+                                        void *udata)
+{
+    static TCGHelperInfo info[3] = {
+        [QEMU_PLUGIN_CB_NO_REGS].flags = TCG_CALL_NO_RWG,
+        [QEMU_PLUGIN_CB_R_REGS].flags = TCG_CALL_NO_WG,
+        /*
+         * Match qemu_plugin_vcpu_udata_cb_t:
+         *   void (*)(uint32_t, void *)
+         */
+        [0 ... 2].typemask = (dh_typemask(void, 0) |
+                              dh_typemask(i32, 1) |
+                              dh_typemask(ptr, 2))
+    };
+
+    struct qemu_plugin_dyn_cb *dyn_cb = plugin_get_dyn_cb(arr);
+    dyn_cb->userp = udata;
+    dyn_cb->type = PLUGIN_CB_COND;
+    dyn_cb->cond.f.vcpu_udata = cb;
+    dyn_cb->cond.cond = cond;
+    dyn_cb->cond.entry = entry;
+    dyn_cb->cond.imm = imm;
+
+    assert((unsigned)flags < ARRAY_SIZE(info));
+    dyn_cb->cond.info = &info[flags];
+}
+
 void plugin_register_vcpu_mem_cb(GArray **arr,
                                  void *cb,
                                  enum qemu_plugin_cb_flags flags,
diff --git a/plugins/plugin.h b/plugins/plugin.h
index 7c34f23..7d4b4e2 100644
--- a/plugins/plugin.h
+++ b/plugins/plugin.h
@@ -93,6 +93,14 @@ plugin_register_dyn_cb__udata(GArray **arr,
                               qemu_plugin_vcpu_udata_cb_t cb,
                               enum qemu_plugin_cb_flags flags, void *udata);
 
+void
+plugin_register_dyn_cond_cb__udata(GArray **arr,
+                                   qemu_plugin_vcpu_udata_cb_t cb,
+                                   enum qemu_plugin_cb_flags flags,
+                                   enum qemu_plugin_cond cond,
+                                   qemu_plugin_u64 entry,
+                                   uint64_t imm,
+                                   void *udata);
 
 void plugin_register_vcpu_mem_cb(GArray **arr,
                                  void *cb,
diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
index a9fac05..aa0a77a 100644
--- a/plugins/qemu-plugins.symbols
+++ b/plugins/qemu-plugins.symbols
@@ -27,6 +27,7 @@
   qemu_plugin_register_vcpu_idle_cb;
   qemu_plugin_register_vcpu_init_cb;
   qemu_plugin_register_vcpu_insn_exec_cb;
+  qemu_plugin_register_vcpu_insn_exec_cond_cb;
   qemu_plugin_register_vcpu_insn_exec_inline_per_vcpu;
   qemu_plugin_register_vcpu_mem_cb;
   qemu_plugin_register_vcpu_mem_inline_per_vcpu;
@@ -34,6 +35,7 @@
   qemu_plugin_register_vcpu_syscall_cb;
   qemu_plugin_register_vcpu_syscall_ret_cb;
   qemu_plugin_register_vcpu_tb_exec_cb;
+  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_reset;