plugins: create CPUPluginState and migrate plugin_mask

As we expand the per-vCPU data for plugins we don't want to pollute
CPUState. For now this just moves the plugin_mask (renamed to
event_mask) as the memory callbacks are accessed directly by TCG
generated code.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240227144335.1196131-23-alex.bennee@linaro.org>

accel/tcg/plugin-gen.c

@@ -43,6 +43,7 @@
  * CPU's index into a TCG temp, since the first callback did it already.
  */
 #include "qemu/osdep.h"
+#include "qemu/plugin.h"
 #include "cpu.h"
 #include "tcg/tcg.h"
 #include "tcg/tcg-temp-internal.h"
@@ -831,7 +832,7 @@ bool plugin_gen_tb_start(CPUState *cpu, const DisasContextBase *db,
 {
     bool ret = false;
 
-    if (test_bit(QEMU_PLUGIN_EV_VCPU_TB_TRANS, cpu->plugin_mask)) {
+    if (test_bit(QEMU_PLUGIN_EV_VCPU_TB_TRANS, cpu->plugin_state->event_mask)) {
         struct qemu_plugin_tb *ptb = tcg_ctx->plugin_tb;
         int i;
 

hw/core/cpu-common.c

@@ -194,10 +194,12 @@ static void cpu_common_parse_features(const char *typename, char *features,
     }
 }
 
+#ifdef CONFIG_PLUGIN
 static void qemu_plugin_vcpu_init__async(CPUState *cpu, run_on_cpu_data unused)
 {
     qemu_plugin_vcpu_init_hook(cpu);
 }
+#endif
 
 static void cpu_common_realizefn(DeviceState *dev, Error **errp)
 {
@@ -223,9 +225,12 @@ static void cpu_common_realizefn(DeviceState *dev, Error **errp)
     }
 
     /* Plugin initialization must wait until the cpu start executing code */
+#ifdef CONFIG_PLUGIN
     if (tcg_enabled()) {
+        cpu->plugin_state = qemu_plugin_create_vcpu_state();
         async_run_on_cpu(cpu, qemu_plugin_vcpu_init__async, RUN_ON_CPU_NULL);
     }
+#endif
 
     /* NOTE: latest generic point where the cpu is fully realized */
 }

include/hw/core/cpu.h

@@ -31,7 +31,6 @@
 #include "qemu/rcu_queue.h"
 #include "qemu/queue.h"
 #include "qemu/thread.h"
-#include "qemu/plugin-event.h"
 #include "qom/object.h"
 
 typedef int (*WriteCoreDumpFunction)(const void *buf, size_t size,
@@ -434,7 +433,8 @@ struct qemu_work_item;
  * @kvm_fd: vCPU file descriptor for KVM.
  * @work_mutex: Lock to prevent multiple access to @work_list.
  * @work_list: List of pending asynchronous work.
- * @plugin_mask: Plugin event bitmap. Modified only via async work.
+ * @plugin_mem_cbs: active plugin memory callbacks
+ * @plugin_state: per-CPU plugin state
  * @ignore_memory_transaction_failures: Cached copy of the MachineState
  *    flag of the same name: allows the board to suppress calling of the
  *    CPU do_transaction_failed hook function.
@@ -526,10 +526,13 @@ struct CPUState {
     /* Use by accel-block: CPU is executing an ioctl() */
     QemuLockCnt in_ioctl_lock;
 
-    DECLARE_BITMAP(plugin_mask, QEMU_PLUGIN_EV_MAX);
-
 #ifdef CONFIG_PLUGIN
+    /*
+     * The callback pointer stays in the main CPUState as it is
+     * accessed via TCG (see gen_empty_mem_helper).
+     */
     GArray *plugin_mem_cbs;
+    CPUPluginState *plugin_state;
 #endif
 
     /* TODO Move common fields from CPUArchState here. */

include/qemu/plugin.h

@@ -186,6 +186,19 @@ struct qemu_plugin_insn *qemu_plugin_tb_insn_get(struct qemu_plugin_tb *tb,
     return insn;
 }
 
+/**
+ * struct CPUPluginState - per-CPU state for plugins
+ * @event_mask: plugin event bitmap. Modified only via async work.
+ */
+struct CPUPluginState {
+    DECLARE_BITMAP(event_mask, QEMU_PLUGIN_EV_MAX);
+};
+
+/**
+ * qemu_plugin_create_vcpu_state: allocate plugin state
+ */
+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);

include/qemu/typedefs.h

@@ -42,6 +42,7 @@ typedef struct CompatProperty CompatProperty;
 typedef struct ConfidentialGuestSupport ConfidentialGuestSupport;
 typedef struct CPUAddressSpace CPUAddressSpace;
 typedef struct CPUArchState CPUArchState;
+typedef struct CPUPluginState CPUPluginState;
 typedef struct CpuInfoFast CpuInfoFast;
 typedef struct CPUJumpCache CPUJumpCache;
 typedef struct CPUState CPUState;

plugins/core.c

@@ -17,6 +17,7 @@
 #include "qapi/error.h"
 #include "qemu/lockable.h"
 #include "qemu/option.h"
+#include "qemu/plugin.h"
 #include "qemu/rcu_queue.h"
 #include "qemu/xxhash.h"
 #include "qemu/rcu.h"
@@ -53,7 +54,8 @@ struct qemu_plugin_ctx *plugin_id_to_ctx_locked(qemu_plugin_id_t id)
 
 static void plugin_cpu_update__async(CPUState *cpu, run_on_cpu_data data)
 {
-    bitmap_copy(cpu->plugin_mask, &data.host_ulong, QEMU_PLUGIN_EV_MAX);
+    bitmap_copy(cpu->plugin_state->event_mask,
+                &data.host_ulong, QEMU_PLUGIN_EV_MAX);
     tcg_flush_jmp_cache(cpu);
 }
 
@@ -208,6 +210,11 @@ plugin_register_cb_udata(qemu_plugin_id_t id, enum qemu_plugin_event ev,
     do_plugin_register_cb(id, ev, func, udata);
 }
 
+CPUPluginState *qemu_plugin_create_vcpu_state(void)
+{
+    return g_new0(CPUPluginState, 1);
+}
+
 void qemu_plugin_vcpu_init_hook(CPUState *cpu)
 {
     bool success;
@@ -356,7 +363,7 @@ qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1, uint64_t a2,
     struct qemu_plugin_cb *cb, *next;
     enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_SYSCALL;
 
-    if (!test_bit(ev, cpu->plugin_mask)) {
+    if (!test_bit(ev, cpu->plugin_state->event_mask)) {
         return;
     }
 
@@ -378,7 +385,7 @@ void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret)
     struct qemu_plugin_cb *cb, *next;
     enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_SYSCALL_RET;
 
-    if (!test_bit(ev, cpu->plugin_mask)) {
+    if (!test_bit(ev, cpu->plugin_state->event_mask)) {
         return;
     }