monitor: tighten monitor_set_cpu()/get_cpu()

These functions access mon_cpu_path, which is a MonitorHMP-specific
field. Narrowing their signatures from Monitor* to MonitorHMP* makes the
type system enforce what was already true at runtime: every caller is in
an HMP context. The expression parser's MONITOR_HMP() casts are safe
because it is only reachable from handle_hmp_command(), they will be
dropped with later patches.

Reviewed-by: Dr. David Alan Gilbert <dave@treblig.org>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20260828-qemu-no-hmp-v5-36-9227de146347@redhat.com>

4 files changed, 29 insertions, 32 deletions

diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index e2a967516e..89cc19c243 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -182,10 +182,10 @@ void hmp_cpu(MonitorHMP *hmp, const QDict *qdict)
     Monitor *mon = MONITOR(hmp);
     int64_t cpu_index;
 
-    /* XXX: drop the monitor_set_cpu() usage when all HMP commands that
+    /* XXX: drop the monitor_hmp_set_cpu() usage when all HMP commands that
             use it are converted to the QAPI */
     cpu_index = qdict_get_int(qdict, "index");
-    if (monitor_set_cpu(mon, cpu_index) < 0) {
+    if (monitor_hmp_set_cpu(hmp, cpu_index) < 0) {
         monitor_printf(mon, "invalid CPU index\n");
     }
 }
@@ -512,9 +512,8 @@ void hmp_dumpdtb(MonitorHMP *hmp, const QDict *qdict)
 #endif
 
 /* Set the current CPU defined by the user. Callers must hold BQL. */
-int monitor_set_cpu(Monitor *mon, int cpu_index)
+int monitor_hmp_set_cpu(MonitorHMP *hmp, int cpu_index)
 {
-    MonitorHMP *hmp = MONITOR_HMP(mon);
     CPUState *cpu;
 
     cpu = qemu_get_cpu(cpu_index);
@@ -527,9 +526,8 @@ int monitor_set_cpu(Monitor *mon, int cpu_index)
 }
 
 /* Callers must hold BQL. */
-static CPUState *mon_get_cpu_sync(Monitor *mon, bool synchronize)
+static CPUState *monitor_hmp_get_cpu_sync(MonitorHMP *hmp, bool synchronize)
 {
-    MonitorHMP *hmp = MONITOR_HMP(mon);
     CPUState *cpu = NULL;
 
     if (hmp->mon_cpu_path) {
@@ -544,7 +542,7 @@ static CPUState *mon_get_cpu_sync(Monitor *mon, bool synchronize)
         if (!first_cpu) {
             return NULL;
         }
-        monitor_set_cpu(mon, first_cpu->cpu_index);
+        monitor_hmp_set_cpu(hmp, first_cpu->cpu_index);
         cpu = first_cpu;
     }
     assert(cpu != NULL);
@@ -554,21 +552,21 @@ static CPUState *mon_get_cpu_sync(Monitor *mon, bool synchronize)
     return cpu;
 }
 
-CPUState *mon_get_cpu(Monitor *mon)
+CPUState *monitor_hmp_get_cpu(MonitorHMP *hmp)
 {
-    return mon_get_cpu_sync(mon, true);
+    return monitor_hmp_get_cpu_sync(hmp, true);
 }
 
-CPUArchState *mon_get_cpu_env(Monitor *mon)
+CPUArchState *monitor_hmp_get_cpu_env(MonitorHMP *hmp)
 {
-    CPUState *cs = mon_get_cpu(mon);
+    CPUState *cs = monitor_hmp_get_cpu(hmp);
 
     return cs ? cpu_env(cs) : NULL;
 }
 
-int monitor_get_cpu_index(Monitor *mon)
+int monitor_hmp_get_cpu_index(MonitorHMP *hmp)
 {
-    CPUState *cs = mon_get_cpu_sync(mon, false);
+    CPUState *cs = monitor_hmp_get_cpu_sync(hmp, false);
 
     return cs ? cs->cpu_index : UNASSIGNED_CPU_INDEX;
 }
@@ -586,7 +584,7 @@ void hmp_info_registers(MonitorHMP *hmp, const QDict *qdict)
             cpu_dump_state(cs, NULL, CPU_DUMP_FPU | CPU_DUMP_VPU);
         }
     } else {
-        cs = vcpu >= 0 ? qemu_get_cpu(vcpu) : mon_get_cpu(mon);
+        cs = vcpu >= 0 ? qemu_get_cpu(vcpu) : monitor_hmp_get_cpu(hmp);
 
         if (!cs) {
             if (vcpu >= 0) {
@@ -602,13 +600,14 @@ void hmp_info_registers(MonitorHMP *hmp, const QDict *qdict)
     }
 }
 
-static void memory_dump(Monitor *mon, int count, int format, int wsize,
+static void memory_dump(MonitorHMP *hmp, int count, int format, int wsize,
                         uint64_t addr, bool is_physical)
 {
+    Monitor *mon = MONITOR(hmp);
     int l, line_size, i, max_digits, len;
     uint8_t buf[16];
     uint64_t v;
-    CPUState *cs = mon_get_cpu(mon);
+    CPUState *cs = monitor_hmp_get_cpu(hmp);
     const unsigned int addr_width = is_physical ? 8 : (target_long_bits() / 4);
     const bool big_endian = target_big_endian();
 
@@ -712,24 +711,22 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize,
 
 void hmp_memory_dump(MonitorHMP *hmp, const QDict *qdict)
 {
-    Monitor *mon = MONITOR(hmp);
     int count = qdict_get_int(qdict, "count");
     int format = qdict_get_int(qdict, "format");
     int size = qdict_get_int(qdict, "size");
     vaddr addr = qdict_get_int(qdict, "addr");
 
-    memory_dump(mon, count, format, size, addr, false);
+    memory_dump(hmp, count, format, size, addr, false);
 }
 
 void hmp_physical_memory_dump(MonitorHMP *hmp, const QDict *qdict)
 {
-    Monitor *mon = MONITOR(hmp);
     int count = qdict_get_int(qdict, "count");
     int format = qdict_get_int(qdict, "format");
     int size = qdict_get_int(qdict, "size");
     hwaddr addr = qdict_get_int(qdict, "addr");
 
-    memory_dump(mon, count, format, size, addr, true);
+    memory_dump(hmp, count, format, size, addr, true);
 }
 
 void hmp_gpa2hva(MonitorHMP *hmp, const QDict *qdict)
@@ -757,7 +754,7 @@ void hmp_gva2gpa(MonitorHMP *hmp, const QDict *qdict)
 {
     Monitor *mon = MONITOR(hmp);
     vaddr addr = qdict_get_int(qdict, "addr");
-    CPUState *cs = mon_get_cpu(mon);
+    CPUState *cs = monitor_hmp_get_cpu(hmp);
     TranslateForDebugResult tres;
 
     if (!cs) {
diff --git a/monitor/hmp.c b/monitor/hmp.c
index 47fb7cef6d..2484a2310d 100644
--- a/monitor/hmp.c
+++ b/monitor/hmp.c
@@ -411,10 +411,10 @@ void hmp_help_cmd(Monitor *mon, const char *name)
  * Set @pval to the value in the register identified by @name.
  * return %true if the register is found, %false otherwise.
  */
-static bool gdb_get_register(Monitor *mon, int64_t *pval, const char *name)
+static bool gdb_get_register(MonitorHMP *hmp, int64_t *pval, const char *name)
 {
     g_autoptr(GArray) regs = NULL;
-    CPUState *cs = mon_get_cpu(mon);
+    CPUState *cs = monitor_hmp_get_cpu(hmp);
 
     if (cs == NULL) {
         return false;
@@ -452,7 +452,7 @@ static bool gdb_get_register(Monitor *mon, int64_t *pval, const char *name)
 static const char *pch;
 static sigjmp_buf expr_env;
 
-static int get_monitor_def(Monitor *mon, int64_t *pval, const char *name);
+static int get_monitor_def(MonitorHMP *mon, int64_t *pval, const char *name);
 
 static G_NORETURN G_GNUC_PRINTF(2, 3)
 void expr_error(Monitor *mon, const char *fmt, ...)
@@ -535,8 +535,8 @@ static int64_t expr_unary(Monitor *mon)
                 pch++;
             }
             *q = 0;
-            if (!gdb_get_register(mon, &reg, buf)
-                && get_monitor_def(mon, &reg, buf) < 0) {
+            if (!gdb_get_register(MONITOR_HMP(mon), &reg, buf)
+                && get_monitor_def(MONITOR_HMP(mon), &reg, buf) < 0) {
                 expr_error(mon, "unknown register");
             }
             n = reg;
@@ -1733,9 +1733,9 @@ void monitor_register_hmp_info_hrt(const char *name,
  * Set @pval to the value in the register identified by @name.
  * return 0 if OK, -1 if not found
  */
-static int get_monitor_def(Monitor *mon, int64_t *pval, const char *name)
+static int get_monitor_def(MonitorHMP *hmp, int64_t *pval, const char *name)
 {
-    CPUState *cs = mon_get_cpu(mon);
+    CPUState *cs = monitor_hmp_get_cpu(hmp);
     const MonitorDef *md;
     void *ptr;
 
@@ -1750,9 +1750,9 @@ static int get_monitor_def(Monitor *mon, int64_t *pval, const char *name)
     for (; md->name != NULL; md++) {
         if (hmp_compare_cmd(name, md->name)) {
             if (md->get_value) {
-                *pval = md->get_value(mon, md, md->offset);
+                *pval = md->get_value(hmp, md, md->offset);
             } else {
-                CPUArchState *env = mon_get_cpu_env(mon);
+                CPUArchState *env = monitor_hmp_get_cpu_env(hmp);
                 ptr = (uint8_t *)env + md->offset;
                 *pval = *(int32_t *)ptr;
             }
diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h
index a0fa37c887..afdda13860 100644
--- a/monitor/monitor-internal.h
+++ b/monitor/monitor-internal.h
@@ -215,7 +215,7 @@ int monitor_can_read(void *opaque);
 void monitor_cancel_out_watch(Monitor *mon);
 void monitor_list_append(Monitor *mon);
 void monitor_fdsets_cleanup(void);
-int monitor_set_cpu(Monitor *mon, int cpu_index);
+int monitor_hmp_set_cpu(MonitorHMP *mon, int cpu_index);
 
 void qmp_send_response(MonitorQMP *mon, const QDict *rsp);
 void monitor_data_destroy_qmp(MonitorQMP *mon);
diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
index 6cb0b587fb..b16119f485 100644
--- a/monitor/qmp-cmds.c
+++ b/monitor/qmp-cmds.c
@@ -169,7 +169,7 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
     MonitorHMP *hmp = MONITOR_HMP(object_new(TYPE_MONITOR_HMP));
 
     if (has_cpu_index) {
-        int ret = monitor_set_cpu(&hmp->parent_obj, cpu_index);
+        int ret = monitor_hmp_set_cpu(hmp, cpu_index);
         if (ret < 0) {
             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu-index",
                        "a CPU number");