hw/core: Use a callback for target specific query-cpus-fast information

For being able to create a universal QEMU binary one day, core
files like machine-qmp-cmds.c must not contain any "#ifdef TARGET_..."
parts. Thus let's provide the target specific function via a
function pointer in CPUClass instead, as a first step towards
making this file target independent.

Message-Id: <20230424160434.331175-2-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/core/machine-qmp-cmds.c

@@ -28,18 +28,6 @@
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
 
-static void cpustate_to_cpuinfo_s390(CpuInfoS390 *info, const CPUState *cpu)
-{
-#ifdef TARGET_S390X
-    S390CPU *s390_cpu = S390_CPU(cpu);
-    CPUS390XState *env = &s390_cpu->env;
-
-    info->cpu_state = env->cpu_state;
-#else
-    abort();
-#endif
-}
-
 /*
  * fast means: we NEVER interrupt vCPU threads to retrieve
  * information from KVM.
@@ -68,8 +56,8 @@ CpuInfoFastList *qmp_query_cpus_fast(Error **errp)
         }
 
         value->target = target;
-        if (target == SYS_EMU_TARGET_S390X) {
-            cpustate_to_cpuinfo_s390(&value->u.s390x, cpu);
+        if (cpu->cc->query_cpu_fast) {
+            cpu->cc->query_cpu_fast(cpu, value);
         }
 
         QAPI_LIST_APPEND(tail, value);

include/hw/core/cpu.h

@@ -106,6 +106,9 @@ struct SysemuCPUOps;
  * @has_work: Callback for checking if there is work to do.
  * @memory_rw_debug: Callback for GDB memory access.
  * @dump_state: Callback for dumping state.
+ * @query_cpu_fast:
+ *       Fill in target specific information for the "query-cpus-fast"
+ *       QAPI call.
  * @get_arch_id: Callback for getting architecture-dependent CPU ID.
  * @set_pc: Callback for setting the Program Counter register. This
  *       should have the semantics used by the target architecture when
@@ -151,6 +154,7 @@ struct CPUClass {
     int (*memory_rw_debug)(CPUState *cpu, vaddr addr,
                            uint8_t *buf, int len, bool is_write);
     void (*dump_state)(CPUState *cpu, FILE *, int flags);
+    void (*query_cpu_fast)(CPUState *cpu, CpuInfoFast *value);
     int64_t (*get_arch_id)(CPUState *cpu);
     void (*set_pc)(CPUState *cpu, vaddr value);
     vaddr (*get_pc)(CPUState *cpu);

include/qemu/typedefs.h

@@ -41,6 +41,7 @@ typedef struct CompatProperty CompatProperty;
 typedef struct ConfidentialGuestSupport ConfidentialGuestSupport;
 typedef struct CPUAddressSpace CPUAddressSpace;
 typedef struct CPUArchState CPUArchState;
+typedef struct CpuInfoFast CpuInfoFast;
 typedef struct CPUJumpCache CPUJumpCache;
 typedef struct CPUState CPUState;
 typedef struct CPUTLBEntryFull CPUTLBEntryFull;

target/s390x/cpu.c

@@ -140,6 +140,13 @@ static bool s390_cpu_has_work(CPUState *cs)
     return s390_cpu_has_int(cpu);
 }
 
+static void s390_query_cpu_fast(CPUState *cpu, CpuInfoFast *value)
+{
+    S390CPU *s390_cpu = S390_CPU(cpu);
+
+    value->u.s390x.cpu_state = s390_cpu->env.cpu_state;
+}
+
 /* S390CPUClass::reset() */
 static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
 {
@@ -332,6 +339,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     cc->class_by_name = s390_cpu_class_by_name,
     cc->has_work = s390_cpu_has_work;
     cc->dump_state = s390_cpu_dump_state;
+    cc->query_cpu_fast = s390_query_cpu_fast;
     cc->set_pc = s390_cpu_set_pc;
     cc->get_pc = s390_cpu_get_pc;
     cc->gdb_read_register = s390_cpu_gdb_read_register;