exec: Return CPUState from qemu_get_cpu()

Move the declaration to qemu/cpu.h and add documentation.
The implementation still depends on CPUArchState for CPU iteration.

Signed-off-by: Andreas Färber <afaerber@suse.de>

exec.c

diff --git a/exec.c b/exec.c
index e5265e6..5689613 100644
--- a/exec.c
+++ b/exec.c
@@ -247,10 +247,10 @@
 };
 #endif
 
-CPUArchState *qemu_get_cpu(int index)
+CPUState *qemu_get_cpu(int index)
 {
     CPUArchState *env = first_cpu;
-    CPUState *cpu;
+    CPUState *cpu = NULL;
 
     while (env) {
         cpu = ENV_GET_CPU(env);
@@ -260,7 +260,7 @@
         env = env->next_cpu;
     }
 
-    return env;
+    return cpu;
 }
 
 void cpu_exec_init(CPUArchState *env)

hw/pxa2xx_gpio.c

diff --git a/hw/pxa2xx_gpio.c b/hw/pxa2xx_gpio.c
index c02c295..eec2ea3 100644
--- a/hw/pxa2xx_gpio.c
+++ b/hw/pxa2xx_gpio.c
@@ -277,7 +277,7 @@
 
     s = FROM_SYSBUS(PXA2xxGPIOInfo, dev);
 
-    s->cpu = arm_env_get_cpu(qemu_get_cpu(s->ncpu));
+    s->cpu = ARM_CPU(qemu_get_cpu(s->ncpu));
 
     qdev_init_gpio_in(&dev->qdev, pxa2xx_gpio_set, s->lines);
     qdev_init_gpio_out(&dev->qdev, s->handler, s->lines);

include/exec/cpu-all.h

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 439e88d..249e046 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -354,7 +354,6 @@
 #endif
 
 CPUArchState *cpu_copy(CPUArchState *env);
-CPUArchState *qemu_get_cpu(int cpu);
 
 #define CPU_DUMP_CODE 0x00010000
 #define CPU_DUMP_FPU 0x00020000 /* dump FPU register state, not just integer */

include/qom/cpu.h

diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index d5e0a40..773caf9 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -156,5 +156,15 @@
  */
 void run_on_cpu(CPUState *cpu, void (*func)(void *data), void *data);
 
+/**
+ * qemu_get_cpu:
+ * @index: The CPUState@cpu_index value of the CPU to obtain.
+ *
+ * Gets a CPU matching @index.
+ *
+ * Returns: The CPU or %NULL if there is no matching CPU.
+ */
+CPUState *qemu_get_cpu(int index);
+
 
 #endif

target-mips/op_helper.c

diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
index 1816a0e..1bca4a1 100644
--- a/target-mips/op_helper.c
+++ b/target-mips/op_helper.c
@@ -585,8 +585,9 @@
           walking the list of CPUMIPSStates.  */
 static CPUMIPSState *mips_cpu_map_tc(CPUMIPSState *env, int *tc)
 {
+    MIPSCPU *cpu;
     CPUState *cs;
-    CPUMIPSState *other;
+    CPUState *other_cs;
     int vpe_idx;
     int tc_idx = *tc;
 
@@ -599,8 +600,12 @@
     cs = CPU(mips_env_get_cpu(env));
     vpe_idx = tc_idx / cs->nr_threads;
     *tc = tc_idx % cs->nr_threads;
-    other = qemu_get_cpu(vpe_idx);
-    return other ? other : env;
+    other_cs = qemu_get_cpu(vpe_idx);
+    if (other_cs == NULL) {
+        return env;
+    }
+    cpu = MIPS_CPU(other_cs);
+    return &cpu->env;
 }
 
 /* The per VPE CP0_Status register shares some fields with the per TC