accel: Introduce AccelOpsClass::cpus_are_resettable()

Add cpus_are_resettable() to AccelOps, and implement it for the
KVM accelerator.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220207075426.81934-12-f4bug@amsat.org>

accel/kvm/kvm-accel-ops.c

@@ -79,12 +79,18 @@ static bool kvm_vcpu_thread_is_idle(CPUState *cpu)
     return !kvm_halt_in_kernel();
 }
 
+static bool kvm_cpus_are_resettable(void)
+{
+    return !kvm_enabled() || kvm_cpu_check_are_resettable();
+}
+
 static void kvm_accel_ops_class_init(ObjectClass *oc, void *data)
 {
     AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
 
     ops->create_vcpu_thread = kvm_start_vcpu_thread;
     ops->cpu_thread_is_idle = kvm_vcpu_thread_is_idle;
+    ops->cpus_are_resettable = kvm_cpus_are_resettable;
     ops->synchronize_post_reset = kvm_cpu_synchronize_post_reset;
     ops->synchronize_post_init = kvm_cpu_synchronize_post_init;
     ops->synchronize_state = kvm_cpu_synchronize_state;

include/sysemu/accel-ops.h

@@ -28,6 +28,8 @@ struct AccelOpsClass {
     /* initialization function called when accel is chosen */
     void (*ops_init)(AccelOpsClass *ops);
 
+    bool (*cpus_are_resettable)(void);
+
     void (*create_vcpu_thread)(CPUState *cpu); /* MANDATORY NON-NULL */
     void (*kick_vcpu_thread)(CPUState *cpu);
     bool (*cpu_thread_is_idle)(CPUState *cpu);

include/sysemu/hw_accel.h

@@ -23,9 +23,4 @@ void cpu_synchronize_post_reset(CPUState *cpu);
 void cpu_synchronize_post_init(CPUState *cpu);
 void cpu_synchronize_pre_loadvm(CPUState *cpu);
 
-static inline bool cpu_check_are_resettable(void)
-{
-    return kvm_enabled() ? kvm_cpu_check_are_resettable() : true;
-}
-
 #endif /* QEMU_HW_ACCEL_H */

softmmu/cpus.c

@@ -195,7 +195,10 @@ void cpu_synchronize_pre_loadvm(CPUState *cpu)
 
 bool cpus_are_resettable(void)
 {
-    return cpu_check_are_resettable();
+    if (cpus_accel->cpus_are_resettable) {
+        return cpus_accel->cpus_are_resettable();
+    }
+    return true;
 }
 
 int64_t cpus_get_virtual_clock(void)