[PATCH RFC 03/22] arm/cpuhp: Add common cpu utility for possible vcpus

[Salil Mehta <salil.mehta@huawei.com>]

Adds various utility functions which might be required to fetch or check the
state of the possible vcpus. This also introduces concept of *disabled* vcpus,
which are part of the *possible* vcpus but are not part of the *present* vcpu.
This state shall be used during machine init time to check the presence of
vcpus.

Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 cpus-common.c         | 20 ++++++++++++++++++++
 include/hw/core/cpu.h | 21 +++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/cpus-common.c b/cpus-common.c
index 70a9d12981..7cf900289b 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -23,6 +23,7 @@
 #include "hw/core/cpu.h"
 #include "sysemu/cpus.h"
 #include "qemu/lockable.h"
+#include "hw/boards.h"
 
 static QemuMutex qemu_cpu_list_lock;
 static QemuCond exclusive_cond;
@@ -82,6 +83,25 @@ void cpu_list_add(CPUState *cpu)
         assert(!cpu_index_auto_assigned);
     }
     QTAILQ_INSERT_TAIL_RCU(&cpus, cpu, node);
+    qemu_mutex_unlock(&qemu_cpu_list_lock);
+}
+
+CPUState *qemu_get_possible_cpu(int index)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    const CPUArchIdList *possible_cpus = ms->possible_cpus;
+    CPUState *cpu;
+
+    assert((index >= 0) && (index < possible_cpus->len));
+
+    cpu = CPU(possible_cpus->cpus[index].cpu);
+
+    return cpu;
+}
+
+bool qemu_present_cpu(CPUState *cpu)
+{
+    return (cpu && !cpu->disabled);
 }
 
 void cpu_list_remove(CPUState *cpu)
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 497600c49e..d9cae71ea5 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -419,6 +419,7 @@ struct CPUState {
 
     GArray *plugin_mem_cbs;
 
+    bool disabled;
     /* TODO Move common fields from CPUArchState here. */
     int cpu_index;
     int cluster_index;
@@ -802,6 +803,26 @@ static inline bool cpu_in_exclusive_context(const CPUState *cpu)
  */
 CPUState *qemu_get_cpu(int index);
 
+/**
+ * qemu_get_possible_cpu:
+ * @index: The CPUState@cpu_index value of the CPU to obtain.
+ *
+ * Gets a CPU matching @index.
+ *
+ * Returns: The possible CPU or %NULL if there is no matching CPU.
+ */
+CPUState *qemu_get_possible_cpu(int index);
+
+/**
+ * qemu_present_cpu:
+ * @cpu: The vCPU to check
+ *
+ * Checks if the vcpu is amongst the present possible vcpus.
+ *
+ * Returns: True if it is present possible vcpu else false
+ */
+bool qemu_present_cpu(CPUState *cpu);
+
 /**
  * cpu_exists:
  * @id: Guest-exposed CPU ID to lookup.
-- 
2.17.1