This patch adds various utility functions that may be required to fetch or check
the state of possible vCPUs. It also introduces the concept of *disabled* vCPUs,
which are part of the *possible* vCPUs but are not enabled. This state will be
used during machine initialization and later during the plugging or unplugging
of vCPUs. We release the QOM CPU objects for all disabled vCPUs.
Co-developed-by: Keqian Zhu <zhukeqi...@huawei.com>
Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
Signed-off-by: Salil Mehta <salil.me...@huawei.com>
---
cpu-common.c | 21 ++++++++++++++++++++
include/hw/core/cpu.h | 46 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 67 insertions(+)
diff --git a/cpu-common.c b/cpu-common.c
index 6b262233a3..4a446f6f7f 100644
--- a/cpu-common.c
+++ b/cpu-common.c
@@ -24,6 +24,7 @@
#include "sysemu/cpus.h"
#include "qemu/lockable.h"
#include "trace/trace-root.h"
+#include "hw/boards.h"
QemuMutex qemu_cpu_list_lock;
static QemuCond exclusive_cond;
@@ -108,6 +109,26 @@ void cpu_list_remove(CPUState *cpu)
cpu_list_generation_id++;
}
+CPUState *qemu_get_possible_cpu(int index)
+{
+ MachineState *ms = MACHINE(qdev_get_machine());
+ const CPUArchIdList *possible_cpus = ms->possible_cpus;
+
+ assert((index >= 0) && (index < possible_cpus->len));
+
+ return CPU(possible_cpus->cpus[index].cpu);
+}
+
+bool qemu_present_cpu(CPUState *cpu)
+{
+ return cpu;
+}
+
+bool qemu_enabled_cpu(CPUState *cpu)
+{
+ return cpu && !cpu->disabled;
+}
+
CPUState *qemu_get_cpu(int index)
{
CPUState *cpu;
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 1c9c775df6..73a4e4cce1 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -538,6 +538,20 @@ struct CPUState {
CPUPluginState *plugin_state;
#endif
+ /*
+ * In the guest kernel, the presence of vCPUs is determined by information
+ * provided by the VMM or firmware via the ACPI MADT at boot time. Some
+ * architectures do not allow modifications to this configuration after
+ * the guest has booted. Therefore, for such architectures, hotpluggable
+ * vCPUs are exposed by the VMM as not 'ACPI Enabled' to the kernel.
+ * Within QEMU, such vCPUs (those that are 'yet-to-be-plugged' or have
+ * been hot-unplugged) may either have a `CPUState` object in a 'disabled'
+ * state or may not have a `CPUState` object at all.
+ *
+ * By default, `CPUState` objects are enabled across all architectures.
+ */
+ bool disabled;
+
/* TODO Move common fields from CPUArchState here. */
int cpu_index;
int cluster_index;
@@ -924,6 +938,38 @@ 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.
+ * Input index MUST be in range [0, Max Possible CPUs)
+ *
+ * If CPUState object exists,then it gets a CPU matching
+ * @index in the possible CPU array.
+ *
+ * Returns: The possible CPU or %NULL if CPU does not exist.
+ */
+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);
+
+/**
+ * qemu_enabled_cpu:
+ * @cpu: The vCPU to check
+ *
+ * Checks if the vCPU is enabled.
+ *
+ * Returns: True if it is 'enabled' else false
+ */
+bool qemu_enabled_cpu(CPUState *cpu);
+
/**
* cpu_exists:
* @id: Guest-exposed CPU ID to lookup.
--
2.34.1
