LoongArch: KVM: Implement misc vcpu related interfaces

1, Implement LoongArch vcpu status description such as idle exits
counter, signal exits counter, cpucfg exits counter, etc.

2, Implement some misc vcpu relaterd interfaces, such as vcpu runnable,
vcpu should kick, vcpu dump regs, etc.
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Tested-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/kvm/vcpu.c

@@ -13,6 +13,23 @@
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
+const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
+	KVM_GENERIC_VCPU_STATS(),
+	STATS_DESC_COUNTER(VCPU, int_exits),
+	STATS_DESC_COUNTER(VCPU, idle_exits),
+	STATS_DESC_COUNTER(VCPU, cpucfg_exits),
+	STATS_DESC_COUNTER(VCPU, signal_exits),
+};
+
+const struct kvm_stats_header kvm_vcpu_stats_header = {
+	.name_size = KVM_STATS_NAME_SIZE,
+	.num_desc = ARRAY_SIZE(kvm_vcpu_stats_desc),
+	.id_offset = sizeof(struct kvm_stats_header),
+	.desc_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE,
+	.data_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE +
+		       sizeof(kvm_vcpu_stats_desc),
+};
+
 /*
  * kvm_check_requests - check and handle pending vCPU requests
  *
@@ -141,6 +158,109 @@ static int kvm_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
 	return RESUME_GUEST;
 }
 
+int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
+{
+	return !!(vcpu->arch.irq_pending) &&
+		vcpu->arch.mp_state.mp_state == KVM_MP_STATE_RUNNABLE;
+}
+
+int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
+{
+	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
+}
+
+bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
+{
+	return false;
+}
+
+vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
+{
+	return VM_FAULT_SIGBUS;
+}
+
+int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
+				  struct kvm_translation *tr)
+{
+	return -EINVAL;
+}
+
+int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
+{
+	return kvm_pending_timer(vcpu) ||
+		kvm_read_hw_gcsr(LOONGARCH_CSR_ESTAT) & (1 << INT_TI);
+}
+
+int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu)
+{
+	int i;
+
+	kvm_debug("vCPU Register Dump:\n");
+	kvm_debug("\tPC = 0x%08lx\n", vcpu->arch.pc);
+	kvm_debug("\tExceptions: %08lx\n", vcpu->arch.irq_pending);
+
+	for (i = 0; i < 32; i += 4) {
+		kvm_debug("\tGPR%02d: %08lx %08lx %08lx %08lx\n", i,
+		       vcpu->arch.gprs[i], vcpu->arch.gprs[i + 1],
+		       vcpu->arch.gprs[i + 2], vcpu->arch.gprs[i + 3]);
+	}
+
+	kvm_debug("\tCRMD: 0x%08lx, ESTAT: 0x%08lx\n",
+		  kvm_read_hw_gcsr(LOONGARCH_CSR_CRMD),
+		  kvm_read_hw_gcsr(LOONGARCH_CSR_ESTAT));
+
+	kvm_debug("\tERA: 0x%08lx\n", kvm_read_hw_gcsr(LOONGARCH_CSR_ERA));
+
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
+				struct kvm_mp_state *mp_state)
+{
+	*mp_state = vcpu->arch.mp_state;
+
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
+				struct kvm_mp_state *mp_state)
+{
+	int ret = 0;
+
+	switch (mp_state->mp_state) {
+	case KVM_MP_STATE_RUNNABLE:
+		vcpu->arch.mp_state = *mp_state;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+					struct kvm_guest_debug *dbg)
+{
+	return -EINVAL;
+}
+
+/**
+ * kvm_migrate_count() - Migrate timer.
+ * @vcpu:       Virtual CPU.
+ *
+ * Migrate hrtimer to the current CPU by cancelling and restarting it
+ * if the hrtimer is active.
+ *
+ * Must be called when the vCPU is migrated to a different CPU, so that
+ * the timer can interrupt the guest at the new CPU, and the timer irq can
+ * be delivered to the vCPU.
+ */
+static void kvm_migrate_count(struct kvm_vcpu *vcpu)
+{
+	if (hrtimer_cancel(&vcpu->arch.swtimer))
+		hrtimer_restart(&vcpu->arch.swtimer);
+}
+
 static int _kvm_getcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 *val)
 {
 	unsigned long gintc;