LoongArch: KVM: Register perf callbacks for guest

Add selection for GUEST_PERF_EVENTS if KVM is enabled, also add perf
callback register when KVM module is loading.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: bibo-mao

arch/loongarch/kvm/Kconfig

@@ -33,6 +33,7 @@ config KVM
 	select KVM_MMIO
 	select KVM_XFER_TO_GUEST_WORK
 	select SCHED_INFO
+	select GUEST_PERF_EVENTS if PERF_EVENTS
 	help
 	  Support hosting virtualized guest machines using
 	  hardware virtualization extensions. You will need

arch/loongarch/kvm/main.c

@@ -394,6 +394,7 @@ static int kvm_loongarch_env_init(void)
 	}
 
 	kvm_init_gcsr_flag();
+	kvm_register_perf_callbacks(NULL);
 
 	/* Register LoongArch IPI interrupt controller interface. */
 	ret = kvm_loongarch_register_ipi_device();
@@ -425,6 +426,8 @@ static void kvm_loongarch_env_exit(void)
 		}
 		kfree(kvm_loongarch_ops);
 	}
+
+	kvm_unregister_perf_callbacks();
 }
 
 static int kvm_loongarch_init(void)