LoongArch: KVM: Implement fpu operations for vcpu

Implement LoongArch fpu related interface for vcpu, such as get fpu, set
fpu, own fpu and lose fpu, 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

@@ -402,6 +402,62 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	return r;
 }
 
+int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	int i = 0;
+
+	fpu->fcc = vcpu->arch.fpu.fcc;
+	fpu->fcsr = vcpu->arch.fpu.fcsr;
+	for (i = 0; i < NUM_FPU_REGS; i++)
+		memcpy(&fpu->fpr[i], &vcpu->arch.fpu.fpr[i], FPU_REG_WIDTH / 64);
+
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	int i = 0;
+
+	vcpu->arch.fpu.fcc = fpu->fcc;
+	vcpu->arch.fpu.fcsr = fpu->fcsr;
+	for (i = 0; i < NUM_FPU_REGS; i++)
+		memcpy(&vcpu->arch.fpu.fpr[i], &fpu->fpr[i], FPU_REG_WIDTH / 64);
+
+	return 0;
+}
+
+/* Enable FPU and restore context */
+void kvm_own_fpu(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+
+	/* Enable FPU */
+	set_csr_euen(CSR_EUEN_FPEN);
+
+	kvm_restore_fpu(&vcpu->arch.fpu);
+	vcpu->arch.aux_inuse |= KVM_LARCH_FPU;
+	trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_FPU);
+
+	preempt_enable();
+}
+
+/* Save context and disable FPU */
+void kvm_lose_fpu(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+
+	if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
+		kvm_save_fpu(&vcpu->arch.fpu);
+		vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
+		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);
+
+		/* Disable FPU */
+		clear_csr_euen(CSR_EUEN_FPEN);
+	}
+
+	preempt_enable();
+}
+
 int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
 {
 	return 0;