LoongArch: KVM: Add EIOINTC device support

Add device model for EIOINTC interrupt controller, implement basic
create & destroy interfaces, and register device model to kvm device
table.

Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

3 files changed, 139 insertions, 0 deletions

diff --git a/arch/loongarch/kvm/Makefile b/arch/loongarch/kvm/Makefile
index 36c3009fe89c..bb50fc799c29 100644
--- a/arch/loongarch/kvm/Makefile
+++ b/arch/loongarch/kvm/Makefile
@@ -19,5 +19,6 @@ kvm-y += tlb.o
 kvm-y += vcpu.o
 kvm-y += vm.o
 kvm-y += intc/ipi.o
+kvm-y += intc/eiointc.o
 
 CFLAGS_exit.o	+= $(call cc-option,-Wno-override-init,)
diff --git a/arch/loongarch/kvm/intc/eiointc.c b/arch/loongarch/kvm/intc/eiointc.c
new file mode 100644
index 000000000000..10afa6163643
--- /dev/null
+++ b/arch/loongarch/kvm/intc/eiointc.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Loongson Technology Corporation Limited
+ */
+
+#include <asm/kvm_eiointc.h>
+#include <asm/kvm_vcpu.h>
+#include <linux/count_zeros.h>
+
+static int kvm_eiointc_read(struct kvm_vcpu *vcpu,
+			struct kvm_io_device *dev,
+			gpa_t addr, int len, void *val)
+{
+	return 0;
+}
+
+static int kvm_eiointc_write(struct kvm_vcpu *vcpu,
+			struct kvm_io_device *dev,
+			gpa_t addr, int len, const void *val)
+{
+	return 0;
+}
+
+static const struct kvm_io_device_ops kvm_eiointc_ops = {
+	.read	= kvm_eiointc_read,
+	.write	= kvm_eiointc_write,
+};
+
+static int kvm_eiointc_virt_read(struct kvm_vcpu *vcpu,
+				struct kvm_io_device *dev,
+				gpa_t addr, int len, void *val)
+{
+	return 0;
+}
+
+static int kvm_eiointc_virt_write(struct kvm_vcpu *vcpu,
+				struct kvm_io_device *dev,
+				gpa_t addr, int len, const void *val)
+{
+	return 0;
+}
+
+static const struct kvm_io_device_ops kvm_eiointc_virt_ops = {
+	.read	= kvm_eiointc_virt_read,
+	.write	= kvm_eiointc_virt_write,
+};
+
+static int kvm_eiointc_get_attr(struct kvm_device *dev,
+				struct kvm_device_attr *attr)
+{
+	return 0;
+}
+
+static int kvm_eiointc_set_attr(struct kvm_device *dev,
+				struct kvm_device_attr *attr)
+{
+	return 0;
+}
+
+static int kvm_eiointc_create(struct kvm_device *dev, u32 type)
+{
+	int ret;
+	struct loongarch_eiointc *s;
+	struct kvm_io_device *device, *device1;
+	struct kvm *kvm = dev->kvm;
+
+	/* eiointc has been created */
+	if (kvm->arch.eiointc)
+		return -EINVAL;
+
+	s = kzalloc(sizeof(struct loongarch_eiointc), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	spin_lock_init(&s->lock);
+	s->kvm = kvm;
+
+	/*
+	 * Initialize IOCSR device
+	 */
+	device = &s->device;
+	kvm_iodevice_init(device, &kvm_eiointc_ops);
+	mutex_lock(&kvm->slots_lock);
+	ret = kvm_io_bus_register_dev(kvm, KVM_IOCSR_BUS,
+			EIOINTC_BASE, EIOINTC_SIZE, device);
+	mutex_unlock(&kvm->slots_lock);
+	if (ret < 0) {
+		kfree(s);
+		return ret;
+	}
+
+	device1 = &s->device_vext;
+	kvm_iodevice_init(device1, &kvm_eiointc_virt_ops);
+	ret = kvm_io_bus_register_dev(kvm, KVM_IOCSR_BUS,
+			EIOINTC_VIRT_BASE, EIOINTC_VIRT_SIZE, device1);
+	if (ret < 0) {
+		kvm_io_bus_unregister_dev(kvm, KVM_IOCSR_BUS, &s->device);
+		kfree(s);
+		return ret;
+	}
+	kvm->arch.eiointc = s;
+
+	return 0;
+}
+
+static void kvm_eiointc_destroy(struct kvm_device *dev)
+{
+	struct kvm *kvm;
+	struct loongarch_eiointc *eiointc;
+
+	if (!dev || !dev->kvm || !dev->kvm->arch.eiointc)
+		return;
+
+	kvm = dev->kvm;
+	eiointc = kvm->arch.eiointc;
+	kvm_io_bus_unregister_dev(kvm, KVM_IOCSR_BUS, &eiointc->device);
+	kvm_io_bus_unregister_dev(kvm, KVM_IOCSR_BUS, &eiointc->device_vext);
+	kfree(eiointc);
+}
+
+static struct kvm_device_ops kvm_eiointc_dev_ops = {
+	.name = "kvm-loongarch-eiointc",
+	.create = kvm_eiointc_create,
+	.destroy = kvm_eiointc_destroy,
+	.set_attr = kvm_eiointc_set_attr,
+	.get_attr = kvm_eiointc_get_attr,
+};
+
+int kvm_loongarch_register_eiointc_device(void)
+{
+	return kvm_register_device_ops(&kvm_eiointc_dev_ops, KVM_DEV_TYPE_LOONGARCH_EIOINTC);
+}
diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
index 14f3f69c5bb9..8de366ade99c 100644
--- a/arch/loongarch/kvm/main.c
+++ b/arch/loongarch/kvm/main.c
@@ -9,6 +9,7 @@
 #include <asm/cacheflush.h>
 #include <asm/cpufeature.h>
 #include <asm/kvm_csr.h>
+#include <asm/kvm_eiointc.h>
 #include "trace.h"
 
 unsigned long vpid_mask;
@@ -370,6 +371,11 @@ static int kvm_loongarch_env_init(void)
 
 	/* Register LoongArch IPI interrupt controller interface. */
 	ret = kvm_loongarch_register_ipi_device();
+	if (ret)
+		return ret;
+
+	/* Register LoongArch EIOINTC interrupt controller interface. */
+	ret = kvm_loongarch_register_eiointc_device();
 
 	return ret;
 }