LoongArch: KVM: Add PCHPIC device support

Add device model for PCHPIC interrupt controller, implemente basic
create & destroy interface, 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>

arch/loongarch/include/asm/kvm_host.h

@@ -20,6 +20,7 @@
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_ipi.h>
 #include <asm/kvm_eiointc.h>
+#include <asm/kvm_pch_pic.h>
 #include <asm/loongarch.h>
 
 /* Loongarch KVM register ids */
@@ -125,6 +126,7 @@ struct kvm_arch {
 	struct kvm_context __percpu *vmcs;
 	struct loongarch_ipi *ipi;
 	struct loongarch_eiointc *eiointc;
+	struct loongarch_pch_pic *pch_pic;
 };
 
 #define CSR_MAX_NUMS		0x800

arch/loongarch/include/asm/kvm_pch_pic.h

@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Loongson Technology Corporation Limited
+ */
+
+#ifndef __ASM_KVM_PCH_PIC_H
+#define __ASM_KVM_PCH_PIC_H
+
+#include <kvm/iodev.h>
+
+struct loongarch_pch_pic {
+	spinlock_t lock;
+	struct kvm *kvm;
+	struct kvm_io_device device;
+	uint64_t mask; /* 1:disable irq, 0:enable irq */
+	uint64_t htmsi_en; /* 1:msi */
+	uint64_t edge; /* 1:edge triggered, 0:level triggered */
+	uint64_t auto_ctrl0; /* only use default value 00b */
+	uint64_t auto_ctrl1; /* only use default value 00b */
+	uint64_t last_intirr; /* edge detection */
+	uint64_t irr; /* interrupt request register */
+	uint64_t isr; /* interrupt service register */
+	uint64_t polarity; /* 0: high level trigger, 1: low level trigger */
+	uint8_t  route_entry[64]; /* default value 0, route to int0: eiointc */
+	uint8_t  htmsi_vector[64]; /* irq route table for routing to eiointc */
+	uint64_t pch_pic_base;
+};
+
+int kvm_loongarch_register_pch_pic_device(void);
+
+#endif /* __ASM_KVM_PCH_PIC_H */

arch/loongarch/kvm/Makefile

@@ -20,5 +20,6 @@ kvm-y += vcpu.o
 kvm-y += vm.o
 kvm-y += intc/ipi.o
 kvm-y += intc/eiointc.o
+kvm-y += intc/pch_pic.o
 
 CFLAGS_exit.o	+= $(call cc-option,-Wno-override-init,)

arch/loongarch/kvm/intc/pch_pic.c

@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Loongson Technology Corporation Limited
+ */
+
+#include <asm/kvm_eiointc.h>
+#include <asm/kvm_pch_pic.h>
+#include <asm/kvm_vcpu.h>
+#include <linux/count_zeros.h>
+
+static int kvm_pch_pic_read(struct kvm_vcpu *vcpu,
+			struct kvm_io_device *dev,
+			gpa_t addr, int len, void *val)
+{
+	return 0;
+}
+
+static int kvm_pch_pic_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_pch_pic_ops = {
+	.read	= kvm_pch_pic_read,
+	.write	= kvm_pch_pic_write,
+};
+
+static int kvm_pch_pic_get_attr(struct kvm_device *dev,
+				struct kvm_device_attr *attr)
+{
+	return 0;
+}
+
+static int kvm_pch_pic_set_attr(struct kvm_device *dev,
+				struct kvm_device_attr *attr)
+{
+	return 0;
+}
+
+static int kvm_pch_pic_create(struct kvm_device *dev, u32 type)
+{
+	struct kvm *kvm = dev->kvm;
+	struct loongarch_pch_pic *s;
+
+	/* pch pic should not has been created */
+	if (kvm->arch.pch_pic)
+		return -EINVAL;
+
+	s = kzalloc(sizeof(struct loongarch_pch_pic), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	spin_lock_init(&s->lock);
+	s->kvm = kvm;
+	kvm->arch.pch_pic = s;
+
+	return 0;
+}
+
+static void kvm_pch_pic_destroy(struct kvm_device *dev)
+{
+	struct kvm *kvm;
+	struct loongarch_pch_pic *s;
+
+	if (!dev || !dev->kvm || !dev->kvm->arch.pch_pic)
+		return;
+
+	kvm = dev->kvm;
+	s = kvm->arch.pch_pic;
+	/* unregister pch pic device and free it's memory */
+	kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &s->device);
+	kfree(s);
+}
+
+static struct kvm_device_ops kvm_pch_pic_dev_ops = {
+	.name = "kvm-loongarch-pch-pic",
+	.create = kvm_pch_pic_create,
+	.destroy = kvm_pch_pic_destroy,
+	.set_attr = kvm_pch_pic_set_attr,
+	.get_attr = kvm_pch_pic_get_attr,
+};
+
+int kvm_loongarch_register_pch_pic_device(void)
+{
+	return kvm_register_device_ops(&kvm_pch_pic_dev_ops, KVM_DEV_TYPE_LOONGARCH_PCHPIC);
+}

arch/loongarch/kvm/main.c

@@ -10,6 +10,7 @@
 #include <asm/cpufeature.h>
 #include <asm/kvm_csr.h>
 #include <asm/kvm_eiointc.h>
+#include <asm/kvm_pch_pic.h>
 #include "trace.h"
 
 unsigned long vpid_mask;
@@ -376,6 +377,11 @@ static int kvm_loongarch_env_init(void)
 
 	/* Register LoongArch EIOINTC interrupt controller interface. */
 	ret = kvm_loongarch_register_eiointc_device();
+	if (ret)
+		return ret;
+
+	/* Register LoongArch PCH-PIC interrupt controller interface. */
+	ret = kvm_loongarch_register_pch_pic_device();
 
 	return ret;
 }

include/uapi/linux/kvm.h

@@ -1162,6 +1162,8 @@ enum kvm_device_type {
 #define KVM_DEV_TYPE_LOONGARCH_IPI	KVM_DEV_TYPE_LOONGARCH_IPI
 	KVM_DEV_TYPE_LOONGARCH_EIOINTC,
 #define KVM_DEV_TYPE_LOONGARCH_EIOINTC	KVM_DEV_TYPE_LOONGARCH_EIOINTC
+	KVM_DEV_TYPE_LOONGARCH_PCHPIC,
+#define KVM_DEV_TYPE_LOONGARCH_PCHPIC	KVM_DEV_TYPE_LOONGARCH_PCHPIC
 
 	KVM_DEV_TYPE_MAX,