// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
 */

#include <linux/kvm_host.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_vcpu.h>
#include <asm/kvm_csr.h>
#include <asm/kvm_eiointc.h>
#include <asm/kvm_pch_pic.h>

const struct kvm_stats_desc kvm_vm_stats_desc[] = {
        KVM_GENERIC_VM_STATS(),
        STATS_DESC_ICOUNTER(VM, pages),
        STATS_DESC_ICOUNTER(VM, hugepages),
};

const struct kvm_stats_header kvm_vm_stats_header = {
        .name_size = KVM_STATS_NAME_SIZE,
        .num_desc = ARRAY_SIZE(kvm_vm_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_vm_stats_desc),
};

static void kvm_vm_init_features(struct kvm *kvm)
{
        unsigned long val;

        if (cpu_has_lsx)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_LSX);
        if (cpu_has_lasx)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_LASX);
        if (cpu_has_lbt_x86)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_X86BT);
        if (cpu_has_lbt_arm)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_ARMBT);
        if (cpu_has_lbt_mips)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_MIPSBT);
        if (cpu_has_ptw)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PTW);
        if (cpu_has_msgint)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_MSGINT);

        val = read_csr_gcfg();
        if (val & CSR_GCFG_GPMP)
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PMU);

        /* Enable all PV features by default */
        kvm->arch.pv_features |= BIT(KVM_FEATURE_IPI);
        kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PV_IPI);
        if (kvm_pvtime_supported()) {
                kvm->arch.pv_features |= BIT(KVM_FEATURE_PREEMPT);
                kvm->arch.pv_features |= BIT(KVM_FEATURE_STEAL_TIME);
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PV_PREEMPT);
                kvm->arch.kvm_features |= BIT(KVM_LOONGARCH_VM_FEAT_PV_STEALTIME);
        }
}

int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
        int i;

        /* Allocate page table to map GPA -> RPA */
        kvm->arch.pgd = kvm_pgd_alloc();
        if (!kvm->arch.pgd)
                return -ENOMEM;

        kvm->arch.phyid_map = kvzalloc_obj(struct kvm_phyid_map,
                                           GFP_KERNEL_ACCOUNT);
        if (!kvm->arch.phyid_map) {
                free_page((unsigned long)kvm->arch.pgd);
                kvm->arch.pgd = NULL;
                return -ENOMEM;
        }
        spin_lock_init(&kvm->arch.phyid_map_lock);

        kvm_init_vmcs(kvm);
        kvm_vm_init_features(kvm);

        /*
         * cpu_vabits means user address space only (a half of total).
         * GPA size of VM is the same with the size of user address space.
         */
        kvm->arch.gpa_size = BIT(cpu_vabits);
        kvm->arch.root_level = CONFIG_PGTABLE_LEVELS - 1;
        kvm->arch.invalid_ptes[0] = 0;
        kvm->arch.invalid_ptes[1] = (unsigned long)invalid_pte_table;
#if CONFIG_PGTABLE_LEVELS > 2
        kvm->arch.invalid_ptes[2] = (unsigned long)invalid_pmd_table;
#endif
#if CONFIG_PGTABLE_LEVELS > 3
        kvm->arch.invalid_ptes[3] = (unsigned long)invalid_pud_table;
#endif
        for (i = 0; i <= kvm->arch.root_level; i++)
                kvm->arch.pte_shifts[i] = PAGE_SHIFT + i * (PAGE_SHIFT - 3);

        return 0;
}

void kvm_arch_destroy_vm(struct kvm *kvm)
{
        kvm_destroy_vcpus(kvm);
        free_page((unsigned long)kvm->arch.pgd);
        kvm->arch.pgd = NULL;
        kvfree(kvm->arch.phyid_map);
        kvm->arch.phyid_map = NULL;
}

int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
{
        int r;

        switch (ext) {
        case KVM_CAP_IRQCHIP:
        case KVM_CAP_ONE_REG:
        case KVM_CAP_ENABLE_CAP:
        case KVM_CAP_READONLY_MEM:
        case KVM_CAP_IMMEDIATE_EXIT:
        case KVM_CAP_IOEVENTFD:
        case KVM_CAP_MP_STATE:
        case KVM_CAP_SET_GUEST_DEBUG:
                r = 1;
                break;
        case KVM_CAP_NR_VCPUS:
                r = num_online_cpus();
                break;
        case KVM_CAP_MAX_VCPUS:
                r = KVM_MAX_VCPUS;
                break;
        case KVM_CAP_MAX_VCPU_ID:
                r = KVM_MAX_VCPU_IDS;
                break;
        case KVM_CAP_NR_MEMSLOTS:
                r = KVM_USER_MEM_SLOTS;
                break;
        default:
                r = 0;
                break;
        }

        return r;
}

static int kvm_vm_feature_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
{
        switch (attr->attr) {
        case KVM_LOONGARCH_VM_FEAT_LSX:
        case KVM_LOONGARCH_VM_FEAT_LASX:
        case KVM_LOONGARCH_VM_FEAT_X86BT:
        case KVM_LOONGARCH_VM_FEAT_ARMBT:
        case KVM_LOONGARCH_VM_FEAT_MIPSBT:
        case KVM_LOONGARCH_VM_FEAT_PTW:
        case KVM_LOONGARCH_VM_FEAT_MSGINT:
        case KVM_LOONGARCH_VM_FEAT_PMU:
        case KVM_LOONGARCH_VM_FEAT_PV_IPI:
        case KVM_LOONGARCH_VM_FEAT_PV_PREEMPT:
        case KVM_LOONGARCH_VM_FEAT_PV_STEALTIME:
                if (kvm_vm_support(&kvm->arch, attr->attr))
                        return 0;
                return -ENXIO;
        default:
                return -ENXIO;
        }
}

static int kvm_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
{
        switch (attr->group) {
        case KVM_LOONGARCH_VM_FEAT_CTRL:
                return kvm_vm_feature_has_attr(kvm, attr);
        default:
                return -ENXIO;
        }
}

int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
{
        void __user *argp = (void __user *)arg;
        struct kvm *kvm = filp->private_data;
        struct kvm_device_attr attr;

        switch (ioctl) {
        case KVM_CREATE_IRQCHIP:
                return 0;
        case KVM_HAS_DEVICE_ATTR:
                if (copy_from_user(&attr, argp, sizeof(attr)))
                        return -EFAULT;

                return kvm_vm_has_attr(kvm, &attr);
        default:
                return -ENOIOCTLCMD;
        }
}

int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event, bool line_status)
{
        if (!kvm_arch_irqchip_in_kernel(kvm))
                return -ENXIO;

        irq_event->status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
                                        irq_event->irq, irq_event->level, line_status);

        return 0;
}

bool kvm_arch_irqchip_in_kernel(struct kvm *kvm)
{
        return (kvm->arch.ipi && kvm->arch.eiointc && kvm->arch.pch_pic);
}