// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2022 SiFive
 *
 * Authors:
 *     Vincent Chen <vincent.chen@sifive.com>
 *     Greentime Hu <greentime.hu@sifive.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <asm/cpufeature.h>
#include <asm/kvm_vcpu_vector.h>
#include <asm/vector.h>

#ifdef CONFIG_RISCV_ISA_V
void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu)
{
        unsigned long *isa = vcpu->arch.isa;
        struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;

        cntx->sstatus &= ~SR_VS;

        cntx->vector.vlenb = riscv_v_vsize / 32;

        if (riscv_isa_extension_available(isa, v)) {
                cntx->sstatus |= SR_VS_INITIAL;
                WARN_ON(!cntx->vector.datap);
                memset(cntx->vector.datap, 0, riscv_v_vsize);
        } else {
                cntx->sstatus |= SR_VS_OFF;
        }
}

static void kvm_riscv_vcpu_vector_clean(struct kvm_cpu_context *cntx)
{
        cntx->sstatus &= ~SR_VS;
        cntx->sstatus |= SR_VS_CLEAN;
}

void kvm_riscv_vcpu_guest_vector_save(struct kvm_cpu_context *cntx,
                                      unsigned long *isa)
{
        if ((cntx->sstatus & SR_VS) == SR_VS_DIRTY) {
                if (riscv_isa_extension_available(isa, v))
                        __kvm_riscv_vector_save(cntx);
                kvm_riscv_vcpu_vector_clean(cntx);
        }
}

void kvm_riscv_vcpu_guest_vector_restore(struct kvm_cpu_context *cntx,
                                         unsigned long *isa)
{
        if ((cntx->sstatus & SR_VS) != SR_VS_OFF) {
                if (riscv_isa_extension_available(isa, v))
                        __kvm_riscv_vector_restore(cntx);
                kvm_riscv_vcpu_vector_clean(cntx);
        }
}

void kvm_riscv_vcpu_host_vector_save(struct kvm_cpu_context *cntx)
{
        /* No need to check host sstatus as it can be modified outside */
        if (riscv_isa_extension_available(NULL, v))
                __kvm_riscv_vector_save(cntx);
}

void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx)
{
        if (riscv_isa_extension_available(NULL, v))
                __kvm_riscv_vector_restore(cntx);
}

int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu)
{
        vcpu->arch.guest_context.vector.datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
        if (!vcpu->arch.guest_context.vector.datap)
                return -ENOMEM;

        vcpu->arch.host_context.vector.datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
        if (!vcpu->arch.host_context.vector.datap)
                return -ENOMEM;

        return 0;
}

void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu)
{
        kfree(vcpu->arch.guest_context.vector.datap);
        kfree(vcpu->arch.host_context.vector.datap);
}
#endif

static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
                                    unsigned long reg_num,
                                    size_t reg_size,
                                    void **reg_addr)
{
        struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
        size_t vlenb = riscv_v_vsize / 32;

        if (reg_num < KVM_REG_RISCV_VECTOR_REG(0)) {
                if (reg_size != sizeof(unsigned long))
                        return -EINVAL;
                switch (reg_num) {
                case KVM_REG_RISCV_VECTOR_CSR_REG(vstart):
                        *reg_addr = &cntx->vector.vstart;
                        break;
                case KVM_REG_RISCV_VECTOR_CSR_REG(vl):
                        *reg_addr = &cntx->vector.vl;
                        break;
                case KVM_REG_RISCV_VECTOR_CSR_REG(vtype):
                        *reg_addr = &cntx->vector.vtype;
                        break;
                case KVM_REG_RISCV_VECTOR_CSR_REG(vcsr):
                        *reg_addr = &cntx->vector.vcsr;
                        break;
                case KVM_REG_RISCV_VECTOR_CSR_REG(vlenb):
                        *reg_addr = &cntx->vector.vlenb;
                        break;
                case KVM_REG_RISCV_VECTOR_CSR_REG(datap):
                default:
                        return -ENOENT;
                }
        } else if (reg_num <= KVM_REG_RISCV_VECTOR_REG(31)) {
                if (reg_size != vlenb)
                        return -EINVAL;
                *reg_addr = cntx->vector.datap +
                            (reg_num - KVM_REG_RISCV_VECTOR_REG(0)) * vlenb;
        } else {
                return -ENOENT;
        }

        return 0;
}

int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu,
                                  const struct kvm_one_reg *reg)
{
        unsigned long *isa = vcpu->arch.isa;
        unsigned long __user *uaddr =
                        (unsigned long __user *)(unsigned long)reg->addr;
        unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
                                            KVM_REG_SIZE_MASK |
                                            KVM_REG_RISCV_VECTOR);
        size_t reg_size = KVM_REG_SIZE(reg->id);
        void *reg_addr;
        int rc;

        if (!riscv_isa_extension_available(isa, v))
                return -ENOENT;

        rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_addr);
        if (rc)
                return rc;

        if (copy_to_user(uaddr, reg_addr, reg_size))
                return -EFAULT;

        return 0;
}

int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu,
                                  const struct kvm_one_reg *reg)
{
        unsigned long *isa = vcpu->arch.isa;
        unsigned long __user *uaddr =
                        (unsigned long __user *)(unsigned long)reg->addr;
        unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
                                            KVM_REG_SIZE_MASK |
                                            KVM_REG_RISCV_VECTOR);
        size_t reg_size = KVM_REG_SIZE(reg->id);
        void *reg_addr;
        int rc;

        if (!riscv_isa_extension_available(isa, v))
                return -ENOENT;

        if (reg_num == KVM_REG_RISCV_VECTOR_CSR_REG(vlenb)) {
                struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
                unsigned long reg_val;

                if (reg_size != sizeof(reg_val))
                        return -EINVAL;
                if (copy_from_user(&reg_val, uaddr, reg_size))
                        return -EFAULT;
                if (reg_val != cntx->vector.vlenb)
                        return -EINVAL;

                return 0;
        }

        rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_addr);
        if (rc)
                return rc;

        if (copy_from_user(reg_addr, uaddr, reg_size))
                return -EFAULT;

        return 0;
}