/*
 * Copyright (C) 2008-2011 Freescale Semiconductor, Inc. All rights reserved.
 *
 * Author: Yu Liu, <yu.liu@freescale.com>
 *
 * Description:
 * This file is derived from arch/powerpc/kvm/44x.c,
 * by Hollis Blanchard <hollisb@us.ibm.com>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 */

#include <linux/kvm_host.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/miscdevice.h>

#include <asm/reg.h>
#include <asm/cputable.h>
#include <asm/tlbflush.h>
#include <asm/kvm_ppc.h>

#include "../mm/mmu_decl.h"
#include "booke.h"
#include "e500.h"

struct id {
        unsigned long val;
        struct id **pentry;
};

#define NUM_TIDS 256

/*
 * This table provide mappings from:
 * (guestAS,guestTID,guestPR) --> ID of physical cpu
 * guestAS      [0..1]
 * guestTID     [0..255]
 * guestPR      [0..1]
 * ID           [1..255]
 * Each vcpu keeps one vcpu_id_table.
 */
struct vcpu_id_table {
        struct id id[2][NUM_TIDS][2];
};

/*
 * This table provide reversed mappings of vcpu_id_table:
 * ID --> address of vcpu_id_table item.
 * Each physical core has one pcpu_id_table.
 */
struct pcpu_id_table {
        struct id *entry[NUM_TIDS];
};

static DEFINE_PER_CPU(struct pcpu_id_table, pcpu_sids);

/* This variable keeps last used shadow ID on local core.
 * The valid range of shadow ID is [1..255] */
static DEFINE_PER_CPU(unsigned long, pcpu_last_used_sid);

/*
 * Allocate a free shadow id and setup a valid sid mapping in given entry.
 * A mapping is only valid when vcpu_id_table and pcpu_id_table are match.
 *
 * The caller must have preemption disabled, and keep it that way until
 * it has finished with the returned shadow id (either written into the
 * TLB or arch.shadow_pid, or discarded).
 */
static inline int local_sid_setup_one(struct id *entry)
{
        unsigned long sid;
        int ret = -1;

        sid = __this_cpu_inc_return(pcpu_last_used_sid);
        if (sid < NUM_TIDS) {
                __this_cpu_write(pcpu_sids.entry[sid], entry);
                entry->val = sid;
                entry->pentry = this_cpu_ptr(&pcpu_sids.entry[sid]);
                ret = sid;
        }

        /*
         * If sid == NUM_TIDS, we've run out of sids.  We return -1, and
         * the caller will invalidate everything and start over.
         *
         * sid > NUM_TIDS indicates a race, which we disable preemption to
         * avoid.
         */
        WARN_ON(sid > NUM_TIDS);

        return ret;
}

/*
 * Check if given entry contain a valid shadow id mapping.
 * An ID mapping is considered valid only if
 * both vcpu and pcpu know this mapping.
 *
 * The caller must have preemption disabled, and keep it that way until
 * it has finished with the returned shadow id (either written into the
 * TLB or arch.shadow_pid, or discarded).
 */
static inline int local_sid_lookup(struct id *entry)
{
        if (entry && entry->val != 0 &&
            __this_cpu_read(pcpu_sids.entry[entry->val]) == entry &&
            entry->pentry == this_cpu_ptr(&pcpu_sids.entry[entry->val]))
                return entry->val;
        return -1;
}

/* Invalidate all id mappings on local core -- call with preempt disabled */
static inline void local_sid_destroy_all(void)
{
        __this_cpu_write(pcpu_last_used_sid, 0);
        memset(this_cpu_ptr(&pcpu_sids), 0, sizeof(pcpu_sids));
}

static void *kvmppc_e500_id_table_alloc(struct kvmppc_vcpu_e500 *vcpu_e500)
{
        vcpu_e500->idt = kzalloc(sizeof(struct vcpu_id_table), GFP_KERNEL);
        return vcpu_e500->idt;
}

static void kvmppc_e500_id_table_free(struct kvmppc_vcpu_e500 *vcpu_e500)
{
        kfree(vcpu_e500->idt);
        vcpu_e500->idt = NULL;
}

/* Map guest pid to shadow.
 * We use PID to keep shadow of current guest non-zero PID,
 * and use PID1 to keep shadow of guest zero PID.
 * So that guest tlbe with TID=0 can be accessed at any time */
static void kvmppc_e500_recalc_shadow_pid(struct kvmppc_vcpu_e500 *vcpu_e500)
{
        preempt_disable();
        vcpu_e500->vcpu.arch.shadow_pid = kvmppc_e500_get_sid(vcpu_e500,
                        get_cur_as(&vcpu_e500->vcpu),
                        get_cur_pid(&vcpu_e500->vcpu),
                        get_cur_pr(&vcpu_e500->vcpu), 1);
        vcpu_e500->vcpu.arch.shadow_pid1 = kvmppc_e500_get_sid(vcpu_e500,
                        get_cur_as(&vcpu_e500->vcpu), 0,
                        get_cur_pr(&vcpu_e500->vcpu), 1);
        preempt_enable();
}

/* Invalidate all mappings on vcpu */
static void kvmppc_e500_id_table_reset_all(struct kvmppc_vcpu_e500 *vcpu_e500)
{
        memset(vcpu_e500->idt, 0, sizeof(struct vcpu_id_table));

        /* Update shadow pid when mappings are changed */
        kvmppc_e500_recalc_shadow_pid(vcpu_e500);
}

/* Invalidate one ID mapping on vcpu */
static inline void kvmppc_e500_id_table_reset_one(
                               struct kvmppc_vcpu_e500 *vcpu_e500,
                               int as, int pid, int pr)
{
        struct vcpu_id_table *idt = vcpu_e500->idt;

        BUG_ON(as >= 2);
        BUG_ON(pid >= NUM_TIDS);
        BUG_ON(pr >= 2);

        idt->id[as][pid][pr].val = 0;
        idt->id[as][pid][pr].pentry = NULL;

        /* Update shadow pid when mappings are changed */
        kvmppc_e500_recalc_shadow_pid(vcpu_e500);
}

/*
 * Map guest (vcpu,AS,ID,PR) to physical core shadow id.
 * This function first lookup if a valid mapping exists,
 * if not, then creates a new one.
 *
 * The caller must have preemption disabled, and keep it that way until
 * it has finished with the returned shadow id (either written into the
 * TLB or arch.shadow_pid, or discarded).
 */
unsigned int kvmppc_e500_get_sid(struct kvmppc_vcpu_e500 *vcpu_e500,
                                 unsigned int as, unsigned int gid,
                                 unsigned int pr, int avoid_recursion)
{
        struct vcpu_id_table *idt = vcpu_e500->idt;
        int sid;

        BUG_ON(as >= 2);
        BUG_ON(gid >= NUM_TIDS);
        BUG_ON(pr >= 2);

        sid = local_sid_lookup(&idt->id[as][gid][pr]);

        while (sid <= 0) {
                /* No mapping yet */
                sid = local_sid_setup_one(&idt->id[as][gid][pr]);
                if (sid <= 0) {
                        _tlbil_all();
                        local_sid_destroy_all();
                }

                /* Update shadow pid when mappings are changed */
                if (!avoid_recursion)
                        kvmppc_e500_recalc_shadow_pid(vcpu_e500);
        }

        return sid;
}

unsigned int kvmppc_e500_get_tlb_stid(struct kvm_vcpu *vcpu,
                                      struct kvm_book3e_206_tlb_entry *gtlbe)
{
        return kvmppc_e500_get_sid(to_e500(vcpu), get_tlb_ts(gtlbe),
                                   get_tlb_tid(gtlbe), get_cur_pr(vcpu), 0);
}

void kvmppc_set_pid(struct kvm_vcpu *vcpu, u32 pid)
{
        struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);

        if (vcpu->arch.pid != pid) {
                vcpu_e500->pid[0] = vcpu->arch.pid = pid;
                kvmppc_e500_recalc_shadow_pid(vcpu_e500);
        }
}

/* gtlbe must not be mapped by more than one host tlbe */
void kvmppc_e500_tlbil_one(struct kvmppc_vcpu_e500 *vcpu_e500,
                           struct kvm_book3e_206_tlb_entry *gtlbe)
{
        struct vcpu_id_table *idt = vcpu_e500->idt;
        unsigned int pr, tid, ts;
        int pid;
        u32 val, eaddr;
        unsigned long flags;

        ts = get_tlb_ts(gtlbe);
        tid = get_tlb_tid(gtlbe);

        preempt_disable();

        /* One guest ID may be mapped to two shadow IDs */
        for (pr = 0; pr < 2; pr++) {
                /*
                 * The shadow PID can have a valid mapping on at most one
                 * host CPU.  In the common case, it will be valid on this
                 * CPU, in which case we do a local invalidation of the
                 * specific address.
                 *
                 * If the shadow PID is not valid on the current host CPU,
                 * we invalidate the entire shadow PID.
                 */
                pid = local_sid_lookup(&idt->id[ts][tid][pr]);
                if (pid <= 0) {
                        kvmppc_e500_id_table_reset_one(vcpu_e500, ts, tid, pr);
                        continue;
                }

                /*
                 * The guest is invalidating a 4K entry which is in a PID
                 * that has a valid shadow mapping on this host CPU.  We
                 * search host TLB to invalidate it's shadow TLB entry,
                 * similar to __tlbil_va except that we need to look in AS1.
                 */
                val = (pid << MAS6_SPID_SHIFT) | MAS6_SAS;
                eaddr = get_tlb_eaddr(gtlbe);

                local_irq_save(flags);

                mtspr(SPRN_MAS6, val);
                asm volatile("tlbsx 0, %[eaddr]" : : [eaddr] "r" (eaddr));
                val = mfspr(SPRN_MAS1);
                if (val & MAS1_VALID) {
                        mtspr(SPRN_MAS1, val & ~MAS1_VALID);
                        asm volatile("tlbwe");
                }

                local_irq_restore(flags);
        }

        preempt_enable();
}

void kvmppc_e500_tlbil_all(struct kvmppc_vcpu_e500 *vcpu_e500)
{
        kvmppc_e500_id_table_reset_all(vcpu_e500);
}

void kvmppc_mmu_msr_notify(struct kvm_vcpu *vcpu, u32 old_msr)
{
        /* Recalc shadow pid since MSR changes */
        kvmppc_e500_recalc_shadow_pid(to_e500(vcpu));
}

static void kvmppc_core_vcpu_load_e500(struct kvm_vcpu *vcpu, int cpu)
{
        kvmppc_booke_vcpu_load(vcpu, cpu);

        /* Shadow PID may be expired on local core */
        kvmppc_e500_recalc_shadow_pid(to_e500(vcpu));
}

static void kvmppc_core_vcpu_put_e500(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_SPE
        if (vcpu->arch.shadow_msr & MSR_SPE)
                kvmppc_vcpu_disable_spe(vcpu);
#endif

        kvmppc_booke_vcpu_put(vcpu);
}

int kvmppc_core_check_processor_compat(void)
{
        int r;

        if (strcmp(cur_cpu_spec->cpu_name, "e500v2") == 0)
                r = 0;
        else
                r = -ENOTSUPP;

        return r;
}

static void kvmppc_e500_tlb_setup(struct kvmppc_vcpu_e500 *vcpu_e500)
{
        struct kvm_book3e_206_tlb_entry *tlbe;

        /* Insert large initial mapping for guest. */
        tlbe = get_entry(vcpu_e500, 1, 0);
        tlbe->mas1 = MAS1_VALID | MAS1_TSIZE(BOOK3E_PAGESZ_256M);
        tlbe->mas2 = 0;
        tlbe->mas7_3 = E500_TLB_SUPER_PERM_MASK;

        /* 4K map for serial output. Used by kernel wrapper. */
        tlbe = get_entry(vcpu_e500, 1, 1);
        tlbe->mas1 = MAS1_VALID | MAS1_TSIZE(BOOK3E_PAGESZ_4K);
        tlbe->mas2 = (0xe0004500 & 0xFFFFF000) | MAS2_I | MAS2_G;
        tlbe->mas7_3 = (0xe0004500 & 0xFFFFF000) | E500_TLB_SUPER_PERM_MASK;
}

int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu)
{
        struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);

        kvmppc_e500_tlb_setup(vcpu_e500);

        /* Registers init */
        vcpu->arch.pvr = mfspr(SPRN_PVR);
        vcpu_e500->svr = mfspr(SPRN_SVR);

        vcpu->arch.cpu_type = KVM_CPU_E500V2;

        return 0;
}

static int kvmppc_core_get_sregs_e500(struct kvm_vcpu *vcpu,
                                      struct kvm_sregs *sregs)
{
        struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);

        sregs->u.e.features |= KVM_SREGS_E_ARCH206_MMU | KVM_SREGS_E_SPE |
                               KVM_SREGS_E_PM;
        sregs->u.e.impl_id = KVM_SREGS_E_IMPL_FSL;

        sregs->u.e.impl.fsl.features = 0;
        sregs->u.e.impl.fsl.svr = vcpu_e500->svr;
        sregs->u.e.impl.fsl.hid0 = vcpu_e500->hid0;
        sregs->u.e.impl.fsl.mcar = vcpu_e500->mcar;

        sregs->u.e.ivor_high[0] = vcpu->arch.ivor[BOOKE_IRQPRIO_SPE_UNAVAIL];
        sregs->u.e.ivor_high[1] = vcpu->arch.ivor[BOOKE_IRQPRIO_SPE_FP_DATA];
        sregs->u.e.ivor_high[2] = vcpu->arch.ivor[BOOKE_IRQPRIO_SPE_FP_ROUND];
        sregs->u.e.ivor_high[3] =
                vcpu->arch.ivor[BOOKE_IRQPRIO_PERFORMANCE_MONITOR];

        kvmppc_get_sregs_ivor(vcpu, sregs);
        kvmppc_get_sregs_e500_tlb(vcpu, sregs);
        return 0;
}

static int kvmppc_core_set_sregs_e500(struct kvm_vcpu *vcpu,
                                      struct kvm_sregs *sregs)
{
        struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
        int ret;

        if (sregs->u.e.impl_id == KVM_SREGS_E_IMPL_FSL) {
                vcpu_e500->svr = sregs->u.e.impl.fsl.svr;
                vcpu_e500->hid0 = sregs->u.e.impl.fsl.hid0;
                vcpu_e500->mcar = sregs->u.e.impl.fsl.mcar;
        }

        ret = kvmppc_set_sregs_e500_tlb(vcpu, sregs);
        if (ret < 0)
                return ret;

        if (!(sregs->u.e.features & KVM_SREGS_E_IVOR))
                return 0;

        if (sregs->u.e.features & KVM_SREGS_E_SPE) {
                vcpu->arch.ivor[BOOKE_IRQPRIO_SPE_UNAVAIL] =
                        sregs->u.e.ivor_high[0];
                vcpu->arch.ivor[BOOKE_IRQPRIO_SPE_FP_DATA] =
                        sregs->u.e.ivor_high[1];
                vcpu->arch.ivor[BOOKE_IRQPRIO_SPE_FP_ROUND] =
                        sregs->u.e.ivor_high[2];
        }

        if (sregs->u.e.features & KVM_SREGS_E_PM) {
                vcpu->arch.ivor[BOOKE_IRQPRIO_PERFORMANCE_MONITOR] =
                        sregs->u.e.ivor_high[3];
        }

        return kvmppc_set_sregs_ivor(vcpu, sregs);
}

static int kvmppc_get_one_reg_e500(struct kvm_vcpu *vcpu, u64 id,
                                   union kvmppc_one_reg *val)
{
        int r = kvmppc_get_one_reg_e500_tlb(vcpu, id, val);
        return r;
}

static int kvmppc_set_one_reg_e500(struct kvm_vcpu *vcpu, u64 id,
                                   union kvmppc_one_reg *val)
{
        int r = kvmppc_get_one_reg_e500_tlb(vcpu, id, val);
        return r;
}

static struct kvm_vcpu *kvmppc_core_vcpu_create_e500(struct kvm *kvm,
                                                     unsigned int id)
{
        struct kvmppc_vcpu_e500 *vcpu_e500;
        struct kvm_vcpu *vcpu;
        int err;

        vcpu_e500 = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
        if (!vcpu_e500) {
                err = -ENOMEM;
                goto out;
        }

        vcpu = &vcpu_e500->vcpu;
        err = kvm_vcpu_init(vcpu, kvm, id);
        if (err)
                goto free_vcpu;

        if (kvmppc_e500_id_table_alloc(vcpu_e500) == NULL) {
                err = -ENOMEM;
                goto uninit_vcpu;
        }

        err = kvmppc_e500_tlb_init(vcpu_e500);
        if (err)
                goto uninit_id;

        vcpu->arch.shared = (void*)__get_free_page(GFP_KERNEL|__GFP_ZERO);
        if (!vcpu->arch.shared) {
                err = -ENOMEM;
                goto uninit_tlb;
        }

        return vcpu;

uninit_tlb:
        kvmppc_e500_tlb_uninit(vcpu_e500);
uninit_id:
        kvmppc_e500_id_table_free(vcpu_e500);
uninit_vcpu:
        kvm_vcpu_uninit(vcpu);
free_vcpu:
        kmem_cache_free(kvm_vcpu_cache, vcpu_e500);
out:
        return ERR_PTR(err);
}

static void kvmppc_core_vcpu_free_e500(struct kvm_vcpu *vcpu)
{
        struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);

        free_page((unsigned long)vcpu->arch.shared);
        kvmppc_e500_tlb_uninit(vcpu_e500);
        kvmppc_e500_id_table_free(vcpu_e500);
        kvm_vcpu_uninit(vcpu);
        kmem_cache_free(kvm_vcpu_cache, vcpu_e500);
}

static int kvmppc_core_init_vm_e500(struct kvm *kvm)
{
        return 0;
}

static void kvmppc_core_destroy_vm_e500(struct kvm *kvm)
{
}

static struct kvmppc_ops kvm_ops_e500 = {
        .get_sregs = kvmppc_core_get_sregs_e500,
        .set_sregs = kvmppc_core_set_sregs_e500,
        .get_one_reg = kvmppc_get_one_reg_e500,
        .set_one_reg = kvmppc_set_one_reg_e500,
        .vcpu_load   = kvmppc_core_vcpu_load_e500,
        .vcpu_put    = kvmppc_core_vcpu_put_e500,
        .vcpu_create = kvmppc_core_vcpu_create_e500,
        .vcpu_free   = kvmppc_core_vcpu_free_e500,
        .mmu_destroy  = kvmppc_mmu_destroy_e500,
        .init_vm = kvmppc_core_init_vm_e500,
        .destroy_vm = kvmppc_core_destroy_vm_e500,
        .emulate_op = kvmppc_core_emulate_op_e500,
        .emulate_mtspr = kvmppc_core_emulate_mtspr_e500,
        .emulate_mfspr = kvmppc_core_emulate_mfspr_e500,
};

static int __init kvmppc_e500_init(void)
{
        int r, i;
        unsigned long ivor[3];
        /* Process remaining handlers above the generic first 16 */
        unsigned long *handler = &kvmppc_booke_handler_addr[16];
        unsigned long handler_len;
        unsigned long max_ivor = 0;

        r = kvmppc_core_check_processor_compat();
        if (r)
                goto err_out;

        r = kvmppc_booke_init();
        if (r)
                goto err_out;

        /* copy extra E500 exception handlers */
        ivor[0] = mfspr(SPRN_IVOR32);
        ivor[1] = mfspr(SPRN_IVOR33);
        ivor[2] = mfspr(SPRN_IVOR34);
        for (i = 0; i < 3; i++) {
                if (ivor[i] > ivor[max_ivor])
                        max_ivor = i;

                handler_len = handler[i + 1] - handler[i];
                memcpy((void *)kvmppc_booke_handlers + ivor[i],
                       (void *)handler[i], handler_len);
        }
        handler_len = handler[max_ivor + 1] - handler[max_ivor];
        flush_icache_range(kvmppc_booke_handlers, kvmppc_booke_handlers +
                           ivor[max_ivor] + handler_len);

        r = kvm_init(NULL, sizeof(struct kvmppc_vcpu_e500), 0, THIS_MODULE);
        if (r)
                goto err_out;
        kvm_ops_e500.owner = THIS_MODULE;
        kvmppc_pr_ops = &kvm_ops_e500;

err_out:
        return r;
}

static void __exit kvmppc_e500_exit(void)
{
        kvmppc_pr_ops = NULL;
        kvmppc_booke_exit();
}

module_init(kvmppc_e500_init);
module_exit(kvmppc_e500_exit);
MODULE_ALIAS_MISCDEV(KVM_MINOR);
MODULE_ALIAS("devname:kvm");