/*
 * 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.
 *
 * Copyright 2016 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>

#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>

/*
 * Supported radix tree geometry.
 * Like p9, we support either 5 or 9 bits at the first (lowest) level,
 * for a page size of 64k or 4k.
 */
static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 };

int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
                           struct kvmppc_pte *gpte, bool data, bool iswrite)
{
        struct kvm *kvm = vcpu->kvm;
        u32 pid;
        int ret, level, ps;
        __be64 prte, rpte;
        unsigned long ptbl;
        unsigned long root, pte, index;
        unsigned long rts, bits, offset;
        unsigned long gpa;
        unsigned long proc_tbl_size;

        /* Work out effective PID */
        switch (eaddr >> 62) {
        case 0:
                pid = vcpu->arch.pid;
                break;
        case 3:
                pid = 0;
                break;
        default:
                return -EINVAL;
        }
        proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12);
        if (pid * 16 >= proc_tbl_size)
                return -EINVAL;

        /* Read partition table to find root of tree for effective PID */
        ptbl = (kvm->arch.process_table & PRTB_MASK) + (pid * 16);
        ret = kvm_read_guest(kvm, ptbl, &prte, sizeof(prte));
        if (ret)
                return ret;

        root = be64_to_cpu(prte);
        rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
                ((root & RTS2_MASK) >> RTS2_SHIFT);
        bits = root & RPDS_MASK;
        root = root & RPDB_MASK;

        /* P9 DD1 interprets RTS (radix tree size) differently */
        offset = rts + 31;
        if (cpu_has_feature(CPU_FTR_POWER9_DD1))
                offset -= 3;

        /* current implementations only support 52-bit space */
        if (offset != 52)
                return -EINVAL;

        for (level = 3; level >= 0; --level) {
                if (level && bits != p9_supported_radix_bits[level])
                        return -EINVAL;
                if (level == 0 && !(bits == 5 || bits == 9))
                        return -EINVAL;
                offset -= bits;
                index = (eaddr >> offset) & ((1UL << bits) - 1);
                /* check that low bits of page table base are zero */
                if (root & ((1UL << (bits + 3)) - 1))
                        return -EINVAL;
                ret = kvm_read_guest(kvm, root + index * 8,
                                     &rpte, sizeof(rpte));
                if (ret)
                        return ret;
                pte = __be64_to_cpu(rpte);
                if (!(pte & _PAGE_PRESENT))
                        return -ENOENT;
                if (pte & _PAGE_PTE)
                        break;
                bits = pte & 0x1f;
                root = pte & 0x0fffffffffffff00ul;
        }
        /* need a leaf at lowest level; 512GB pages not supported */
        if (level < 0 || level == 3)
                return -EINVAL;

        /* offset is now log base 2 of the page size */
        gpa = pte & 0x01fffffffffff000ul;
        if (gpa & ((1ul << offset) - 1))
                return -EINVAL;
        gpa += eaddr & ((1ul << offset) - 1);
        for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps)
                if (offset == mmu_psize_defs[ps].shift)
                        break;
        gpte->page_size = ps;

        gpte->eaddr = eaddr;
        gpte->raddr = gpa;

        /* Work out permissions */
        gpte->may_read = !!(pte & _PAGE_READ);
        gpte->may_write = !!(pte & _PAGE_WRITE);
        gpte->may_execute = !!(pte & _PAGE_EXEC);
        if (kvmppc_get_msr(vcpu) & MSR_PR) {
                if (pte & _PAGE_PRIVILEGED) {
                        gpte->may_read = 0;
                        gpte->may_write = 0;
                        gpte->may_execute = 0;
                }
        } else {
                if (!(pte & _PAGE_PRIVILEGED)) {
                        /* Check AMR/IAMR to see if strict mode is in force */
                        if (vcpu->arch.amr & (1ul << 62))
                                gpte->may_read = 0;
                        if (vcpu->arch.amr & (1ul << 63))
                                gpte->may_write = 0;
                        if (vcpu->arch.iamr & (1ul << 62))
                                gpte->may_execute = 0;
                }
        }

        return 0;
}

#ifdef CONFIG_PPC_64K_PAGES
#define MMU_BASE_PSIZE  MMU_PAGE_64K
#else
#define MMU_BASE_PSIZE  MMU_PAGE_4K
#endif

static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
                                    unsigned int pshift)
{
        int psize = MMU_BASE_PSIZE;

        if (pshift >= PMD_SHIFT)
                psize = MMU_PAGE_2M;
        addr &= ~0xfffUL;
        addr |= mmu_psize_defs[psize].ap << 5;
        asm volatile("ptesync": : :"memory");
        asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1)
                     : : "r" (addr), "r" (kvm->arch.lpid) : "memory");
        asm volatile("ptesync": : :"memory");
}

unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
                                      unsigned long clr, unsigned long set,
                                      unsigned long addr, unsigned int shift)
{
        unsigned long old = 0;

        if (!(clr & _PAGE_PRESENT) && cpu_has_feature(CPU_FTR_POWER9_DD1) &&
            pte_present(*ptep)) {
                /* have to invalidate it first */
                old = __radix_pte_update(ptep, _PAGE_PRESENT, 0);
                kvmppc_radix_tlbie_page(kvm, addr, shift);
                set |= _PAGE_PRESENT;
                old &= _PAGE_PRESENT;
        }
        return __radix_pte_update(ptep, clr, set) | old;
}

void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
                             pte_t *ptep, pte_t pte)
{
        radix__set_pte_at(kvm->mm, addr, ptep, pte, 0);
}

static struct kmem_cache *kvm_pte_cache;

static pte_t *kvmppc_pte_alloc(void)
{
        return kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL);
}

static void kvmppc_pte_free(pte_t *ptep)
{
        kmem_cache_free(kvm_pte_cache, ptep);
}

static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
                             unsigned int level, unsigned long mmu_seq)
{
        pgd_t *pgd;
        pud_t *pud, *new_pud = NULL;
        pmd_t *pmd, *new_pmd = NULL;
        pte_t *ptep, *new_ptep = NULL;
        unsigned long old;
        int ret;

        /* Traverse the guest's 2nd-level tree, allocate new levels needed */
        pgd = kvm->arch.pgtable + pgd_index(gpa);
        pud = NULL;
        if (pgd_present(*pgd))
                pud = pud_offset(pgd, gpa);
        else
                new_pud = pud_alloc_one(kvm->mm, gpa);

        pmd = NULL;
        if (pud && pud_present(*pud))
                pmd = pmd_offset(pud, gpa);
        else
                new_pmd = pmd_alloc_one(kvm->mm, gpa);

        if (level == 0 && !(pmd && pmd_present(*pmd)))
                new_ptep = kvmppc_pte_alloc();

        /* Check if we might have been invalidated; let the guest retry if so */
        spin_lock(&kvm->mmu_lock);
        ret = -EAGAIN;
        if (mmu_notifier_retry(kvm, mmu_seq))
                goto out_unlock;

        /* Now traverse again under the lock and change the tree */
        ret = -ENOMEM;
        if (pgd_none(*pgd)) {
                if (!new_pud)
                        goto out_unlock;
                pgd_populate(kvm->mm, pgd, new_pud);
                new_pud = NULL;
        }
        pud = pud_offset(pgd, gpa);
        if (pud_none(*pud)) {
                if (!new_pmd)
                        goto out_unlock;
                pud_populate(kvm->mm, pud, new_pmd);
                new_pmd = NULL;
        }
        pmd = pmd_offset(pud, gpa);
        if (pmd_large(*pmd)) {
                /* Someone else has instantiated a large page here; retry */
                ret = -EAGAIN;
                goto out_unlock;
        }
        if (level == 1 && !pmd_none(*pmd)) {
                /*
                 * There's a page table page here, but we wanted
                 * to install a large page.  Tell the caller and let
                 * it try installing a normal page if it wants.
                 */
                ret = -EBUSY;
                goto out_unlock;
        }
        if (level == 0) {
                if (pmd_none(*pmd)) {
                        if (!new_ptep)
                                goto out_unlock;
                        pmd_populate(kvm->mm, pmd, new_ptep);
                        new_ptep = NULL;
                }
                ptep = pte_offset_kernel(pmd, gpa);
                if (pte_present(*ptep)) {
                        /* PTE was previously valid, so invalidate it */
                        old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT,
                                                      0, gpa, 0);
                        kvmppc_radix_tlbie_page(kvm, gpa, 0);
                        if (old & _PAGE_DIRTY)
                                mark_page_dirty(kvm, gpa >> PAGE_SHIFT);
                }
                kvmppc_radix_set_pte_at(kvm, gpa, ptep, pte);
        } else {
                kvmppc_radix_set_pte_at(kvm, gpa, pmdp_ptep(pmd), pte);
        }
        ret = 0;

 out_unlock:
        spin_unlock(&kvm->mmu_lock);
        if (new_pud)
                pud_free(kvm->mm, new_pud);
        if (new_pmd)
                pmd_free(kvm->mm, new_pmd);
        if (new_ptep)
                kvmppc_pte_free(new_ptep);
        return ret;
}

int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
                                   unsigned long ea, unsigned long dsisr)
{
        struct kvm *kvm = vcpu->kvm;
        unsigned long mmu_seq, pte_size;
        unsigned long gpa, gfn, hva, pfn;
        struct kvm_memory_slot *memslot;
        struct page *page = NULL, *pages[1];
        long ret, npages, ok;
        unsigned int writing;
        struct vm_area_struct *vma;
        unsigned long flags;
        pte_t pte, *ptep;
        unsigned long pgflags;
        unsigned int shift, level;

        /* Check for unusual errors */
        if (dsisr & DSISR_UNSUPP_MMU) {
                pr_err("KVM: Got unsupported MMU fault\n");
                return -EFAULT;
        }
        if (dsisr & DSISR_BADACCESS) {
                /* Reflect to the guest as DSI */
                pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr);
                kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
                return RESUME_GUEST;
        }

        /* Translate the logical address and get the page */
        gpa = vcpu->arch.fault_gpa & ~0xfffUL;
        gpa &= ~0xF000000000000000ul;
        gfn = gpa >> PAGE_SHIFT;
        if (!(dsisr & DSISR_PGDIRFAULT))
                gpa |= ea & 0xfff;
        memslot = gfn_to_memslot(kvm, gfn);

        /* No memslot means it's an emulated MMIO region */
        if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
                if (dsisr & (DSISR_PGDIRFAULT | DSISR_BADACCESS |
                             DSISR_SET_RC)) {
                        /*
                         * Bad address in guest page table tree, or other
                         * unusual error - reflect it to the guest as DSI.
                         */
                        kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
                        return RESUME_GUEST;
                }
                return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea,
                                              dsisr & DSISR_ISSTORE);
        }

        /* used to check for invalidations in progress */
        mmu_seq = kvm->mmu_notifier_seq;
        smp_rmb();

        writing = (dsisr & DSISR_ISSTORE) != 0;
        hva = gfn_to_hva_memslot(memslot, gfn);
        if (dsisr & DSISR_SET_RC) {
                /*
                 * Need to set an R or C bit in the 2nd-level tables;
                 * if the relevant bits aren't already set in the linux
                 * page tables, fall through to do the gup_fast to
                 * set them in the linux page tables too.
                 */
                ok = 0;
                pgflags = _PAGE_ACCESSED;
                if (writing)
                        pgflags |= _PAGE_DIRTY;
                local_irq_save(flags);
                ptep = __find_linux_pte_or_hugepte(current->mm->pgd, hva,
                                                   NULL, NULL);
                if (ptep) {
                        pte = READ_ONCE(*ptep);
                        if (pte_present(pte) &&
                            (pte_val(pte) & pgflags) == pgflags)
                                ok = 1;
                }
                local_irq_restore(flags);
                if (ok) {
                        spin_lock(&kvm->mmu_lock);
                        if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
                                spin_unlock(&kvm->mmu_lock);
                                return RESUME_GUEST;
                        }
                        ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable,
                                                        gpa, NULL, &shift);
                        if (ptep && pte_present(*ptep)) {
                                kvmppc_radix_update_pte(kvm, ptep, 0, pgflags,
                                                        gpa, shift);
                                spin_unlock(&kvm->mmu_lock);
                                return RESUME_GUEST;
                        }
                        spin_unlock(&kvm->mmu_lock);
                }
        }

        ret = -EFAULT;
        pfn = 0;
        pte_size = PAGE_SIZE;
        pgflags = _PAGE_READ | _PAGE_EXEC;
        level = 0;
        npages = get_user_pages_fast(hva, 1, writing, pages);
        if (npages < 1) {
                /* Check if it's an I/O mapping */
                down_read(&current->mm->mmap_sem);
                vma = find_vma(current->mm, hva);
                if (vma && vma->vm_start <= hva && hva < vma->vm_end &&
                    (vma->vm_flags & VM_PFNMAP)) {
                        pfn = vma->vm_pgoff +
                                ((hva - vma->vm_start) >> PAGE_SHIFT);
                        pgflags = pgprot_val(vma->vm_page_prot);
                }
                up_read(&current->mm->mmap_sem);
                if (!pfn)
                        return -EFAULT;
        } else {
                page = pages[0];
                pfn = page_to_pfn(page);
                if (PageHuge(page)) {
                        page = compound_head(page);
                        pte_size <<= compound_order(page);
                        /* See if we can insert a 2MB large-page PTE here */
                        if (pte_size >= PMD_SIZE &&
                            (gpa & PMD_MASK & PAGE_MASK) ==
                            (hva & PMD_MASK & PAGE_MASK)) {
                                level = 1;
                                pfn &= ~((PMD_SIZE >> PAGE_SHIFT) - 1);
                        }
                }
                /* See if we can provide write access */
                if (writing) {
                        /*
                         * We assume gup_fast has set dirty on the host PTE.
                         */
                        pgflags |= _PAGE_WRITE;
                } else {
                        local_irq_save(flags);
                        ptep = __find_linux_pte_or_hugepte(current->mm->pgd,
                                                        hva, NULL, NULL);
                        if (ptep && pte_write(*ptep) && pte_dirty(*ptep))
                                pgflags |= _PAGE_WRITE;
                        local_irq_restore(flags);
                }
        }

        /*
         * Compute the PTE value that we need to insert.
         */
        pgflags |= _PAGE_PRESENT | _PAGE_PTE | _PAGE_ACCESSED;
        if (pgflags & _PAGE_WRITE)
                pgflags |= _PAGE_DIRTY;
        pte = pfn_pte(pfn, __pgprot(pgflags));

        /* Allocate space in the tree and write the PTE */
        ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
        if (ret == -EBUSY) {
                /*
                 * There's already a PMD where wanted to install a large page;
                 * for now, fall back to installing a small page.
                 */
                level = 0;
                pfn |= gfn & ((PMD_SIZE >> PAGE_SHIFT) - 1);
                pte = pfn_pte(pfn, __pgprot(pgflags));
                ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
        }
        if (ret == 0 || ret == -EAGAIN)
                ret = RESUME_GUEST;

        if (page) {
                /*
                 * We drop pages[0] here, not page because page might
                 * have been set to the head page of a compound, but
                 * we have to drop the reference on the correct tail
                 * page to match the get inside gup()
                 */
                put_page(pages[0]);
        }
        return ret;
}

static void mark_pages_dirty(struct kvm *kvm, struct kvm_memory_slot *memslot,
                             unsigned long gfn, unsigned int order)
{
        unsigned long i, limit;
        unsigned long *dp;

        if (!memslot->dirty_bitmap)
                return;
        limit = 1ul << order;
        if (limit < BITS_PER_LONG) {
                for (i = 0; i < limit; ++i)
                        mark_page_dirty(kvm, gfn + i);
                return;
        }
        dp = memslot->dirty_bitmap + (gfn - memslot->base_gfn);
        limit /= BITS_PER_LONG;
        for (i = 0; i < limit; ++i)
                *dp++ = ~0ul;
}

/* Called with kvm->lock held */
int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
                    unsigned long gfn)
{
        pte_t *ptep;
        unsigned long gpa = gfn << PAGE_SHIFT;
        unsigned int shift;
        unsigned long old;

        ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
                                           NULL, &shift);
        if (ptep && pte_present(*ptep)) {
                old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
                                              gpa, shift);
                kvmppc_radix_tlbie_page(kvm, gpa, shift);
                if (old & _PAGE_DIRTY) {
                        if (!shift)
                                mark_page_dirty(kvm, gfn);
                        else
                                mark_pages_dirty(kvm, memslot,
                                                 gfn, shift - PAGE_SHIFT);
                }
        }
        return 0;                               
}

/* Called with kvm->lock held */
int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
                  unsigned long gfn)
{
        pte_t *ptep;
        unsigned long gpa = gfn << PAGE_SHIFT;
        unsigned int shift;
        int ref = 0;

        ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
                                           NULL, &shift);
        if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
                kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
                                        gpa, shift);
                /* XXX need to flush tlb here? */
                ref = 1;
        }
        return ref;
}

/* Called with kvm->lock held */
int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
                       unsigned long gfn)
{
        pte_t *ptep;
        unsigned long gpa = gfn << PAGE_SHIFT;
        unsigned int shift;
        int ref = 0;

        ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
                                           NULL, &shift);
        if (ptep && pte_present(*ptep) && pte_young(*ptep))
                ref = 1;
        return ref;
}

/* Returns the number of PAGE_SIZE pages that are dirty */
static int kvm_radix_test_clear_dirty(struct kvm *kvm,
                                struct kvm_memory_slot *memslot, int pagenum)
{
        unsigned long gfn = memslot->base_gfn + pagenum;
        unsigned long gpa = gfn << PAGE_SHIFT;
        pte_t *ptep;
        unsigned int shift;
        int ret = 0;

        ptep = __find_linux_pte_or_hugepte(kvm->arch.pgtable, gpa,
                                           NULL, &shift);
        if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
                ret = 1;
                if (shift)
                        ret = 1 << (shift - PAGE_SHIFT);
                kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0,
                                        gpa, shift);
                kvmppc_radix_tlbie_page(kvm, gpa, shift);
        }
        return ret;
}

long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm,
                        struct kvm_memory_slot *memslot, unsigned long *map)
{
        unsigned long i, j;
        unsigned long n, *p;
        int npages;

        /*
         * Radix accumulates dirty bits in the first half of the
         * memslot's dirty_bitmap area, for when pages are paged
         * out or modified by the host directly.  Pick up these
         * bits and add them to the map.
         */
        n = kvm_dirty_bitmap_bytes(memslot) / sizeof(long);
        p = memslot->dirty_bitmap;
        for (i = 0; i < n; ++i)
                map[i] |= xchg(&p[i], 0);

        for (i = 0; i < memslot->npages; i = j) {
                npages = kvm_radix_test_clear_dirty(kvm, memslot, i);

                /*
                 * Note that if npages > 0 then i must be a multiple of npages,
                 * since huge pages are only used to back the guest at guest
                 * real addresses that are a multiple of their size.
                 * Since we have at most one PTE covering any given guest
                 * real address, if npages > 1 we can skip to i + npages.
                 */
                j = i + 1;
                if (npages)
                        for (j = i; npages; ++j, --npages)
                                __set_bit_le(j, map);
        }
        return 0;
}

static void add_rmmu_ap_encoding(struct kvm_ppc_rmmu_info *info,
                                 int psize, int *indexp)
{
        if (!mmu_psize_defs[psize].shift)
                return;
        info->ap_encodings[*indexp] = mmu_psize_defs[psize].shift |
                (mmu_psize_defs[psize].ap << 29);
        ++(*indexp);
}

int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info)
{
        int i;

        if (!radix_enabled())
                return -EINVAL;
        memset(info, 0, sizeof(*info));

        /* 4k page size */
        info->geometries[0].page_shift = 12;
        info->geometries[0].level_bits[0] = 9;
        for (i = 1; i < 4; ++i)
                info->geometries[0].level_bits[i] = p9_supported_radix_bits[i];
        /* 64k page size */
        info->geometries[1].page_shift = 16;
        for (i = 0; i < 4; ++i)
                info->geometries[1].level_bits[i] = p9_supported_radix_bits[i];

        i = 0;
        add_rmmu_ap_encoding(info, MMU_PAGE_4K, &i);
        add_rmmu_ap_encoding(info, MMU_PAGE_64K, &i);
        add_rmmu_ap_encoding(info, MMU_PAGE_2M, &i);
        add_rmmu_ap_encoding(info, MMU_PAGE_1G, &i);

        return 0;
}

int kvmppc_init_vm_radix(struct kvm *kvm)
{
        kvm->arch.pgtable = pgd_alloc(kvm->mm);
        if (!kvm->arch.pgtable)
                return -ENOMEM;
        return 0;
}

void kvmppc_free_radix(struct kvm *kvm)
{
        unsigned long ig, iu, im;
        pte_t *pte;
        pmd_t *pmd;
        pud_t *pud;
        pgd_t *pgd;

        if (!kvm->arch.pgtable)
                return;
        pgd = kvm->arch.pgtable;
        for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) {
                if (!pgd_present(*pgd))
                        continue;
                pud = pud_offset(pgd, 0);
                for (iu = 0; iu < PTRS_PER_PUD; ++iu, ++pud) {
                        if (!pud_present(*pud))
                                continue;
                        pmd = pmd_offset(pud, 0);
                        for (im = 0; im < PTRS_PER_PMD; ++im, ++pmd) {
                                if (pmd_huge(*pmd)) {
                                        pmd_clear(pmd);
                                        continue;
                                }
                                if (!pmd_present(*pmd))
                                        continue;
                                pte = pte_offset_map(pmd, 0);
                                memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE);
                                kvmppc_pte_free(pte);
                                pmd_clear(pmd);
                        }
                        pmd_free(kvm->mm, pmd_offset(pud, 0));
                        pud_clear(pud);
                }
                pud_free(kvm->mm, pud_offset(pgd, 0));
                pgd_clear(pgd);
        }
        pgd_free(kvm->mm, kvm->arch.pgtable);
}

static void pte_ctor(void *addr)
{
        memset(addr, 0, PTE_TABLE_SIZE);
}

int kvmppc_radix_init(void)
{
        unsigned long size = sizeof(void *) << PTE_INDEX_SIZE;

        kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor);
        if (!kvm_pte_cache)
                return -ENOMEM;
        return 0;
}

void kvmppc_radix_exit(void)
{
        kmem_cache_destroy(kvm_pte_cache);
}