linux/arch/powerpc/kvm/book3s_64_mmu_radix.c
Paul Mackerras 70cd4c10b2 KVM: PPC: Book3S HV: Fix software walk of guest process page tables
This fixes some bugs in the code that walks the guest's page tables.
These bugs cause MMIO emulation to fail whenever the guest is in
virtial mode (MMU on), leading to the guest hanging if it tried to
access a virtio device.

The first bug was that when reading the guest's process table, we were
using the whole of arch->process_table, not just the field that contains
the process table base address.  The second bug was that the mask used
when reading the process table entry to get the radix tree base address,
RPDB_MASK, had the wrong value.

Fixes: 9e04ba69be ("KVM: PPC: Book3S HV: Add basic infrastructure for radix guests")
Fixes: e99833448c ("powerpc/mm/radix: Add partition table format & callback")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-03-01 11:53:45 +11:00

718 lines
18 KiB
C

/*
* 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);
}