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linux/arch/x86/kvm/mmu.c
Joerg Roedel 02f59dc9f1 KVM: MMU: Introduce init_kvm_nested_mmu() 
This patch introduces the init_kvm_nested_mmu() function
which is used to re-initialize the nested mmu when the l2
guest changes its paging mode.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-24 10:52:39 +02:00

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/*
* Kernel-based Virtual Machine driver for Linux
*
* This module enables machines with Intel VT-x extensions to run virtual
* machines without emulation or binary translation.
*
* MMU support
*
* Copyright (C) 2006 Qumranet, Inc.
* Copyright 2010 Red Hat, Inc. and/or its affilates.
*
* Authors:
* Yaniv Kamay <yaniv@qumranet.com>
* Avi Kivity <avi@qumranet.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "mmu.h"
#include "x86.h"
#include "kvm_cache_regs.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/swap.h>
#include <linux/hugetlb.h>
#include <linux/compiler.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/cmpxchg.h>
#include <asm/io.h>
#include <asm/vmx.h>
/*
* When setting this variable to true it enables Two-Dimensional-Paging
* where the hardware walks 2 page tables:
* 1. the guest-virtual to guest-physical
* 2. while doing 1. it walks guest-physical to host-physical
* If the hardware supports that we don't need to do shadow paging.
*/
bool tdp_enabled = false;
enum {
AUDIT_PRE_PAGE_FAULT,
AUDIT_POST_PAGE_FAULT,
AUDIT_PRE_PTE_WRITE,
AUDIT_POST_PTE_WRITE
};
char *audit_point_name[] = {
"pre page fault",
"post page fault",
"pre pte write",
"post pte write"
};
#undef MMU_DEBUG
#ifdef MMU_DEBUG
#define pgprintk(x...) do { if (dbg) printk(x); } while (0)
#define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
#else
#define pgprintk(x...) do { } while (0)
#define rmap_printk(x...) do { } while (0)
#endif
#ifdef MMU_DEBUG
static int dbg = 0;
module_param(dbg, bool, 0644);
#endif
static int oos_shadow = 1;
module_param(oos_shadow, bool, 0644);
#ifndef MMU_DEBUG
#define ASSERT(x) do { } while (0)
#else
#define ASSERT(x) \
if (!(x)) { \
printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
__FILE__, __LINE__, #x); \
}
#endif
#define PTE_PREFETCH_NUM 8
#define PT_FIRST_AVAIL_BITS_SHIFT 9
#define PT64_SECOND_AVAIL_BITS_SHIFT 52
#define PT64_LEVEL_BITS 9
#define PT64_LEVEL_SHIFT(level) \
(PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
#define PT64_LEVEL_MASK(level) \
(((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
#define PT64_INDEX(address, level)\
(((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
#define PT32_LEVEL_BITS 10
#define PT32_LEVEL_SHIFT(level) \
(PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
#define PT32_LEVEL_MASK(level) \
(((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
#define PT32_LVL_OFFSET_MASK(level) \
(PT32_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
* PT32_LEVEL_BITS))) - 1))
#define PT32_INDEX(address, level)\
(((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
#define PT64_DIR_BASE_ADDR_MASK \
(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
#define PT64_LVL_ADDR_MASK(level) \
(PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
* PT64_LEVEL_BITS))) - 1))
#define PT64_LVL_OFFSET_MASK(level) \
(PT64_BASE_ADDR_MASK & ((1ULL << (PAGE_SHIFT + (((level) - 1) \
* PT64_LEVEL_BITS))) - 1))
#define PT32_BASE_ADDR_MASK PAGE_MASK
#define PT32_DIR_BASE_ADDR_MASK \
(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
#define PT32_LVL_ADDR_MASK(level) \
(PAGE_MASK & ~((1ULL << (PAGE_SHIFT + (((level) - 1) \
* PT32_LEVEL_BITS))) - 1))
#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
| PT64_NX_MASK)
#define RMAP_EXT 4
#define ACC_EXEC_MASK 1
#define ACC_WRITE_MASK PT_WRITABLE_MASK
#define ACC_USER_MASK PT_USER_MASK
#define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
#include <trace/events/kvm.h>
#define CREATE_TRACE_POINTS
#include "mmutrace.h"
#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
struct kvm_rmap_desc {
u64 *sptes[RMAP_EXT];
struct kvm_rmap_desc *more;
};
struct kvm_shadow_walk_iterator {
u64 addr;
hpa_t shadow_addr;
int level;
u64 *sptep;
unsigned index;
};
#define for_each_shadow_entry(_vcpu, _addr, _walker) \
for (shadow_walk_init(&(_walker), _vcpu, _addr); \
shadow_walk_okay(&(_walker)); \
shadow_walk_next(&(_walker)))
typedef void (*mmu_parent_walk_fn) (struct kvm_mmu_page *sp, u64 *spte);
static struct kmem_cache *pte_chain_cache;
static struct kmem_cache *rmap_desc_cache;
static struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;
static u64 __read_mostly shadow_trap_nonpresent_pte;
static u64 __read_mostly shadow_notrap_nonpresent_pte;
static u64 __read_mostly shadow_base_present_pte;
static u64 __read_mostly shadow_nx_mask;
static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
static u64 __read_mostly shadow_user_mask;
static u64 __read_mostly shadow_accessed_mask;
static u64 __read_mostly shadow_dirty_mask;
static inline u64 rsvd_bits(int s, int e)
{
return ((1ULL << (e - s + 1)) - 1) << s;
}
void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
{
shadow_trap_nonpresent_pte = trap_pte;
shadow_notrap_nonpresent_pte = notrap_pte;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
void kvm_mmu_set_base_ptes(u64 base_pte)
{
shadow_base_present_pte = base_pte;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
u64 dirty_mask, u64 nx_mask, u64 x_mask)
{
shadow_user_mask = user_mask;
shadow_accessed_mask = accessed_mask;
shadow_dirty_mask = dirty_mask;
shadow_nx_mask = nx_mask;
shadow_x_mask = x_mask;
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
static bool is_write_protection(struct kvm_vcpu *vcpu)
{
return kvm_read_cr0_bits(vcpu, X86_CR0_WP);
}
static int is_cpuid_PSE36(void)
{
return 1;
}
static int is_nx(struct kvm_vcpu *vcpu)
{
return vcpu->arch.efer & EFER_NX;
}
static int is_shadow_present_pte(u64 pte)
{
return pte != shadow_trap_nonpresent_pte
&& pte != shadow_notrap_nonpresent_pte;
}
static int is_large_pte(u64 pte)
{
return pte & PT_PAGE_SIZE_MASK;
}
static int is_writable_pte(unsigned long pte)
{
return pte & PT_WRITABLE_MASK;
}
static int is_dirty_gpte(unsigned long pte)
{
return pte & PT_DIRTY_MASK;
}
static int is_rmap_spte(u64 pte)
{
return is_shadow_present_pte(pte);
}
static int is_last_spte(u64 pte, int level)
{
if (level == PT_PAGE_TABLE_LEVEL)
return 1;
if (is_large_pte(pte))
return 1;
return 0;
}
static pfn_t spte_to_pfn(u64 pte)
{
return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
}
static gfn_t pse36_gfn_delta(u32 gpte)
{
int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
return (gpte & PT32_DIR_PSE36_MASK) << shift;
}
static void __set_spte(u64 *sptep, u64 spte)
{
set_64bit(sptep, spte);
}
static u64 __xchg_spte(u64 *sptep, u64 new_spte)
{
#ifdef CONFIG_X86_64
return xchg(sptep, new_spte);
#else
u64 old_spte;
do {
old_spte = *sptep;
} while (cmpxchg64(sptep, old_spte, new_spte) != old_spte);
return old_spte;
#endif
}
static bool spte_has_volatile_bits(u64 spte)
{
if (!shadow_accessed_mask)
return false;
if (!is_shadow_present_pte(spte))
return false;
if ((spte & shadow_accessed_mask) &&
(!is_writable_pte(spte) || (spte & shadow_dirty_mask)))
return false;
return true;
}
static bool spte_is_bit_cleared(u64 old_spte, u64 new_spte, u64 bit_mask)
{
return (old_spte & bit_mask) && !(new_spte & bit_mask);
}
static void update_spte(u64 *sptep, u64 new_spte)
{
u64 mask, old_spte = *sptep;
WARN_ON(!is_rmap_spte(new_spte));
new_spte |= old_spte & shadow_dirty_mask;
mask = shadow_accessed_mask;
if (is_writable_pte(old_spte))
mask |= shadow_dirty_mask;
if (!spte_has_volatile_bits(old_spte) || (new_spte & mask) == mask)
__set_spte(sptep, new_spte);
else
old_spte = __xchg_spte(sptep, new_spte);
if (!shadow_accessed_mask)
return;
if (spte_is_bit_cleared(old_spte, new_spte, shadow_accessed_mask))
kvm_set_pfn_accessed(spte_to_pfn(old_spte));
if (spte_is_bit_cleared(old_spte, new_spte, shadow_dirty_mask))
kvm_set_pfn_dirty(spte_to_pfn(old_spte));
}
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
struct kmem_cache *base_cache, int min)
{
void *obj;
if (cache->nobjs >= min)
return 0;
while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
if (!obj)
return -ENOMEM;
cache->objects[cache->nobjs++] = obj;
}
return 0;
}
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
struct kmem_cache *cache)
{
while (mc->nobjs)
kmem_cache_free(cache, mc->objects[--mc->nobjs]);
}
static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
int min)
{
struct page *page;
if (cache->nobjs >= min)
return 0;
while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
page = alloc_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
cache->objects[cache->nobjs++] = page_address(page);
}
return 0;
}
static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
{
while (mc->nobjs)
free_page((unsigned long)mc->objects[--mc->nobjs]);
}
static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
{
int r;
r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
pte_chain_cache, 4);
if (r)
goto out;
r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
rmap_desc_cache, 4 + PTE_PREFETCH_NUM);
if (r)
goto out;
r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
if (r)
goto out;
r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
mmu_page_header_cache, 4);
out:
return r;
}
static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache, pte_chain_cache);
mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache, rmap_desc_cache);
mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
mmu_page_header_cache);
}
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
size_t size)
{
void *p;
BUG_ON(!mc->nobjs);
p = mc->objects[--mc->nobjs];
return p;
}
static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
{
return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
sizeof(struct kvm_pte_chain));
}
static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
{
kmem_cache_free(pte_chain_cache, pc);
}
static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
{
return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
sizeof(struct kvm_rmap_desc));
}
static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
{
kmem_cache_free(rmap_desc_cache, rd);
}
static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
{
if (!sp->role.direct)
return sp->gfns[index];
return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS));
}
static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
{
if (sp->role.direct)
BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index));
else
sp->gfns[index] = gfn;
}
/*
* Return the pointer to the largepage write count for a given
* gfn, handling slots that are not large page aligned.
*/
static int *slot_largepage_idx(gfn_t gfn,
struct kvm_memory_slot *slot,
int level)
{
unsigned long idx;
idx = (gfn >> KVM_HPAGE_GFN_SHIFT(level)) -
(slot->base_gfn >> KVM_HPAGE_GFN_SHIFT(level));
return &slot->lpage_info[level - 2][idx].write_count;
}
static void account_shadowed(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
int *write_count;
int i;
slot = gfn_to_memslot(kvm, gfn);
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
write_count = slot_largepage_idx(gfn, slot, i);
*write_count += 1;
}
}
static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
int *write_count;
int i;
slot = gfn_to_memslot(kvm, gfn);
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
write_count = slot_largepage_idx(gfn, slot, i);
*write_count -= 1;
WARN_ON(*write_count < 0);
}
}
static int has_wrprotected_page(struct kvm *kvm,
gfn_t gfn,
int level)
{
struct kvm_memory_slot *slot;
int *largepage_idx;
slot = gfn_to_memslot(kvm, gfn);
if (slot) {
largepage_idx = slot_largepage_idx(gfn, slot, level);
return *largepage_idx;
}
return 1;
}
static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
{
unsigned long page_size;
int i, ret = 0;
page_size = kvm_host_page_size(kvm, gfn);
for (i = PT_PAGE_TABLE_LEVEL;
i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
if (page_size >= KVM_HPAGE_SIZE(i))
ret = i;
else
break;
}
return ret;
}
static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
struct kvm_memory_slot *slot;
int host_level, level, max_level;
slot = gfn_to_memslot(vcpu->kvm, large_gfn);
if (slot && slot->dirty_bitmap)
return PT_PAGE_TABLE_LEVEL;
host_level = host_mapping_level(vcpu->kvm, large_gfn);
if (host_level == PT_PAGE_TABLE_LEVEL)
return host_level;
max_level = kvm_x86_ops->get_lpage_level() < host_level ?
kvm_x86_ops->get_lpage_level() : host_level;
for (level = PT_DIRECTORY_LEVEL; level <= max_level; ++level)
if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
break;
return level - 1;
}
/*
* Take gfn and return the reverse mapping to it.
*/
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
{
struct kvm_memory_slot *slot;
unsigned long idx;
slot = gfn_to_memslot(kvm, gfn);
if (likely(level == PT_PAGE_TABLE_LEVEL))
return &slot->rmap[gfn - slot->base_gfn];
idx = (gfn >> KVM_HPAGE_GFN_SHIFT(level)) -
(slot->base_gfn >> KVM_HPAGE_GFN_SHIFT(level));
return &slot->lpage_info[level - 2][idx].rmap_pde;
}
/*
* Reverse mapping data structures:
*
* If rmapp bit zero is zero, then rmapp point to the shadw page table entry
* that points to page_address(page).
*
* If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
* containing more mappings.
*
* Returns the number of rmap entries before the spte was added or zero if
* the spte was not added.
*
*/
static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
{
struct kvm_mmu_page *sp;
struct kvm_rmap_desc *desc;
unsigned long *rmapp;
int i, count = 0;
if (!is_rmap_spte(*spte))
return count;
sp = page_header(__pa(spte));
kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
if (!*rmapp) {
rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
*rmapp = (unsigned long)spte;
} else if (!(*rmapp & 1)) {
rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
desc = mmu_alloc_rmap_desc(vcpu);
desc->sptes[0] = (u64 *)*rmapp;
desc->sptes[1] = spte;
*rmapp = (unsigned long)desc | 1;
} else {
rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
while (desc->sptes[RMAP_EXT-1] && desc->more) {
desc = desc->more;
count += RMAP_EXT;
}
if (desc->sptes[RMAP_EXT-1]) {
desc->more = mmu_alloc_rmap_desc(vcpu);
desc = desc->more;
}
for (i = 0; desc->sptes[i]; ++i)
;
desc->sptes[i] = spte;
}
return count;
}
static void rmap_desc_remove_entry(unsigned long *rmapp,
struct kvm_rmap_desc *desc,
int i,
struct kvm_rmap_desc *prev_desc)
{
int j;
for (j = RMAP_EXT - 1; !desc->sptes[j] && j > i; --j)
;
desc->sptes[i] = desc->sptes[j];
desc->sptes[j] = NULL;
if (j != 0)
return;
if (!prev_desc && !desc->more)
*rmapp = (unsigned long)desc->sptes[0];
else
if (prev_desc)
prev_desc->more = desc->more;
else
*rmapp = (unsigned long)desc->more | 1;
mmu_free_rmap_desc(desc);
}
static void rmap_remove(struct kvm *kvm, u64 *spte)
{
struct kvm_rmap_desc *desc;
struct kvm_rmap_desc *prev_desc;
struct kvm_mmu_page *sp;
gfn_t gfn;
unsigned long *rmapp;
int i;
sp = page_header(__pa(spte));
gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
rmapp = gfn_to_rmap(kvm, gfn, sp->role.level);
if (!*rmapp) {
printk(KERN_ERR "rmap_remove: %p 0->BUG\n", spte);
BUG();
} else if (!(*rmapp & 1)) {
rmap_printk("rmap_remove: %p 1->0\n", spte);
if ((u64 *)*rmapp != spte) {
printk(KERN_ERR "rmap_remove: %p 1->BUG\n", spte);
BUG();
}
*rmapp = 0;
} else {
rmap_printk("rmap_remove: %p many->many\n", spte);
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
prev_desc = NULL;
while (desc) {
for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i)
if (desc->sptes[i] == spte) {
rmap_desc_remove_entry(rmapp,
desc, i,
prev_desc);
return;
}
prev_desc = desc;
desc = desc->more;
}
pr_err("rmap_remove: %p many->many\n", spte);
BUG();
}
}
static void set_spte_track_bits(u64 *sptep, u64 new_spte)
{
pfn_t pfn;
u64 old_spte = *sptep;
if (!spte_has_volatile_bits(old_spte))
__set_spte(sptep, new_spte);
else
old_spte = __xchg_spte(sptep, new_spte);
if (!is_rmap_spte(old_spte))
return;
pfn = spte_to_pfn(old_spte);
if (!shadow_accessed_mask || old_spte & shadow_accessed_mask)
kvm_set_pfn_accessed(pfn);
if (!shadow_dirty_mask || (old_spte & shadow_dirty_mask))
kvm_set_pfn_dirty(pfn);
}
static void drop_spte(struct kvm *kvm, u64 *sptep, u64 new_spte)
{
set_spte_track_bits(sptep, new_spte);
rmap_remove(kvm, sptep);
}
static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
{
struct kvm_rmap_desc *desc;
u64 *prev_spte;
int i;
if (!*rmapp)
return NULL;
else if (!(*rmapp & 1)) {
if (!spte)
return (u64 *)*rmapp;
return NULL;
}
desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
prev_spte = NULL;
while (desc) {
for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i) {
if (prev_spte == spte)
return desc->sptes[i];
prev_spte = desc->sptes[i];
}
desc = desc->more;
}
return NULL;
}
static int rmap_write_protect(struct kvm *kvm, u64 gfn)
{
unsigned long *rmapp;
u64 *spte;
int i, write_protected = 0;
rmapp = gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!spte);
BUG_ON(!(*spte & PT_PRESENT_MASK));
rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
if (is_writable_pte(*spte)) {
update_spte(spte, *spte & ~PT_WRITABLE_MASK);
write_protected = 1;
}
spte = rmap_next(kvm, rmapp, spte);
}
/* check for huge page mappings */
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
rmapp = gfn_to_rmap(kvm, gfn, i);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!spte);
BUG_ON(!(*spte & PT_PRESENT_MASK));
BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
if (is_writable_pte(*spte)) {
drop_spte(kvm, spte,
shadow_trap_nonpresent_pte);
--kvm->stat.lpages;
spte = NULL;
write_protected = 1;
}
spte = rmap_next(kvm, rmapp, spte);
}
}
return write_protected;
}
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *spte;
int need_tlb_flush = 0;
while ((spte = rmap_next(kvm, rmapp, NULL))) {
BUG_ON(!(*spte & PT_PRESENT_MASK));
rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
drop_spte(kvm, spte, shadow_trap_nonpresent_pte);
need_tlb_flush = 1;
}
return need_tlb_flush;
}
static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
int need_flush = 0;
u64 *spte, new_spte;
pte_t *ptep = (pte_t *)data;
pfn_t new_pfn;
WARN_ON(pte_huge(*ptep));
new_pfn = pte_pfn(*ptep);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!is_shadow_present_pte(*spte));
rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", spte, *spte);
need_flush = 1;
if (pte_write(*ptep)) {
drop_spte(kvm, spte, shadow_trap_nonpresent_pte);
spte = rmap_next(kvm, rmapp, NULL);
} else {
new_spte = *spte &~ (PT64_BASE_ADDR_MASK);
new_spte |= (u64)new_pfn << PAGE_SHIFT;
new_spte &= ~PT_WRITABLE_MASK;
new_spte &= ~SPTE_HOST_WRITEABLE;
new_spte &= ~shadow_accessed_mask;
set_spte_track_bits(spte, new_spte);
spte = rmap_next(kvm, rmapp, spte);
}
}
if (need_flush)
kvm_flush_remote_tlbs(kvm);
return 0;
}
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
unsigned long data,
int (*handler)(struct kvm *kvm, unsigned long *rmapp,
unsigned long data))
{
int i, j;
int ret;
int retval = 0;
struct kvm_memslots *slots;
slots = kvm_memslots(kvm);
for (i = 0; i < slots->nmemslots; i++) {
struct kvm_memory_slot *memslot = &slots->memslots[i];
unsigned long start = memslot->userspace_addr;
unsigned long end;
end = start + (memslot->npages << PAGE_SHIFT);
if (hva >= start && hva < end) {
gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
ret = handler(kvm, &memslot->rmap[gfn_offset], data);
for (j = 0; j < KVM_NR_PAGE_SIZES - 1; ++j) {
unsigned long idx;
int sh;
sh = KVM_HPAGE_GFN_SHIFT(PT_DIRECTORY_LEVEL+j);
idx = ((memslot->base_gfn+gfn_offset) >> sh) -
(memslot->base_gfn >> sh);
ret |= handler(kvm,
&memslot->lpage_info[j][idx].rmap_pde,
data);
}
trace_kvm_age_page(hva, memslot, ret);
retval |= ret;
}
}
return retval;
}
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
}
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);
}
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *spte;
int young = 0;
/*
* Emulate the accessed bit for EPT, by checking if this page has
* an EPT mapping, and clearing it if it does. On the next access,
* a new EPT mapping will be established.
* This has some overhead, but not as much as the cost of swapping
* out actively used pages or breaking up actively used hugepages.
*/
if (!shadow_accessed_mask)
return kvm_unmap_rmapp(kvm, rmapp, data);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
int _young;
u64 _spte = *spte;
BUG_ON(!(_spte & PT_PRESENT_MASK));
_young = _spte & PT_ACCESSED_MASK;
if (_young) {
young = 1;
clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
}
spte = rmap_next(kvm, rmapp, spte);
}
return young;
}
#define RMAP_RECYCLE_THRESHOLD 1000
static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
{
unsigned long *rmapp;
struct kvm_mmu_page *sp;
sp = page_header(__pa(spte));
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);
kvm_flush_remote_tlbs(vcpu->kvm);
}
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_handle_hva(kvm, hva, 0, kvm_age_rmapp);
}
#ifdef MMU_DEBUG
static int is_empty_shadow_page(u64 *spt)
{
u64 *pos;
u64 *end;
for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
if (is_shadow_present_pte(*pos)) {
printk(KERN_ERR "%s: %p %llx\n", __func__,
pos, *pos);
return 0;
}
return 1;
}
#endif
/*
* This value is the sum of all of the kvm instances's
* kvm->arch.n_used_mmu_pages values. We need a global,
* aggregate version in order to make the slab shrinker
* faster
*/
static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
{
kvm->arch.n_used_mmu_pages += nr;
percpu_counter_add(&kvm_total_used_mmu_pages, nr);
}
static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
ASSERT(is_empty_shadow_page(sp->spt));
hlist_del(&sp->hash_link);
list_del(&sp->link);
__free_page(virt_to_page(sp->spt));
if (!sp->role.direct)
__free_page(virt_to_page(sp->gfns));
kmem_cache_free(mmu_page_header_cache, sp);
kvm_mod_used_mmu_pages(kvm, -1);
}
static unsigned kvm_page_table_hashfn(gfn_t gfn)
{
return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
}
static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
u64 *parent_pte, int direct)
{
struct kvm_mmu_page *sp;
sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
if (!direct)
sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache,
PAGE_SIZE);
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
sp->multimapped = 0;
sp->parent_pte = parent_pte;
kvm_mod_used_mmu_pages(vcpu->kvm, +1);
return sp;
}
static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp, u64 *parent_pte)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
int i;
if (!parent_pte)
return;
if (!sp->multimapped) {
u64 *old = sp->parent_pte;
if (!old) {
sp->parent_pte = parent_pte;
return;
}
sp->multimapped = 1;
pte_chain = mmu_alloc_pte_chain(vcpu);
INIT_HLIST_HEAD(&sp->parent_ptes);
hlist_add_head(&pte_chain->link, &sp->parent_ptes);
pte_chain->parent_ptes[0] = old;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
continue;
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
if (!pte_chain->parent_ptes[i]) {
pte_chain->parent_ptes[i] = parent_pte;
return;
}
}
pte_chain = mmu_alloc_pte_chain(vcpu);
BUG_ON(!pte_chain);
hlist_add_head(&pte_chain->link, &sp->parent_ptes);
pte_chain->parent_ptes[0] = parent_pte;
}
static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
u64 *parent_pte)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
int i;
if (!sp->multimapped) {
BUG_ON(sp->parent_pte != parent_pte);
sp->parent_pte = NULL;
return;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
if (!pte_chain->parent_ptes[i])
break;
if (pte_chain->parent_ptes[i] != parent_pte)
continue;
while (i + 1 < NR_PTE_CHAIN_ENTRIES
&& pte_chain->parent_ptes[i + 1]) {
pte_chain->parent_ptes[i]
= pte_chain->parent_ptes[i + 1];
++i;
}
pte_chain->parent_ptes[i] = NULL;
if (i == 0) {
hlist_del(&pte_chain->link);
mmu_free_pte_chain(pte_chain);
if (hlist_empty(&sp->parent_ptes)) {
sp->multimapped = 0;
sp->parent_pte = NULL;
}
}
return;
}
BUG();
}
static void mmu_parent_walk(struct kvm_mmu_page *sp, mmu_parent_walk_fn fn)
{
struct kvm_pte_chain *pte_chain;
struct hlist_node *node;
struct kvm_mmu_page *parent_sp;
int i;
if (!sp->multimapped && sp->parent_pte) {
parent_sp = page_header(__pa(sp->parent_pte));
fn(parent_sp, sp->parent_pte);
return;
}
hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
u64 *spte = pte_chain->parent_ptes[i];
if (!spte)
break;
parent_sp = page_header(__pa(spte));
fn(parent_sp, spte);
}
}
static void mark_unsync(struct kvm_mmu_page *sp, u64 *spte);
static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
{
mmu_parent_walk(sp, mark_unsync);
}
static void mark_unsync(struct kvm_mmu_page *sp, u64 *spte)
{
unsigned int index;
index = spte - sp->spt;
if (__test_and_set_bit(index, sp->unsync_child_bitmap))
return;
if (sp->unsync_children++)
return;
kvm_mmu_mark_parents_unsync(sp);
}
static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp)
{
int i;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
sp->spt[i] = shadow_trap_nonpresent_pte;
}
static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp, bool clear_unsync)
{
return 1;
}
static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
}
#define KVM_PAGE_ARRAY_NR 16
struct kvm_mmu_pages {
struct mmu_page_and_offset {
struct kvm_mmu_page *sp;
unsigned int idx;
} page[KVM_PAGE_ARRAY_NR];
unsigned int nr;
};
#define for_each_unsync_children(bitmap, idx) \
for (idx = find_first_bit(bitmap, 512); \
idx < 512; \
idx = find_next_bit(bitmap, 512, idx+1))
static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
int idx)
{
int i;
if (sp->unsync)
for (i=0; i < pvec->nr; i++)
if (pvec->page[i].sp == sp)
return 0;
pvec->page[pvec->nr].sp = sp;
pvec->page[pvec->nr].idx = idx;
pvec->nr++;
return (pvec->nr == KVM_PAGE_ARRAY_NR);
}
static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
struct kvm_mmu_pages *pvec)
{
int i, ret, nr_unsync_leaf = 0;
for_each_unsync_children(sp->unsync_child_bitmap, i) {
struct kvm_mmu_page *child;
u64 ent = sp->spt[i];
if (!is_shadow_present_pte(ent) || is_large_pte(ent))
goto clear_child_bitmap;
child = page_header(ent & PT64_BASE_ADDR_MASK);
if (child->unsync_children) {
if (mmu_pages_add(pvec, child, i))
return -ENOSPC;
ret = __mmu_unsync_walk(child, pvec);
if (!ret)
goto clear_child_bitmap;
else if (ret > 0)
nr_unsync_leaf += ret;
else
return ret;
} else if (child->unsync) {
nr_unsync_leaf++;
if (mmu_pages_add(pvec, child, i))
return -ENOSPC;
} else
goto clear_child_bitmap;
continue;
clear_child_bitmap:
__clear_bit(i, sp->unsync_child_bitmap);
sp->unsync_children--;
WARN_ON((int)sp->unsync_children < 0);
}
return nr_unsync_leaf;
}
static int mmu_unsync_walk(struct kvm_mmu_page *sp,
struct kvm_mmu_pages *pvec)
{
if (!sp->unsync_children)
return 0;
mmu_pages_add(pvec, sp, 0);
return __mmu_unsync_walk(sp, pvec);
}
static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
WARN_ON(!sp->unsync);
trace_kvm_mmu_sync_page(sp);
sp->unsync = 0;
--kvm->stat.mmu_unsync;
}
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
struct list_head *invalid_list);
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
struct list_head *invalid_list);
#define for_each_gfn_sp(kvm, sp, gfn, pos) \
hlist_for_each_entry(sp, pos, \
&(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link) \
if ((sp)->gfn != (gfn)) {} else
#define for_each_gfn_indirect_valid_sp(kvm, sp, gfn, pos) \
hlist_for_each_entry(sp, pos, \
&(kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)], hash_link) \
if ((sp)->gfn != (gfn) || (sp)->role.direct || \
(sp)->role.invalid) {} else
/* @sp->gfn should be write-protected at the call site */
static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
struct list_head *invalid_list, bool clear_unsync)
{
if (sp->role.cr4_pae != !!is_pae(vcpu)) {
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
return 1;
}
if (clear_unsync)
kvm_unlink_unsync_page(vcpu->kvm, sp);
if (vcpu->arch.mmu.sync_page(vcpu, sp, clear_unsync)) {
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);
return 1;
}
kvm_mmu_flush_tlb(vcpu);
return 0;
}
static int kvm_sync_page_transient(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp)
{
LIST_HEAD(invalid_list);
int ret;
ret = __kvm_sync_page(vcpu, sp, &invalid_list, false);
if (ret)
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
return ret;
}
static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
struct list_head *invalid_list)
{
return __kvm_sync_page(vcpu, sp, invalid_list, true);
}
/* @gfn should be write-protected at the call site */
static void kvm_sync_pages(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct kvm_mmu_page *s;
struct hlist_node *node;
LIST_HEAD(invalid_list);
bool flush = false;
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
if (!s->unsync)
continue;
WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
if ((s->role.cr4_pae != !!is_pae(vcpu)) ||
(vcpu->arch.mmu.sync_page(vcpu, s, true))) {
kvm_mmu_prepare_zap_page(vcpu->kvm, s, &invalid_list);
continue;
}
kvm_unlink_unsync_page(vcpu->kvm, s);
flush = true;
}
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
if (flush)
kvm_mmu_flush_tlb(vcpu);
}
struct mmu_page_path {
struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
unsigned int idx[PT64_ROOT_LEVEL-1];
};
#define for_each_sp(pvec, sp, parents, i) \
for (i = mmu_pages_next(&pvec, &parents, -1), \
sp = pvec.page[i].sp; \
i < pvec.nr && ({ sp = pvec.page[i].sp; 1;}); \
i = mmu_pages_next(&pvec, &parents, i))
static int mmu_pages_next(struct kvm_mmu_pages *pvec,
struct mmu_page_path *parents,
int i)
{
int n;
for (n = i+1; n < pvec->nr; n++) {
struct kvm_mmu_page *sp = pvec->page[n].sp;
if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
parents->idx[0] = pvec->page[n].idx;
return n;
}
parents->parent[sp->role.level-2] = sp;
parents->idx[sp->role.level-1] = pvec->page[n].idx;
}
return n;
}
static void mmu_pages_clear_parents(struct mmu_page_path *parents)
{
struct kvm_mmu_page *sp;
unsigned int level = 0;
do {
unsigned int idx = parents->idx[level];
sp = parents->parent[level];
if (!sp)
return;
--sp->unsync_children;
WARN_ON((int)sp->unsync_children < 0);
__clear_bit(idx, sp->unsync_child_bitmap);
level++;
} while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
}
static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
struct mmu_page_path *parents,
struct kvm_mmu_pages *pvec)
{
parents->parent[parent->role.level-1] = NULL;
pvec->nr = 0;
}
static void mmu_sync_children(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *parent)
{
int i;
struct kvm_mmu_page *sp;
struct mmu_page_path parents;
struct kvm_mmu_pages pages;
LIST_HEAD(invalid_list);
kvm_mmu_pages_init(parent, &parents, &pages);
while (mmu_unsync_walk(parent, &pages)) {
int protected = 0;
for_each_sp(pages, sp, parents, i)
protected |= rmap_write_protect(vcpu->kvm, sp->gfn);
if (protected)
kvm_flush_remote_tlbs(vcpu->kvm);
for_each_sp(pages, sp, parents, i) {
kvm_sync_page(vcpu, sp, &invalid_list);
mmu_pages_clear_parents(&parents);
}
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
cond_resched_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_pages_init(parent, &parents, &pages);
}
}
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
gfn_t gfn,
gva_t gaddr,
unsigned level,
int direct,
unsigned access,
u64 *parent_pte)
{
union kvm_mmu_page_role role;
unsigned quadrant;
struct kvm_mmu_page *sp;
struct hlist_node *node;
bool need_sync = false;
role = vcpu->arch.mmu.base_role;
role.level = level;
role.direct = direct;
if (role.direct)
role.cr4_pae = 0;
role.access = access;
if (!vcpu->arch.mmu.direct_map
&& vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
role.quadrant = quadrant;
}
for_each_gfn_sp(vcpu->kvm, sp, gfn, node) {
if (!need_sync && sp->unsync)
need_sync = true;
if (sp->role.word != role.word)
continue;
if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
break;
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
if (sp->unsync_children) {
kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
kvm_mmu_mark_parents_unsync(sp);
} else if (sp->unsync)
kvm_mmu_mark_parents_unsync(sp);
trace_kvm_mmu_get_page(sp, false);
return sp;
}
++vcpu->kvm->stat.mmu_cache_miss;
sp = kvm_mmu_alloc_page(vcpu, parent_pte, direct);
if (!sp)
return sp;
sp->gfn = gfn;
sp->role = role;
hlist_add_head(&sp->hash_link,
&vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]);
if (!direct) {
if (rmap_write_protect(vcpu->kvm, gfn))
kvm_flush_remote_tlbs(vcpu->kvm);
if (level > PT_PAGE_TABLE_LEVEL && need_sync)
kvm_sync_pages(vcpu, gfn);
account_shadowed(vcpu->kvm, gfn);
}
if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
vcpu->arch.mmu.prefetch_page(vcpu, sp);
else
nonpaging_prefetch_page(vcpu, sp);
trace_kvm_mmu_get_page(sp, true);
return sp;
}
static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
struct kvm_vcpu *vcpu, u64 addr)
{
iterator->addr = addr;
iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
iterator->level = vcpu->arch.mmu.shadow_root_level;
if (iterator->level == PT32E_ROOT_LEVEL) {
iterator->shadow_addr
= vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
--iterator->level;
if (!iterator->shadow_addr)
iterator->level = 0;
}
}
static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
{
if (iterator->level < PT_PAGE_TABLE_LEVEL)
return false;
if (iterator->level == PT_PAGE_TABLE_LEVEL)
if (is_large_pte(*iterator->sptep))
return false;
iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
return true;
}
static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
{
iterator->shadow_addr = *iterator->sptep & PT64_BASE_ADDR_MASK;
--iterator->level;
}
static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
{
u64 spte;
spte = __pa(sp->spt)
| PT_PRESENT_MASK | PT_ACCESSED_MASK
| PT_WRITABLE_MASK | PT_USER_MASK;
__set_spte(sptep, spte);
}
static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep)
{
if (is_large_pte(*sptep)) {
drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
kvm_flush_remote_tlbs(vcpu->kvm);
}
}
static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned direct_access)
{
if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep)) {
struct kvm_mmu_page *child;
/*
* For the direct sp, if the guest pte's dirty bit
* changed form clean to dirty, it will corrupt the
* sp's access: allow writable in the read-only sp,
* so we should update the spte at this point to get
* a new sp with the correct access.
*/
child = page_header(*sptep & PT64_BASE_ADDR_MASK);
if (child->role.access == direct_access)
return;
mmu_page_remove_parent_pte(child, sptep);
__set_spte(sptep, shadow_trap_nonpresent_pte);
kvm_flush_remote_tlbs(vcpu->kvm);
}
}
static void kvm_mmu_page_unlink_children(struct kvm *kvm,
struct kvm_mmu_page *sp)
{
unsigned i;
u64 *pt;
u64 ent;
pt = sp->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
ent = pt[i];
if (is_shadow_present_pte(ent)) {
if (!is_last_spte(ent, sp->role.level)) {
ent &= PT64_BASE_ADDR_MASK;
mmu_page_remove_parent_pte(page_header(ent),
&pt[i]);
} else {
if (is_large_pte(ent))
--kvm->stat.lpages;
drop_spte(kvm, &pt[i],
shadow_trap_nonpresent_pte);
}
}
pt[i] = shadow_trap_nonpresent_pte;
}
}
static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
{
mmu_page_remove_parent_pte(sp, parent_pte);
}
static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
{
int i;
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm)
vcpu->arch.last_pte_updated = NULL;
}
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
{
u64 *parent_pte;
while (sp->multimapped || sp->parent_pte) {
if (!sp->multimapped)
parent_pte = sp->parent_pte;
else {
struct kvm_pte_chain *chain;
chain = container_of(sp->parent_ptes.first,
struct kvm_pte_chain, link);
parent_pte = chain->parent_ptes[0];
}
BUG_ON(!parent_pte);
kvm_mmu_put_page(sp, parent_pte);
__set_spte(parent_pte, shadow_trap_nonpresent_pte);
}
}
static int mmu_zap_unsync_children(struct kvm *kvm,
struct kvm_mmu_page *parent,
struct list_head *invalid_list)
{
int i, zapped = 0;
struct mmu_page_path parents;
struct kvm_mmu_pages pages;
if (parent->role.level == PT_PAGE_TABLE_LEVEL)
return 0;
kvm_mmu_pages_init(parent, &parents, &pages);
while (mmu_unsync_walk(parent, &pages)) {
struct kvm_mmu_page *sp;
for_each_sp(pages, sp, parents, i) {
kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
mmu_pages_clear_parents(&parents);
zapped++;
}
kvm_mmu_pages_init(parent, &parents, &pages);
}
return zapped;
}
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
struct list_head *invalid_list)
{
int ret;
trace_kvm_mmu_prepare_zap_page(sp);
++kvm->stat.mmu_shadow_zapped;
ret = mmu_zap_unsync_children(kvm, sp, invalid_list);
kvm_mmu_page_unlink_children(kvm, sp);
kvm_mmu_unlink_parents(kvm, sp);
if (!sp->role.invalid && !sp->role.direct)
unaccount_shadowed(kvm, sp->gfn);
if (sp->unsync)
kvm_unlink_unsync_page(kvm, sp);
if (!sp->root_count) {
/* Count self */
ret++;
list_move(&sp->link, invalid_list);
} else {
list_move(&sp->link, &kvm->arch.active_mmu_pages);
kvm_reload_remote_mmus(kvm);
}
sp->role.invalid = 1;
kvm_mmu_reset_last_pte_updated(kvm);
return ret;
}
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
struct list_head *invalid_list)
{
struct kvm_mmu_page *sp;
if (list_empty(invalid_list))
return;
kvm_flush_remote_tlbs(kvm);
do {
sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
WARN_ON(!sp->role.invalid || sp->root_count);
kvm_mmu_free_page(kvm, sp);
} while (!list_empty(invalid_list));
}
/*
* Changing the number of mmu pages allocated to the vm
* Note: if goal_nr_mmu_pages is too small, you will get dead lock
*/
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
{
LIST_HEAD(invalid_list);
/*
* If we set the number of mmu pages to be smaller be than the
* number of actived pages , we must to free some mmu pages before we
* change the value
*/
if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&
!list_empty(&kvm->arch.active_mmu_pages)) {
struct kvm_mmu_page *page;
page = container_of(kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
kvm_mmu_prepare_zap_page(kvm, page, &invalid_list);
kvm_mmu_commit_zap_page(kvm, &invalid_list);
}
goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
}
kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
}
static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
{
struct kvm_mmu_page *sp;
struct hlist_node *node;
LIST_HEAD(invalid_list);
int r;
pgprintk("%s: looking for gfn %llx\n", __func__, gfn);
r = 0;
for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
pgprintk("%s: gfn %llx role %x\n", __func__, gfn,
sp->role.word);
r = 1;
kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
}
kvm_mmu_commit_zap_page(kvm, &invalid_list);
return r;
}
static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
{
struct kvm_mmu_page *sp;
struct hlist_node *node;
LIST_HEAD(invalid_list);
for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
pgprintk("%s: zap %llx %x\n",
__func__, gfn, sp->role.word);
kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
}
kvm_mmu_commit_zap_page(kvm, &invalid_list);
}
static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
{
int slot = memslot_id(kvm, gfn);
struct kvm_mmu_page *sp = page_header(__pa(pte));
__set_bit(slot, sp->slot_bitmap);
}
static void mmu_convert_notrap(struct kvm_mmu_page *sp)
{
int i;
u64 *pt = sp->spt;
if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
return;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
if (pt[i] == shadow_notrap_nonpresent_pte)
__set_spte(&pt[i], shadow_trap_nonpresent_pte);
}
}
/*
* The function is based on mtrr_type_lookup() in
* arch/x86/kernel/cpu/mtrr/generic.c
*/
static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
u64 start, u64 end)
{
int i;
u64 base, mask;
u8 prev_match, curr_match;
int num_var_ranges = KVM_NR_VAR_MTRR;
if (!mtrr_state->enabled)
return 0xFF;
/* Make end inclusive end, instead of exclusive */
end--;
/* Look in fixed ranges. Just return the type as per start */
if (mtrr_state->have_fixed && (start < 0x100000)) {
int idx;
if (start < 0x80000) {
idx = 0;
idx += (start >> 16);
return mtrr_state->fixed_ranges[idx];
} else if (start < 0xC0000) {
idx = 1 * 8;
idx += ((start - 0x80000) >> 14);
return mtrr_state->fixed_ranges[idx];
} else if (start < 0x1000000) {
idx = 3 * 8;
idx += ((start - 0xC0000) >> 12);
return mtrr_state->fixed_ranges[idx];
}
}
/*
* Look in variable ranges
* Look of multiple ranges matching this address and pick type
* as per MTRR precedence
*/
if (!(mtrr_state->enabled & 2))
return mtrr_state->def_type;
prev_match = 0xFF;
for (i = 0; i < num_var_ranges; ++i) {
unsigned short start_state, end_state;
if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
continue;
base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
(mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
(mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
start_state = ((start & mask) == (base & mask));
end_state = ((end & mask) == (base & mask));
if (start_state != end_state)
return 0xFE;
if ((start & mask) != (base & mask))
continue;
curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
if (prev_match == 0xFF) {
prev_match = curr_match;
continue;
}
if (prev_match == MTRR_TYPE_UNCACHABLE ||
curr_match == MTRR_TYPE_UNCACHABLE)
return MTRR_TYPE_UNCACHABLE;
if ((prev_match == MTRR_TYPE_WRBACK &&
curr_match == MTRR_TYPE_WRTHROUGH) ||
(prev_match == MTRR_TYPE_WRTHROUGH &&
curr_match == MTRR_TYPE_WRBACK)) {
prev_match = MTRR_TYPE_WRTHROUGH;
curr_match = MTRR_TYPE_WRTHROUGH;
}
if (prev_match != curr_match)
return MTRR_TYPE_UNCACHABLE;
}
if (prev_match != 0xFF)
return prev_match;
return mtrr_state->def_type;
}
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
{
u8 mtrr;
mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
(gfn << PAGE_SHIFT) + PAGE_SIZE);
if (mtrr == 0xfe || mtrr == 0xff)
mtrr = MTRR_TYPE_WRBACK;
return mtrr;
}
EXPORT_SYMBOL_GPL(kvm_get_guest_memory_type);
static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
trace_kvm_mmu_unsync_page(sp);
++vcpu->kvm->stat.mmu_unsync;
sp->unsync = 1;
kvm_mmu_mark_parents_unsync(sp);
mmu_convert_notrap(sp);
}
static void kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct kvm_mmu_page *s;
struct hlist_node *node;
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
if (s->unsync)
continue;
WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
__kvm_unsync_page(vcpu, s);
}
}
static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
bool can_unsync)
{
struct kvm_mmu_page *s;
struct hlist_node *node;
bool need_unsync = false;
for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
if (!can_unsync)
return 1;
if (s->role.level != PT_PAGE_TABLE_LEVEL)
return 1;
if (!need_unsync && !s->unsync) {
if (!oos_shadow)
return 1;
need_unsync = true;
}
}
if (need_unsync)
kvm_unsync_pages(vcpu, gfn);
return 0;
}
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned pte_access, int user_fault,
int write_fault, int dirty, int level,
gfn_t gfn, pfn_t pfn, bool speculative,
bool can_unsync, bool reset_host_protection)
{
u64 spte;
int ret = 0;
/*
* We don't set the accessed bit, since we sometimes want to see
* whether the guest actually used the pte (in order to detect
* demand paging).
*/
spte = shadow_base_present_pte;
if (!speculative)
spte |= shadow_accessed_mask;
if (!dirty)
pte_access &= ~ACC_WRITE_MASK;
if (pte_access & ACC_EXEC_MASK)
spte |= shadow_x_mask;
else
spte |= shadow_nx_mask;
if (pte_access & ACC_USER_MASK)
spte |= shadow_user_mask;
if (level > PT_PAGE_TABLE_LEVEL)
spte |= PT_PAGE_SIZE_MASK;
if (vcpu->arch.mmu.direct_map)
spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
kvm_is_mmio_pfn(pfn));
if (reset_host_protection)
spte |= SPTE_HOST_WRITEABLE;
spte |= (u64)pfn << PAGE_SHIFT;
if ((pte_access & ACC_WRITE_MASK)
|| (!vcpu->arch.mmu.direct_map && write_fault
&& !is_write_protection(vcpu) && !user_fault)) {
if (level > PT_PAGE_TABLE_LEVEL &&
has_wrprotected_page(vcpu->kvm, gfn, level)) {
ret = 1;
drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
goto done;
}
spte |= PT_WRITABLE_MASK;
if (!vcpu->arch.mmu.direct_map
&& !(pte_access & ACC_WRITE_MASK))
spte &= ~PT_USER_MASK;
/*
* Optimization: for pte sync, if spte was writable the hash
* lookup is unnecessary (and expensive). Write protection
* is responsibility of mmu_get_page / kvm_sync_page.
* Same reasoning can be applied to dirty page accounting.
*/
if (!can_unsync && is_writable_pte(*sptep))
goto set_pte;
if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
pgprintk("%s: found shadow page for %llx, marking ro\n",
__func__, gfn);
ret = 1;
pte_access &= ~ACC_WRITE_MASK;
if (is_writable_pte(spte))
spte &= ~PT_WRITABLE_MASK;
}
}
if (pte_access & ACC_WRITE_MASK)
mark_page_dirty(vcpu->kvm, gfn);
set_pte:
update_spte(sptep, spte);
done:
return ret;
}
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned pt_access, unsigned pte_access,
int user_fault, int write_fault, int dirty,
int *ptwrite, int level, gfn_t gfn,
pfn_t pfn, bool speculative,
bool reset_host_protection)
{
int was_rmapped = 0;
int rmap_count;
pgprintk("%s: spte %llx access %x write_fault %d"
" user_fault %d gfn %llx\n",
__func__, *sptep, pt_access,
write_fault, user_fault, gfn);
if (is_rmap_spte(*sptep)) {
/*
* If we overwrite a PTE page pointer with a 2MB PMD, unlink
* the parent of the now unreachable PTE.
*/
if (level > PT_PAGE_TABLE_LEVEL &&
!is_large_pte(*sptep)) {
struct kvm_mmu_page *child;
u64 pte = *sptep;
child = page_header(pte & PT64_BASE_ADDR_MASK);
mmu_page_remove_parent_pte(child, sptep);
__set_spte(sptep, shadow_trap_nonpresent_pte);
kvm_flush_remote_tlbs(vcpu->kvm);
} else if (pfn != spte_to_pfn(*sptep)) {
pgprintk("hfn old %llx new %llx\n",
spte_to_pfn(*sptep), pfn);
drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
kvm_flush_remote_tlbs(vcpu->kvm);
} else
was_rmapped = 1;
}
if (set_spte(vcpu, sptep, pte_access, user_fault, write_fault,
dirty, level, gfn, pfn, speculative, true,
reset_host_protection)) {
if (write_fault)
*ptwrite = 1;
kvm_mmu_flush_tlb(vcpu);
}
pgprintk("%s: setting spte %llx\n", __func__, *sptep);
pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
is_large_pte(*sptep)? "2MB" : "4kB",
*sptep & PT_PRESENT_MASK ?"RW":"R", gfn,
*sptep, sptep);
if (!was_rmapped && is_large_pte(*sptep))
++vcpu->kvm->stat.lpages;
page_header_update_slot(vcpu->kvm, sptep, gfn);
if (!was_rmapped) {
rmap_count = rmap_add(vcpu, sptep, gfn);
if (rmap_count > RMAP_RECYCLE_THRESHOLD)
rmap_recycle(vcpu, sptep, gfn);
}
kvm_release_pfn_clean(pfn);
if (speculative) {
vcpu->arch.last_pte_updated = sptep;
vcpu->arch.last_pte_gfn = gfn;
}
}
static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
{
}
static struct kvm_memory_slot *
pte_prefetch_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn, bool no_dirty_log)
{
struct kvm_memory_slot *slot;
slot = gfn_to_memslot(vcpu->kvm, gfn);
if (!slot || slot->flags & KVM_MEMSLOT_INVALID ||
(no_dirty_log && slot->dirty_bitmap))
slot = NULL;
return slot;
}
static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
bool no_dirty_log)
{
struct kvm_memory_slot *slot;
unsigned long hva;
slot = pte_prefetch_gfn_to_memslot(vcpu, gfn, no_dirty_log);
if (!slot) {
get_page(bad_page);
return page_to_pfn(bad_page);
}
hva = gfn_to_hva_memslot(slot, gfn);
return hva_to_pfn_atomic(vcpu->kvm, hva);
}
static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp,
u64 *start, u64 *end)
{
struct page *pages[PTE_PREFETCH_NUM];
unsigned access = sp->role.access;
int i, ret;
gfn_t gfn;
gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
if (!pte_prefetch_gfn_to_memslot(vcpu, gfn, access & ACC_WRITE_MASK))
return -1;
ret = gfn_to_page_many_atomic(vcpu->kvm, gfn, pages, end - start);
if (ret <= 0)
return -1;
for (i = 0; i < ret; i++, gfn++, start++)
mmu_set_spte(vcpu, start, ACC_ALL,
access, 0, 0, 1, NULL,
sp->role.level, gfn,
page_to_pfn(pages[i]), true, true);
return 0;
}
static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp, u64 *sptep)
{
u64 *spte, *start = NULL;
int i;
WARN_ON(!sp->role.direct);
i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
spte = sp->spt + i;
for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
if (*spte != shadow_trap_nonpresent_pte || spte == sptep) {
if (!start)
continue;
if (direct_pte_prefetch_many(vcpu, sp, start, spte) < 0)
break;
start = NULL;
} else if (!start)
start = spte;
}
}
static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
{
struct kvm_mmu_page *sp;
/*
* Since it's no accessed bit on EPT, it's no way to
* distinguish between actually accessed translations
* and prefetched, so disable pte prefetch if EPT is
* enabled.
*/
if (!shadow_accessed_mask)
return;
sp = page_header(__pa(sptep));
if (sp->role.level > PT_PAGE_TABLE_LEVEL)
return;
__direct_pte_prefetch(vcpu, sp, sptep);
}
static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
int level, gfn_t gfn, pfn_t pfn)
{
struct kvm_shadow_walk_iterator iterator;
struct kvm_mmu_page *sp;
int pt_write = 0;
gfn_t pseudo_gfn;
for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
if (iterator.level == level) {
mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
0, write, 1, &pt_write,
level, gfn, pfn, false, true);
direct_pte_prefetch(vcpu, iterator.sptep);
++vcpu->stat.pf_fixed;
break;
}
if (*iterator.sptep == shadow_trap_nonpresent_pte) {
u64 base_addr = iterator.addr;
base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
pseudo_gfn = base_addr >> PAGE_SHIFT;
sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
iterator.level - 1,
1, ACC_ALL, iterator.sptep);
if (!sp) {
pgprintk("nonpaging_map: ENOMEM\n");
kvm_release_pfn_clean(pfn);
return -ENOMEM;
}
__set_spte(iterator.sptep,
__pa(sp->spt)
| PT_PRESENT_MASK | PT_WRITABLE_MASK
| shadow_user_mask | shadow_x_mask);
}
}
return pt_write;
}
static void kvm_send_hwpoison_signal(struct kvm *kvm, gfn_t gfn)
{
char buf[1];
void __user *hva;
int r;
/* Touch the page, so send SIGBUS */
hva = (void __user *)gfn_to_hva(kvm, gfn);
r = copy_from_user(buf, hva, 1);
}
static int kvm_handle_bad_page(struct kvm *kvm, gfn_t gfn, pfn_t pfn)
{
kvm_release_pfn_clean(pfn);
if (is_hwpoison_pfn(pfn)) {
kvm_send_hwpoison_signal(kvm, gfn);
return 0;
} else if (is_fault_pfn(pfn))
return -EFAULT;
return 1;
}
static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
{
int r;
int level;
pfn_t pfn;
unsigned long mmu_seq;
level = mapping_level(vcpu, gfn);
/*
* This path builds a PAE pagetable - so we can map 2mb pages at
* maximum. Therefore check if the level is larger than that.
*/
if (level > PT_DIRECTORY_LEVEL)
level = PT_DIRECTORY_LEVEL;
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
/* mmio */
if (is_error_pfn(pfn))
return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, v, write, level, gfn, pfn);
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static void mmu_free_roots(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_mmu_page *sp;
LIST_HEAD(invalid_list);
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
return;
spin_lock(&vcpu->kvm->mmu_lock);
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
sp = page_header(root);
--sp->root_count;
if (!sp->root_count && sp->role.invalid) {
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
}
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
spin_unlock(&vcpu->kvm->mmu_lock);
return;
}
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
if (root) {
root &= PT64_BASE_ADDR_MASK;
sp = page_header(root);
--sp->root_count;
if (!sp->root_count && sp->role.invalid)
kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
&invalid_list);
}
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
}
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
}
static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
{
int ret = 0;
if (!kvm_is_visible_gfn(vcpu->kvm, root_gfn)) {
kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
ret = 1;
}
return ret;
}
static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
{
int i;
gfn_t root_gfn;
struct kvm_mmu_page *sp;
int direct = 0;
u64 pdptr;
root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT;
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
ASSERT(!VALID_PAGE(root));
if (mmu_check_root(vcpu, root_gfn))
return 1;
if (vcpu->arch.mmu.direct_map) {
direct = 1;
root_gfn = 0;
}
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
PT64_ROOT_LEVEL, direct,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = root;
return 0;
}
direct = !is_paging(vcpu);
if (mmu_check_root(vcpu, root_gfn))
return 1;
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
ASSERT(!VALID_PAGE(root));
if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
pdptr = kvm_pdptr_read(vcpu, i);
if (!is_present_gpte(pdptr)) {
vcpu->arch.mmu.pae_root[i] = 0;
continue;
}
root_gfn = pdptr >> PAGE_SHIFT;
if (mmu_check_root(vcpu, root_gfn))
return 1;
} else if (vcpu->arch.mmu.root_level == 0)
root_gfn = 0;
if (vcpu->arch.mmu.direct_map) {
direct = 1;
root_gfn = i << 30;
}
spin_lock(&vcpu->kvm->mmu_lock);
kvm_mmu_free_some_pages(vcpu);
sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
PT32_ROOT_LEVEL, direct,
ACC_ALL, NULL);
root = __pa(sp->spt);
++sp->root_count;
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
}
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
return 0;
}
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
{
int i;
struct kvm_mmu_page *sp;
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
return;
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
sp = page_header(root);
mmu_sync_children(vcpu, sp);
return;
}
for (i = 0; i < 4; ++i) {
hpa_t root = vcpu->arch.mmu.pae_root[i];
if (root && VALID_PAGE(root)) {
root &= PT64_BASE_ADDR_MASK;
sp = page_header(root);
mmu_sync_children(vcpu, sp);
}
}
}
void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
{
spin_lock(&vcpu->kvm->mmu_lock);
mmu_sync_roots(vcpu);
spin_unlock(&vcpu->kvm->mmu_lock);
}
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
u32 access, u32 *error)
{
if (error)
*error = 0;
return vaddr;
}
static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
u32 access, u32 *error)
{
if (error)
*error = 0;
return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access);
}
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
u32 error_code)
{
gfn_t gfn;
int r;
pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
gfn = gva >> PAGE_SHIFT;
return nonpaging_map(vcpu, gva & PAGE_MASK,
error_code & PFERR_WRITE_MASK, gfn);
}
static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
u32 error_code)
{
pfn_t pfn;
int r;
int level;
gfn_t gfn = gpa >> PAGE_SHIFT;
unsigned long mmu_seq;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
level = mapping_level(vcpu, gfn);
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
if (is_error_pfn(pfn))
return kvm_handle_bad_page(vcpu->kvm, gfn, pfn);
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
level, gfn, pfn);
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static void nonpaging_free(struct kvm_vcpu *vcpu)
{
mmu_free_roots(vcpu);
}
static int nonpaging_init_context(struct kvm_vcpu *vcpu,
struct kvm_mmu *context)
{
context->new_cr3 = nonpaging_new_cr3;
context->page_fault = nonpaging_page_fault;
context->gva_to_gpa = nonpaging_gva_to_gpa;
context->free = nonpaging_free;
context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
context->root_level = 0;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
context->direct_map = true;
return 0;
}
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
{
++vcpu->stat.tlb_flush;
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
}
static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
mmu_free_roots(vcpu);
}
static unsigned long get_cr3(struct kvm_vcpu *vcpu)
{
return vcpu->arch.cr3;
}
static void inject_page_fault(struct kvm_vcpu *vcpu)
{
vcpu->arch.mmu.inject_page_fault(vcpu);
}
static void paging_free(struct kvm_vcpu *vcpu)
{
nonpaging_free(vcpu);
}
static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
{
int bit7;
bit7 = (gpte >> 7) & 1;
return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) != 0;
}
#define PTTYPE 64
#include "paging_tmpl.h"
#undef PTTYPE
#define PTTYPE 32
#include "paging_tmpl.h"
#undef PTTYPE
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
struct kvm_mmu *context,
int level)
{
int maxphyaddr = cpuid_maxphyaddr(vcpu);
u64 exb_bit_rsvd = 0;
if (!is_nx(vcpu))
exb_bit_rsvd = rsvd_bits(63, 63);
switch (level) {
case PT32_ROOT_LEVEL:
/* no rsvd bits for 2 level 4K page table entries */
context->rsvd_bits_mask[0][1] = 0;
context->rsvd_bits_mask[0][0] = 0;
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
if (!is_pse(vcpu)) {
context->rsvd_bits_mask[1][1] = 0;
break;
}
if (is_cpuid_PSE36())
/* 36bits PSE 4MB page */
context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
else
/* 32 bits PSE 4MB page */
context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
break;
case PT32E_ROOT_LEVEL:
context->rsvd_bits_mask[0][2] =
rsvd_bits(maxphyaddr, 63) |
rsvd_bits(7, 8) | rsvd_bits(1, 2); /* PDPTE */
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62); /* PDE */
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62); /* PTE */
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62) |
rsvd_bits(13, 20); /* large page */
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
break;
case PT64_ROOT_LEVEL:
context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8);
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 29);
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 20); /* large page */
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
break;
}
}
static int paging64_init_context_common(struct kvm_vcpu *vcpu,
struct kvm_mmu *context,
int level)
{
reset_rsvds_bits_mask(vcpu, context, level);
ASSERT(is_pae(vcpu));
context->new_cr3 = paging_new_cr3;
context->page_fault = paging64_page_fault;
context->gva_to_gpa = paging64_gva_to_gpa;
context->prefetch_page = paging64_prefetch_page;
context->sync_page = paging64_sync_page;
context->invlpg = paging64_invlpg;
context->free = paging_free;
context->root_level = level;
context->shadow_root_level = level;
context->root_hpa = INVALID_PAGE;
context->direct_map = false;
return 0;
}
static int paging64_init_context(struct kvm_vcpu *vcpu,
struct kvm_mmu *context)
{
return paging64_init_context_common(vcpu, context, PT64_ROOT_LEVEL);
}
static int paging32_init_context(struct kvm_vcpu *vcpu,
struct kvm_mmu *context)
{
reset_rsvds_bits_mask(vcpu, context, PT32_ROOT_LEVEL);
context->new_cr3 = paging_new_cr3;
context->page_fault = paging32_page_fault;
context->gva_to_gpa = paging32_gva_to_gpa;
context->free = paging_free;
context->prefetch_page = paging32_prefetch_page;
context->sync_page = paging32_sync_page;
context->invlpg = paging32_invlpg;
context->root_level = PT32_ROOT_LEVEL;
context->shadow_root_level = PT32E_ROOT_LEVEL;
context->root_hpa = INVALID_PAGE;
context->direct_map = false;
return 0;
}
static int paging32E_init_context(struct kvm_vcpu *vcpu,
struct kvm_mmu *context)
{
return paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);
}
static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *context = vcpu->arch.walk_mmu;
context->new_cr3 = nonpaging_new_cr3;
context->page_fault = tdp_page_fault;
context->free = nonpaging_free;
context->prefetch_page = nonpaging_prefetch_page;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
context->shadow_root_level = kvm_x86_ops->get_tdp_level();
context->root_hpa = INVALID_PAGE;
context->direct_map = true;
context->set_cr3 = kvm_x86_ops->set_tdp_cr3;
context->get_cr3 = get_cr3;
context->inject_page_fault = kvm_inject_page_fault;
if (!is_paging(vcpu)) {
context->gva_to_gpa = nonpaging_gva_to_gpa;
context->root_level = 0;
} else if (is_long_mode(vcpu)) {
reset_rsvds_bits_mask(vcpu, context, PT64_ROOT_LEVEL);
context->gva_to_gpa = paging64_gva_to_gpa;
context->root_level = PT64_ROOT_LEVEL;
} else if (is_pae(vcpu)) {
reset_rsvds_bits_mask(vcpu, context, PT32E_ROOT_LEVEL);
context->gva_to_gpa = paging64_gva_to_gpa;
context->root_level = PT32E_ROOT_LEVEL;
} else {
reset_rsvds_bits_mask(vcpu, context, PT32_ROOT_LEVEL);
context->gva_to_gpa = paging32_gva_to_gpa;
context->root_level = PT32_ROOT_LEVEL;
}
return 0;
}
int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
{
int r;
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
if (!is_paging(vcpu))
r = nonpaging_init_context(vcpu, context);
else if (is_long_mode(vcpu))
r = paging64_init_context(vcpu, context);
else if (is_pae(vcpu))
r = paging32E_init_context(vcpu, context);
else
r = paging32_init_context(vcpu, context);
vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
vcpu->arch.mmu.base_role.cr0_wp = is_write_protection(vcpu);
return r;
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
int r = kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
vcpu->arch.walk_mmu->set_cr3 = kvm_x86_ops->set_cr3;
vcpu->arch.walk_mmu->get_cr3 = get_cr3;
vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
return r;
}
static int init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
g_context->get_cr3 = get_cr3;
g_context->inject_page_fault = kvm_inject_page_fault;
/*
* Note that arch.mmu.gva_to_gpa translates l2_gva to l1_gpa. The
* translation of l2_gpa to l1_gpa addresses is done using the
* arch.nested_mmu.gva_to_gpa function. Basically the gva_to_gpa
* functions between mmu and nested_mmu are swapped.
*/
if (!is_paging(vcpu)) {
g_context->root_level = 0;
g_context->gva_to_gpa = nonpaging_gva_to_gpa_nested;
} else if (is_long_mode(vcpu)) {
reset_rsvds_bits_mask(vcpu, g_context, PT64_ROOT_LEVEL);
g_context->root_level = PT64_ROOT_LEVEL;
g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
} else if (is_pae(vcpu)) {
reset_rsvds_bits_mask(vcpu, g_context, PT32E_ROOT_LEVEL);
g_context->root_level = PT32E_ROOT_LEVEL;
g_context->gva_to_gpa = paging64_gva_to_gpa_nested;
} else {
reset_rsvds_bits_mask(vcpu, g_context, PT32_ROOT_LEVEL);
g_context->root_level = PT32_ROOT_LEVEL;
g_context->gva_to_gpa = paging32_gva_to_gpa_nested;
}
return 0;
}
static int init_kvm_mmu(struct kvm_vcpu *vcpu)
{
vcpu->arch.update_pte.pfn = bad_pfn;
if (mmu_is_nested(vcpu))
return init_kvm_nested_mmu(vcpu);
else if (tdp_enabled)
return init_kvm_tdp_mmu(vcpu);
else
return init_kvm_softmmu(vcpu);
}
static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
if (VALID_PAGE(vcpu->arch.mmu.root_hpa))
/* mmu.free() should set root_hpa = INVALID_PAGE */
vcpu->arch.mmu.free(vcpu);
}
int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
{
destroy_kvm_mmu(vcpu);
return init_kvm_mmu(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
int kvm_mmu_load(struct kvm_vcpu *vcpu)
{
int r;
r = mmu_topup_memory_caches(vcpu);
if (r)
goto out;
r = mmu_alloc_roots(vcpu);
spin_lock(&vcpu->kvm->mmu_lock);
mmu_sync_roots(vcpu);
spin_unlock(&vcpu->kvm->mmu_lock);
if (r)
goto out;
/* set_cr3() should ensure TLB has been flushed */
vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
out:
return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_load);
void kvm_mmu_unload(struct kvm_vcpu *vcpu)
{
mmu_free_roots(vcpu);
}
static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp,
u64 *spte)
{
u64 pte;
struct kvm_mmu_page *child;
pte = *spte;
if (is_shadow_present_pte(pte)) {
if (is_last_spte(pte, sp->role.level))
drop_spte(vcpu->kvm, spte, shadow_trap_nonpresent_pte);
else {
child = page_header(pte & PT64_BASE_ADDR_MASK);
mmu_page_remove_parent_pte(child, spte);
}
}
__set_spte(spte, shadow_trap_nonpresent_pte);
if (is_large_pte(pte))
--vcpu->kvm->stat.lpages;
}
static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *sp,
u64 *spte,
const void *new)
{
if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
++vcpu->kvm->stat.mmu_pde_zapped;
return;
}
if (is_rsvd_bits_set(&vcpu->arch.mmu, *(u64 *)new, PT_PAGE_TABLE_LEVEL))
return;
++vcpu->kvm->stat.mmu_pte_updated;
if (!sp->role.cr4_pae)
paging32_update_pte(vcpu, sp, spte, new);
else
paging64_update_pte(vcpu, sp, spte, new);
}
static bool need_remote_flush(u64 old, u64 new)
{
if (!is_shadow_present_pte(old))
return false;
if (!is_shadow_present_pte(new))
return true;
if ((old ^ new) & PT64_BASE_ADDR_MASK)
return true;
old ^= PT64_NX_MASK;
new ^= PT64_NX_MASK;
return (old & ~new & PT64_PERM_MASK) != 0;
}
static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, bool zap_page,
bool remote_flush, bool local_flush)
{
if (zap_page)
return;
if (remote_flush)
kvm_flush_remote_tlbs(vcpu->kvm);
else if (local_flush)
kvm_mmu_flush_tlb(vcpu);
}
static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
{
u64 *spte = vcpu->arch.last_pte_updated;
return !!(spte && (*spte & shadow_accessed_mask));
}
static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
u64 gpte)
{
gfn_t gfn;
pfn_t pfn;
if (!is_present_gpte(gpte))
return;
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
smp_rmb();
pfn = gfn_to_pfn(vcpu->kvm, gfn);
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
return;
}
vcpu->arch.update_pte.gfn = gfn;
vcpu->arch.update_pte.pfn = pfn;
}
static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
{
u64 *spte = vcpu->arch.last_pte_updated;
if (spte
&& vcpu->arch.last_pte_gfn == gfn
&& shadow_accessed_mask
&& !(*spte & shadow_accessed_mask)
&& is_shadow_present_pte(*spte))
set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
}
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes,
bool guest_initiated)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
union kvm_mmu_page_role mask = { .word = 0 };
struct kvm_mmu_page *sp;
struct hlist_node *node;
LIST_HEAD(invalid_list);
u64 entry, gentry;
u64 *spte;
unsigned offset = offset_in_page(gpa);
unsigned pte_size;
unsigned page_offset;
unsigned misaligned;
unsigned quadrant;
int level;
int flooded = 0;
int npte;
int r;
int invlpg_counter;
bool remote_flush, local_flush, zap_page;
zap_page = remote_flush = local_flush = false;
pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
invlpg_counter = atomic_read(&vcpu->kvm->arch.invlpg_counter);
/*
* Assume that the pte write on a page table of the same type
* as the current vcpu paging mode. This is nearly always true
* (might be false while changing modes). Note it is verified later
* by update_pte().
*/
if ((is_pae(vcpu) && bytes == 4) || !new) {
/* Handle a 32-bit guest writing two halves of a 64-bit gpte */
if (is_pae(vcpu)) {
gpa &= ~(gpa_t)7;
bytes = 8;
}
r = kvm_read_guest(vcpu->kvm, gpa, &gentry, min(bytes, 8));
if (r)
gentry = 0;
new = (const u8 *)&gentry;
}
switch (bytes) {
case 4:
gentry = *(const u32 *)new;
break;
case 8:
gentry = *(const u64 *)new;
break;
default:
gentry = 0;
break;
}
mmu_guess_page_from_pte_write(vcpu, gpa, gentry);
spin_lock(&vcpu->kvm->mmu_lock);
if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
gentry = 0;
kvm_mmu_access_page(vcpu, gfn);
kvm_mmu_free_some_pages(vcpu);
++vcpu->kvm->stat.mmu_pte_write;
trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PTE_WRITE);
if (guest_initiated) {
if (gfn == vcpu->arch.last_pt_write_gfn
&& !last_updated_pte_accessed(vcpu)) {
++vcpu->arch.last_pt_write_count;
if (vcpu->arch.last_pt_write_count >= 3)
flooded = 1;
} else {
vcpu->arch.last_pt_write_gfn = gfn;
vcpu->arch.last_pt_write_count = 1;
vcpu->arch.last_pte_updated = NULL;
}
}
mask.cr0_wp = mask.cr4_pae = mask.nxe = 1;
for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node) {
pte_size = sp->role.cr4_pae ? 8 : 4;
misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
misaligned |= bytes < 4;
if (misaligned || flooded) {
/*
* Misaligned accesses are too much trouble to fix
* up; also, they usually indicate a page is not used
* as a page table.
*
* If we're seeing too many writes to a page,
* it may no longer be a page table, or we may be
* forking, in which case it is better to unmap the
* page.
*/
pgprintk("misaligned: gpa %llx bytes %d role %x\n",
gpa, bytes, sp->role.word);
zap_page |= !!kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
&invalid_list);
++vcpu->kvm->stat.mmu_flooded;
continue;
}
page_offset = offset;
level = sp->role.level;
npte = 1;
if (!sp->role.cr4_pae) {
page_offset <<= 1; /* 32->64 */
/*
* A 32-bit pde maps 4MB while the shadow pdes map
* only 2MB. So we need to double the offset again
* and zap two pdes instead of one.
*/
if (level == PT32_ROOT_LEVEL) {
page_offset &= ~7; /* kill rounding error */
page_offset <<= 1;
npte = 2;
}
quadrant = page_offset >> PAGE_SHIFT;
page_offset &= ~PAGE_MASK;
if (quadrant != sp->role.quadrant)
continue;
}
local_flush = true;
spte = &sp->spt[page_offset / sizeof(*spte)];
while (npte--) {
entry = *spte;
mmu_pte_write_zap_pte(vcpu, sp, spte);
if (gentry &&
!((sp->role.word ^ vcpu->arch.mmu.base_role.word)
& mask.word))
mmu_pte_write_new_pte(vcpu, sp, spte, &gentry);
if (!remote_flush && need_remote_flush(entry, *spte))
remote_flush = true;
++spte;
}
}
mmu_pte_write_flush_tlb(vcpu, zap_page, remote_flush, local_flush);
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
trace_kvm_mmu_audit(vcpu, AUDIT_POST_PTE_WRITE);
spin_unlock(&vcpu->kvm->mmu_lock);
if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
vcpu->arch.update_pte.pfn = bad_pfn;
}
}
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
{
gpa_t gpa;
int r;
if (vcpu->arch.mmu.direct_map)
return 0;
gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
spin_lock(&vcpu->kvm->mmu_lock);
r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
{
LIST_HEAD(invalid_list);
while (kvm_mmu_available_pages(vcpu->kvm) < KVM_REFILL_PAGES &&
!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
struct kvm_mmu_page *sp;
sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
++vcpu->kvm->stat.mmu_recycled;
}
}
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
{
int r;
enum emulation_result er;
r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
if (r < 0)
goto out;
if (!r) {
r = 1;
goto out;
}
r = mmu_topup_memory_caches(vcpu);
if (r)
goto out;
er = emulate_instruction(vcpu, cr2, error_code, 0);
switch (er) {
case EMULATE_DONE:
return 1;
case EMULATE_DO_MMIO:
++vcpu->stat.mmio_exits;
/* fall through */
case EMULATE_FAIL:
return 0;
default:
BUG();
}
out:
return r;
}
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
vcpu->arch.mmu.invlpg(vcpu, gva);
kvm_mmu_flush_tlb(vcpu);
++vcpu->stat.invlpg;
}
EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
void kvm_enable_tdp(void)
{
tdp_enabled = true;
}
EXPORT_SYMBOL_GPL(kvm_enable_tdp);
void kvm_disable_tdp(void)
{
tdp_enabled = false;
}
EXPORT_SYMBOL_GPL(kvm_disable_tdp);
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
free_page((unsigned long)vcpu->arch.mmu.pae_root);
}
static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
{
struct page *page;
int i;
ASSERT(vcpu);
/*
* When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
* Therefore we need to allocate shadow page tables in the first
* 4GB of memory, which happens to fit the DMA32 zone.
*/
page = alloc_page(GFP_KERNEL | __GFP_DMA32);
if (!page)
return -ENOMEM;
vcpu->arch.mmu.pae_root = page_address(page);
for (i = 0; i < 4; ++i)
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
return 0;
}
int kvm_mmu_create(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
return alloc_mmu_pages(vcpu);
}
int kvm_mmu_setup(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
return init_kvm_mmu(vcpu);
}
void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
{
ASSERT(vcpu);
destroy_kvm_mmu(vcpu);
free_mmu_pages(vcpu);
mmu_free_memory_caches(vcpu);
}
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
{
struct kvm_mmu_page *sp;
list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
int i;
u64 *pt;
if (!test_bit(slot, sp->slot_bitmap))
continue;
pt = sp->spt;
for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
/* avoid RMW */
if (is_writable_pte(pt[i]))
pt[i] &= ~PT_WRITABLE_MASK;
}
kvm_flush_remote_tlbs(kvm);
}
void kvm_mmu_zap_all(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;
LIST_HEAD(invalid_list);
spin_lock(&kvm->mmu_lock);
restart:
list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
goto restart;
kvm_mmu_commit_zap_page(kvm, &invalid_list);
spin_unlock(&kvm->mmu_lock);
}
static int kvm_mmu_remove_some_alloc_mmu_pages(struct kvm *kvm,
struct list_head *invalid_list)
{
struct kvm_mmu_page *page;
page = container_of(kvm->arch.active_mmu_pages.prev,
struct kvm_mmu_page, link);
return kvm_mmu_prepare_zap_page(kvm, page, invalid_list);
}
static int mmu_shrink(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
{
struct kvm *kvm;
struct kvm *kvm_freed = NULL;
if (nr_to_scan == 0)
goto out;
spin_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
int idx, freed_pages;
LIST_HEAD(invalid_list);
idx = srcu_read_lock(&kvm->srcu);
spin_lock(&kvm->mmu_lock);
if (!kvm_freed && nr_to_scan > 0 &&
kvm->arch.n_used_mmu_pages > 0) {
freed_pages = kvm_mmu_remove_some_alloc_mmu_pages(kvm,
&invalid_list);
kvm_freed = kvm;
}
nr_to_scan--;
kvm_mmu_commit_zap_page(kvm, &invalid_list);
spin_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, idx);
}
if (kvm_freed)
list_move_tail(&kvm_freed->vm_list, &vm_list);
spin_unlock(&kvm_lock);
out:
return percpu_counter_read_positive(&kvm_total_used_mmu_pages);
}
static struct shrinker mmu_shrinker = {
.shrink = mmu_shrink,
.seeks = DEFAULT_SEEKS * 10,
};
static void mmu_destroy_caches(void)
{
if (pte_chain_cache)
kmem_cache_destroy(pte_chain_cache);
if (rmap_desc_cache)
kmem_cache_destroy(rmap_desc_cache);
if (mmu_page_header_cache)
kmem_cache_destroy(mmu_page_header_cache);
}
void kvm_mmu_module_exit(void)
{
mmu_destroy_caches();
percpu_counter_destroy(&kvm_total_used_mmu_pages);
unregister_shrinker(&mmu_shrinker);
}
int kvm_mmu_module_init(void)
{
pte_chain_cache = kmem_cache_create("kvm_pte_chain",
sizeof(struct kvm_pte_chain),
0, 0, NULL);
if (!pte_chain_cache)
goto nomem;
rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
sizeof(struct kvm_rmap_desc),
0, 0, NULL);
if (!rmap_desc_cache)
goto nomem;
mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
sizeof(struct kvm_mmu_page),
0, 0, NULL);
if (!mmu_page_header_cache)
goto nomem;
if (percpu_counter_init(&kvm_total_used_mmu_pages, 0))
goto nomem;
register_shrinker(&mmu_shrinker);
return 0;
nomem:
mmu_destroy_caches();
return -ENOMEM;
}
/*
* Caculate mmu pages needed for kvm.
*/
unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
{
int i;
unsigned int nr_mmu_pages;
unsigned int nr_pages = 0;
struct kvm_memslots *slots;
slots = kvm_memslots(kvm);
for (i = 0; i < slots->nmemslots; i++)
nr_pages += slots->memslots[i].npages;
nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
nr_mmu_pages = max(nr_mmu_pages,
(unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
return nr_mmu_pages;
}
static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
unsigned len)
{
if (len > buffer->len)
return NULL;
return buffer->ptr;
}
static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
unsigned len)
{
void *ret;
ret = pv_mmu_peek_buffer(buffer, len);
if (!ret)
return ret;
buffer->ptr += len;
buffer->len -= len;
buffer->processed += len;
return ret;
}
static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
gpa_t addr, gpa_t value)
{
int bytes = 8;
int r;
if (!is_long_mode(vcpu) && !is_pae(vcpu))
bytes = 4;
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
if (!emulator_write_phys(vcpu, addr, &value, bytes))
return -EFAULT;
return 1;
}
static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
{
(void)kvm_set_cr3(vcpu, vcpu->arch.cr3);
return 1;
}
static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
{
spin_lock(&vcpu->kvm->mmu_lock);
mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
spin_unlock(&vcpu->kvm->mmu_lock);
return 1;
}
static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
struct kvm_pv_mmu_op_buffer *buffer)
{
struct kvm_mmu_op_header *header;
header = pv_mmu_peek_buffer(buffer, sizeof *header);
if (!header)
return 0;
switch (header->op) {
case KVM_MMU_OP_WRITE_PTE: {
struct kvm_mmu_op_write_pte *wpte;
wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
if (!wpte)
return 0;
return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
wpte->pte_val);
}
case KVM_MMU_OP_FLUSH_TLB: {
struct kvm_mmu_op_flush_tlb *ftlb;
ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
if (!ftlb)
return 0;
return kvm_pv_mmu_flush_tlb(vcpu);
}
case KVM_MMU_OP_RELEASE_PT: {
struct kvm_mmu_op_release_pt *rpt;
rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
if (!rpt)
return 0;
return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
}
default: return 0;
}
}
int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
gpa_t addr, unsigned long *ret)
{
int r;
struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
buffer->ptr = buffer->buf;
buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
buffer->processed = 0;
r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
if (r)
goto out;
while (buffer->len) {
r = kvm_pv_mmu_op_one(vcpu, buffer);
if (r < 0)
goto out;
if (r == 0)
break;
}
r = 1;
out:
*ret = buffer->processed;
return r;
}
int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4])
{
struct kvm_shadow_walk_iterator iterator;
int nr_sptes = 0;
spin_lock(&vcpu->kvm->mmu_lock);
for_each_shadow_entry(vcpu, addr, iterator) {
sptes[iterator.level-1] = *iterator.sptep;
nr_sptes++;
if (!is_shadow_present_pte(*iterator.sptep))
break;
}
spin_unlock(&vcpu->kvm->mmu_lock);
return nr_sptes;
}
EXPORT_SYMBOL_GPL(kvm_mmu_get_spte_hierarchy);
#ifdef CONFIG_KVM_MMU_AUDIT
#include "mmu_audit.c"
#endif
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