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Commit cea0f0e7 authored by Avi Kivity's avatar Avi Kivity Committed by Linus Torvalds
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[PATCH] KVM: MMU: Shadow page table caching 



Define a hashtable for caching shadow page tables. Look up the cache on
context switch (cr3 change) or during page faults.

The key to the cache is a combination of
- the guest page table frame number
- the number of paging levels in the guest
   * we can cache real mode, 32-bit mode, pae, and long mode page
     tables simultaneously.  this is useful for smp bootup.
- the guest page table table
   * some kernels use a page as both a page table and a page directory.  this
     allows multiple shadow pages to exist for that page, one per level
- the "quadrant"
   * 32-bit mode page tables span 4MB, whereas a shadow page table spans
     2MB.  similarly, a 32-bit page directory spans 4GB, while a shadow
     page directory spans 1GB.  the quadrant allows caching up to 4 shadow page
     tables for one guest page in one level.
- a "metaphysical" bit
   * for real mode, and for pse pages, there is no guest page table, so set
     the bit to avoid write protecting the page.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 25c0de2c

drivers/kvm/kvm.h

+44 −1
Original line number Diff line number Diff line
@@ -89,14 +89,53 @@ typedef unsigned long hva_t; 
typedef u64            hpa_t;

typedef unsigned long  hfn_t;



#define NR_PTE_CHAIN_ENTRIES 5



struct kvm_pte_chain {

	u64 *parent_ptes[NR_PTE_CHAIN_ENTRIES];

	struct hlist_node link;

};



/*

 * kvm_mmu_page_role, below, is defined as:

 *

 *   bits 0:3 - total guest paging levels (2-4, or zero for real mode)

 *   bits 4:7 - page table level for this shadow (1-4)

 *   bits 8:9 - page table quadrant for 2-level guests

 *   bit   16 - "metaphysical" - gfn is not a real page (huge page/real mode)

 */

union kvm_mmu_page_role {

	unsigned word;

	struct {

		unsigned glevels : 4;

		unsigned level : 4;

		unsigned quadrant : 2;

		unsigned pad_for_nice_hex_output : 6;

		unsigned metaphysical : 1;

	};

};



struct kvm_mmu_page {

	struct list_head link;

	struct hlist_node hash_link;



	/*

	 * The following two entries are used to key the shadow page in the

	 * hash table.

	 */

	gfn_t gfn;

	union kvm_mmu_page_role role;



	hpa_t page_hpa;

	unsigned long slot_bitmap; /* One bit set per slot which has memory

				    * in this shadow page.

				    */

	int global;              /* Set if all ptes in this page are global */

	u64 *parent_pte;

	int multimapped;         /* More than one parent_pte? */

	union {

		u64 *parent_pte;               /* !multimapped */

		struct hlist_head parent_ptes; /* multimapped, kvm_pte_chain */

	};

};



struct vmcs {
@@ -235,7 +274,11 @@ struct kvm { 
	spinlock_t lock; /* protects everything except vcpus */

	int nmemslots;

	struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS];

	/*

	 * Hash table of struct kvm_mmu_page.

	 */

	struct list_head active_mmu_pages;

	struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];

	struct kvm_vcpu vcpus[KVM_MAX_VCPUS];

	int memory_config_version;

	int busy;

drivers/kvm/mmu.c

+183 −24
Original line number Diff line number Diff line
@@ -26,8 +26,8 @@ 
#include "vmx.h"

#include "kvm.h"



#define pgprintk(x...) do { } while (0)

#define rmap_printk(x...) do { } while (0)

#define pgprintk(x...) do { printk(x); } while (0)

#define rmap_printk(x...) do { printk(x); } while (0)



#define ASSERT(x)							\

	if (!(x)) {							\
@@ -35,8 +35,10 @@ 
		       __FILE__, __LINE__, #x);				\

	}



#define PT64_ENT_PER_PAGE 512

#define PT32_ENT_PER_PAGE 1024

#define PT64_PT_BITS 9

#define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)

#define PT32_PT_BITS 10

#define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)



#define PT_WRITABLE_SHIFT 1
@@ -292,6 +294,11 @@ static int is_empty_shadow_page(hpa_t page_hpa) 
	return 1;

}



static unsigned kvm_page_table_hashfn(gfn_t gfn)

{

	return gfn;

}



static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,

					       u64 *parent_pte)

{
@@ -306,10 +313,147 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, 
	ASSERT(is_empty_shadow_page(page->page_hpa));

	page->slot_bitmap = 0;

	page->global = 1;

	page->multimapped = 0;

	page->parent_pte = parent_pte;

	return page;

}



static void mmu_page_add_parent_pte(struct kvm_mmu_page *page, u64 *parent_pte)

{

	struct kvm_pte_chain *pte_chain;

	struct hlist_node *node;

	int i;



	if (!parent_pte)

		return;

	if (!page->multimapped) {

		u64 *old = page->parent_pte;



		if (!old) {

			page->parent_pte = parent_pte;

			return;

		}

		page->multimapped = 1;

		pte_chain = kzalloc(sizeof(struct kvm_pte_chain), GFP_NOWAIT);

		BUG_ON(!pte_chain);

		INIT_HLIST_HEAD(&page->parent_ptes);

		hlist_add_head(&pte_chain->link, &page->parent_ptes);

		pte_chain->parent_ptes[0] = old;

	}

	hlist_for_each_entry(pte_chain, node, &page->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 = kzalloc(sizeof(struct kvm_pte_chain), GFP_NOWAIT);

	BUG_ON(!pte_chain);

	hlist_add_head(&pte_chain->link, &page->parent_ptes);

	pte_chain->parent_ptes[0] = parent_pte;

}



static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page,

				       u64 *parent_pte)

{

	struct kvm_pte_chain *pte_chain;

	struct hlist_node *node;

	int i;



	if (!page->multimapped) {

		BUG_ON(page->parent_pte != parent_pte);

		page->parent_pte = NULL;

		return;

	}

	hlist_for_each_entry(pte_chain, node, &page->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]

					= pte_chain->parent_ptes[i + 1];

				++i;

			}

			pte_chain->parent_ptes[i] = NULL;

			return;

		}

	BUG();

}



static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm_vcpu *vcpu,

						gfn_t gfn)

{

	unsigned index;

	struct hlist_head *bucket;

	struct kvm_mmu_page *page;

	struct hlist_node *node;



	pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);

	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;

	bucket = &vcpu->kvm->mmu_page_hash[index];

	hlist_for_each_entry(page, node, bucket, hash_link)

		if (page->gfn == gfn && !page->role.metaphysical) {

			pgprintk("%s: found role %x\n",

				 __FUNCTION__, page->role.word);

			return page;

		}

	return NULL;

}



static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,

					     gfn_t gfn,

					     gva_t gaddr,

					     unsigned level,

					     int metaphysical,

					     u64 *parent_pte)

{

	union kvm_mmu_page_role role;

	unsigned index;

	unsigned quadrant;

	struct hlist_head *bucket;

	struct kvm_mmu_page *page;

	struct hlist_node *node;



	role.word = 0;

	role.glevels = vcpu->mmu.root_level;

	role.level = level;

	role.metaphysical = metaphysical;

	if (vcpu->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;

	}

	pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,

		 gfn, role.word);

	index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;

	bucket = &vcpu->kvm->mmu_page_hash[index];

	hlist_for_each_entry(page, node, bucket, hash_link)

		if (page->gfn == gfn && page->role.word == role.word) {

			mmu_page_add_parent_pte(page, parent_pte);

			pgprintk("%s: found\n", __FUNCTION__);

			return page;

		}

	page = kvm_mmu_alloc_page(vcpu, parent_pte);

	if (!page)

		return page;

	pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word);

	page->gfn = gfn;

	page->role = role;

	hlist_add_head(&page->hash_link, bucket);

	return page;

}



static void kvm_mmu_put_page(struct kvm_vcpu *vcpu,

			     struct kvm_mmu_page *page,

			     u64 *parent_pte)

{

	mmu_page_remove_parent_pte(page, parent_pte);

}



static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa)

{

	int slot = memslot_id(kvm, gfn_to_memslot(kvm, gpa >> PAGE_SHIFT));
@@ -389,11 +533,15 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p) 
	for (; ; level--) {

		u32 index = PT64_INDEX(v, level);

		u64 *table;

		u64 pte;



		ASSERT(VALID_PAGE(table_addr));

		table = __va(table_addr);



		if (level == 1) {

			pte = table[index];

			if (is_present_pte(pte) && is_writeble_pte(pte))

				return 0;

			mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);

			page_header_update_slot(vcpu->kvm, table, v);

			table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK |
@@ -404,8 +552,13 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p) 


		if (table[index] == 0) {

			struct kvm_mmu_page *new_table;

			gfn_t pseudo_gfn;



			new_table = kvm_mmu_alloc_page(vcpu, &table[index]);

			pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)

				>> PAGE_SHIFT;

			new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,

						     v, level - 1,

						     1, &table[index]);

			if (!new_table) {

				pgprintk("nonpaging_map: ENOMEM\n");

				return -ENOMEM;
@@ -427,7 +580,6 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu) 
		hpa_t root = vcpu->mmu.root_hpa;



		ASSERT(VALID_PAGE(root));

		release_pt_page_64(vcpu, root, PT64_ROOT_LEVEL);

		vcpu->mmu.root_hpa = INVALID_PAGE;

		return;

	}
@@ -437,7 +589,6 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu) 


		ASSERT(VALID_PAGE(root));

		root &= PT64_BASE_ADDR_MASK;

		release_pt_page_64(vcpu, root, PT32E_ROOT_LEVEL - 1);

		vcpu->mmu.pae_root[i] = INVALID_PAGE;

	}

	vcpu->mmu.root_hpa = INVALID_PAGE;
@@ -446,13 +597,16 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu) 
static void mmu_alloc_roots(struct kvm_vcpu *vcpu)

{

	int i;

	gfn_t root_gfn;

	root_gfn = vcpu->cr3 >> PAGE_SHIFT;



#ifdef CONFIG_X86_64

	if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {

		hpa_t root = vcpu->mmu.root_hpa;



		ASSERT(!VALID_PAGE(root));

		root = kvm_mmu_alloc_page(vcpu, NULL)->page_hpa;

		root = kvm_mmu_get_page(vcpu, root_gfn, 0,

					PT64_ROOT_LEVEL, 0, NULL)->page_hpa;

		vcpu->mmu.root_hpa = root;

		return;

	}
@@ -461,7 +615,13 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu) 
		hpa_t root = vcpu->mmu.pae_root[i];



		ASSERT(!VALID_PAGE(root));

		root = kvm_mmu_alloc_page(vcpu, NULL)->page_hpa;

		if (vcpu->mmu.root_level == PT32E_ROOT_LEVEL)

			root_gfn = vcpu->pdptrs[i] >> PAGE_SHIFT;

		else if (vcpu->mmu.root_level == 0)

			root_gfn = 0;

		root = kvm_mmu_get_page(vcpu, root_gfn, i << 30,

					PT32_ROOT_LEVEL, !is_paging(vcpu),

					NULL)->page_hpa;

		vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK;

	}

	vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root);
@@ -529,7 +689,7 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu) 
	context->inval_page = nonpaging_inval_page;

	context->gva_to_gpa = nonpaging_gva_to_gpa;

	context->free = nonpaging_free;

	context->root_level = PT32E_ROOT_LEVEL;

	context->root_level = 0;

	context->shadow_root_level = PT32E_ROOT_LEVEL;

	mmu_alloc_roots(vcpu);

	ASSERT(VALID_PAGE(context->root_hpa));
@@ -537,29 +697,18 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu) 
	return 0;

}





static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)

{

	struct kvm_mmu_page *page, *npage;



	list_for_each_entry_safe(page, npage, &vcpu->kvm->active_mmu_pages,

				 link) {

		if (page->global)

			continue;



		if (!page->parent_pte)

			continue;



		*page->parent_pte = 0;

		release_pt_page_64(vcpu, page->page_hpa, 1);

	}

	++kvm_stat.tlb_flush;

	kvm_arch_ops->tlb_flush(vcpu);

}



static void paging_new_cr3(struct kvm_vcpu *vcpu)

{

	mmu_free_roots(vcpu);

	mmu_alloc_roots(vcpu);

	kvm_mmu_flush_tlb(vcpu);

	kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);

}



static void mark_pagetable_nonglobal(void *shadow_pte)
@@ -578,6 +727,16 @@ static inline void set_pte_common(struct kvm_vcpu *vcpu, 
	*shadow_pte |= access_bits << PT_SHADOW_BITS_OFFSET;

	if (!dirty)

		access_bits &= ~PT_WRITABLE_MASK;

	if (access_bits & PT_WRITABLE_MASK) {

		struct kvm_mmu_page *shadow;



		shadow = kvm_mmu_lookup_page(vcpu, gaddr >> PAGE_SHIFT);

		if (shadow)

			pgprintk("%s: found shadow page for %lx, marking ro\n",

				 __FUNCTION__, (gfn_t)(gaddr >> PAGE_SHIFT));

		if (shadow)

			access_bits &= ~PT_WRITABLE_MASK;

	}



	if (access_bits & PT_WRITABLE_MASK)

		mark_page_dirty(vcpu->kvm, gaddr >> PAGE_SHIFT);

drivers/kvm/paging_tmpl.h

+53 −9
Original line number Diff line number Diff line
@@ -32,6 +32,11 @@ 
	#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)

	#define PT_LEVEL_MASK(level) PT64_LEVEL_MASK(level)

	#define PT_PTE_COPY_MASK PT64_PTE_COPY_MASK

	#ifdef CONFIG_X86_64

	#define PT_MAX_FULL_LEVELS 4

	#else

	#define PT_MAX_FULL_LEVELS 2

	#endif

#elif PTTYPE == 32

	#define pt_element_t u32

	#define guest_walker guest_walker32
@@ -42,6 +47,7 @@ 
	#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)

	#define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)

	#define PT_PTE_COPY_MASK PT32_PTE_COPY_MASK

	#define PT_MAX_FULL_LEVELS 2

#else

	#error Invalid PTTYPE value

#endif
@@ -52,7 +58,7 @@ 
 */

struct guest_walker {

	int level;

	gfn_t table_gfn;

	gfn_t table_gfn[PT_MAX_FULL_LEVELS];

	pt_element_t *table;

	pt_element_t *ptep;

	pt_element_t inherited_ar;
@@ -68,7 +74,9 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 
	struct kvm_memory_slot *slot;

	pt_element_t *ptep;

	pt_element_t root;

	gfn_t table_gfn;



	pgprintk("%s: addr %lx\n", __FUNCTION__, addr);

	walker->level = vcpu->mmu.root_level;

	walker->table = NULL;

	root = vcpu->cr3;
@@ -81,8 +89,11 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 
		--walker->level;

	}

#endif

	walker->table_gfn = (root & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

	slot = gfn_to_memslot(vcpu->kvm, walker->table_gfn);

	table_gfn = (root & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

	walker->table_gfn[walker->level - 1] = table_gfn;

	pgprintk("%s: table_gfn[%d] %lx\n", __FUNCTION__,

		 walker->level - 1, table_gfn);

	slot = gfn_to_memslot(vcpu->kvm, table_gfn);

	hpa = safe_gpa_to_hpa(vcpu, root & PT64_BASE_ADDR_MASK);

	walker->table = kmap_atomic(pfn_to_page(hpa >> PAGE_SHIFT), KM_USER0);
@@ -111,12 +122,15 @@ static void FNAME(walk_addr)(struct guest_walker *walker, 


		if (walker->level != 3 || is_long_mode(vcpu))

			walker->inherited_ar &= walker->table[index];

		walker->table_gfn = (*ptep & PT_BASE_ADDR_MASK) >> PAGE_SHIFT;

		table_gfn = (*ptep & PT_BASE_ADDR_MASK) >> PAGE_SHIFT;

		paddr = safe_gpa_to_hpa(vcpu, *ptep & PT_BASE_ADDR_MASK);

		kunmap_atomic(walker->table, KM_USER0);

		walker->table = kmap_atomic(pfn_to_page(paddr >> PAGE_SHIFT),

					    KM_USER0);

		--walker->level;

		walker->table_gfn[walker->level - 1 ] = table_gfn;

		pgprintk("%s: table_gfn[%d] %lx\n", __FUNCTION__,

			 walker->level - 1, table_gfn);

	}

	walker->ptep = ptep;

}
@@ -181,6 +195,8 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, 
		u64 *shadow_ent = ((u64 *)__va(shadow_addr)) + index;

		struct kvm_mmu_page *shadow_page;

		u64 shadow_pte;

		int metaphysical;

		gfn_t table_gfn;



		if (is_present_pte(*shadow_ent) || is_io_pte(*shadow_ent)) {

			if (level == PT_PAGE_TABLE_LEVEL)
@@ -205,7 +221,17 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, 
			return shadow_ent;

		}



		shadow_page = kvm_mmu_alloc_page(vcpu, shadow_ent);

		if (level - 1 == PT_PAGE_TABLE_LEVEL

		    && walker->level == PT_DIRECTORY_LEVEL) {

			metaphysical = 1;

			table_gfn = (*guest_ent & PT_BASE_ADDR_MASK)

				>> PAGE_SHIFT;

		} else {

			metaphysical = 0;

			table_gfn = walker->table_gfn[level - 2];

		}

		shadow_page = kvm_mmu_get_page(vcpu, table_gfn, addr, level-1,

					       metaphysical, shadow_ent);

		if (!shadow_page)

			return ERR_PTR(-ENOMEM);

		shadow_addr = shadow_page->page_hpa;
@@ -227,7 +253,8 @@ static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu, 
			       u64 *shadow_ent,

			       struct guest_walker *walker,

			       gva_t addr,

			       int user)

			       int user,

			       int *write_pt)

{

	pt_element_t *guest_ent;

	int writable_shadow;
@@ -264,6 +291,12 @@ static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu, 
	}



	gfn = (*guest_ent & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

	if (kvm_mmu_lookup_page(vcpu, gfn)) {

		pgprintk("%s: found shadow page for %lx, marking ro\n",

			 __FUNCTION__, gfn);

		*write_pt = 1;

		return 0;

	}

	mark_page_dirty(vcpu->kvm, gfn);

	*shadow_ent |= PT_WRITABLE_MASK;

	*guest_ent |= PT_DIRTY_MASK;
@@ -294,7 +327,9 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, 
	struct guest_walker walker;

	u64 *shadow_pte;

	int fixed;

	int write_pt = 0;



	pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code);

	/*

	 * Look up the shadow pte for the faulting address.

	 */
@@ -302,6 +337,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, 
		FNAME(walk_addr)(&walker, vcpu, addr);

		shadow_pte = FNAME(fetch)(vcpu, addr, &walker);

		if (IS_ERR(shadow_pte)) {  /* must be -ENOMEM */

			printk("%s: oom\n", __FUNCTION__);

			nonpaging_flush(vcpu);

			FNAME(release_walker)(&walker);

			continue;
@@ -313,20 +349,27 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, 
	 * The page is not mapped by the guest.  Let the guest handle it.

	 */

	if (!shadow_pte) {

		pgprintk("%s: not mapped\n", __FUNCTION__);

		inject_page_fault(vcpu, addr, error_code);

		FNAME(release_walker)(&walker);

		return 0;

	}



	pgprintk("%s: shadow pte %p %llx\n", __FUNCTION__,

		 shadow_pte, *shadow_pte);



	/*

	 * Update the shadow pte.

	 */

	if (write_fault)

		fixed = FNAME(fix_write_pf)(vcpu, shadow_pte, &walker, addr,

					    user_fault);

					    user_fault, &write_pt);

	else

		fixed = fix_read_pf(shadow_pte);



	pgprintk("%s: updated shadow pte %p %llx\n", __FUNCTION__,

		 shadow_pte, *shadow_pte);



	FNAME(release_walker)(&walker);



	/*
@@ -344,14 +387,14 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, 
	/*

	 * pte not present, guest page fault.

	 */

	if (pte_present && !fixed) {

	if (pte_present && !fixed && !write_pt) {

		inject_page_fault(vcpu, addr, error_code);

		return 0;

	}



	++kvm_stat.pf_fixed;



	return 0;

	return write_pt;

}



static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)
@@ -395,3 +438,4 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr) 
#undef PT_PTE_COPY_MASK

#undef PT_NON_PTE_COPY_MASK

#undef PT_DIR_BASE_ADDR_MASK

#undef PT_MAX_FULL_LEVELS