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Subject[PATCH v2 4/7] KVM: MMU: abstract the operation of rmap
Abstract the operation of rmap to spte_list, then we can use it for the
reverse mapping of parent pte in the later patch

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/mmu.c | 260 +++++++++++++++++++++------------------
2 files changed, 140 insertions(+), 122 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 152601a..0d824e4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -347,7 +347,7 @@ struct kvm_vcpu_arch {
struct kvm_pv_mmu_op_buffer mmu_op_buffer;

struct kvm_mmu_memory_cache mmu_pte_chain_cache;
- struct kvm_mmu_memory_cache mmu_rmap_desc_cache;
+ struct kvm_mmu_memory_cache mmu_pte_list_desc_cache;
struct kvm_mmu_memory_cache mmu_page_cache;
struct kvm_mmu_memory_cache mmu_page_header_cache;

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ad520d4..5ba347b 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -148,7 +148,7 @@ module_param(oos_shadow, bool, 0644);
#define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
| PT64_NX_MASK)

-#define RMAP_EXT 4
+#define PTE_LIST_EXT 4

#define ACC_EXEC_MASK 1
#define ACC_WRITE_MASK PT_WRITABLE_MASK
@@ -164,9 +164,9 @@ module_param(oos_shadow, bool, 0644);

#define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)

-struct kvm_rmap_desc {
- u64 *sptes[RMAP_EXT];
- struct kvm_rmap_desc *more;
+struct pte_list_desc {
+ u64 *sptes[PTE_LIST_EXT];
+ struct pte_list_desc *more;
};

struct kvm_shadow_walk_iterator {
@@ -185,7 +185,7 @@ struct kvm_shadow_walk_iterator {
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 *pte_list_desc_cache;
static struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;

@@ -401,8 +401,8 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
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);
+ r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
+ pte_list_desc_cache, 4 + PTE_PREFETCH_NUM);
if (r)
goto out;
r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
@@ -416,8 +416,10 @@ out:

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(&vcpu->arch.mmu_pte_chain_cache,
+ pte_chain_cache);
+ mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
+ pte_list_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);
@@ -444,15 +446,15 @@ 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)
+static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
{
- return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
- sizeof(struct kvm_rmap_desc));
+ return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache,
+ sizeof(struct pte_list_desc));
}

-static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
+static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
{
- kmem_cache_free(rmap_desc_cache, rd);
+ kmem_cache_free(pte_list_desc_cache, pte_list_desc);
}

static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
@@ -590,67 +592,42 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
}

/*
- * 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;
- struct kvm_lpage_info *linfo;
-
- slot = gfn_to_memslot(kvm, gfn);
- if (likely(level == PT_PAGE_TABLE_LEVEL))
- return &slot->rmap[gfn - slot->base_gfn];
-
- linfo = lpage_info_slot(gfn, slot, level);
-
- return &linfo->rmap_pde;
-}
-
-/*
- * Reverse mapping data structures:
+ * Pte mapping structures:
*
- * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
- * that points to page_address(page).
+ * If pte_list bit zero is zero, then pte_list point to the spte.
*
- * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
- * containing more mappings.
+ * If pte_list bit zero is one, (then pte_list & ~1) points to a struct
+ * pte_list_desc containing more mappings.
*
- * Returns the number of rmap entries before the spte was added or zero if
+ * Returns the number of pte 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)
+static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte,
+ unsigned long *pte_list)
{
- struct kvm_mmu_page *sp;
- struct kvm_rmap_desc *desc;
- unsigned long *rmapp;
+ struct pte_list_desc *desc;
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;
+ if (!*pte_list) {
+ rmap_printk("pte_list_add: %p %llx 0->1\n", spte, *spte);
+ *pte_list = (unsigned long)spte;
+ } else if (!(*pte_list & 1)) {
+ rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte);
+ desc = mmu_alloc_pte_list_desc(vcpu);
+ desc->sptes[0] = (u64 *)*pte_list;
desc->sptes[1] = spte;
- *rmapp = (unsigned long)desc | 1;
+ *pte_list = (unsigned long)desc | 1;
++count;
} 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) {
+ rmap_printk("pte_list_add: %p %llx many->many\n", spte, *spte);
+ desc = (struct pte_list_desc *)(*pte_list & ~1ul);
+ while (desc->sptes[PTE_LIST_EXT-1] && desc->more) {
desc = desc->more;
- count += RMAP_EXT;
+ count += PTE_LIST_EXT;
}
- if (desc->sptes[RMAP_EXT-1]) {
- desc->more = mmu_alloc_rmap_desc(vcpu);
+ if (desc->sptes[PTE_LIST_EXT-1]) {
+ desc->more = mmu_alloc_pte_list_desc(vcpu);
desc = desc->more;
}
for (i = 0; desc->sptes[i]; ++i)
@@ -660,59 +637,78 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
return count;
}

-static void rmap_desc_remove_entry(unsigned long *rmapp,
- struct kvm_rmap_desc *desc,
- int i,
- struct kvm_rmap_desc *prev_desc)
+static u64 *pte_list_next(unsigned long *pte_list, u64 *spte)
+{
+ struct pte_list_desc *desc;
+ u64 *prev_spte;
+ int i;
+
+ if (!*pte_list)
+ return NULL;
+ else if (!(*pte_list & 1)) {
+ if (!spte)
+ return (u64 *)*pte_list;
+ return NULL;
+ }
+ desc = (struct pte_list_desc *)(*pte_list & ~1ul);
+ prev_spte = NULL;
+ while (desc) {
+ for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) {
+ if (prev_spte == spte)
+ return desc->sptes[i];
+ prev_spte = desc->sptes[i];
+ }
+ desc = desc->more;
+ }
+ return NULL;
+}
+
+static void
+pte_list_desc_remove_entry(unsigned long *pte_list, struct pte_list_desc *desc,
+ int i, struct pte_list_desc *prev_desc)
{
int j;

- for (j = RMAP_EXT - 1; !desc->sptes[j] && j > i; --j)
+ for (j = PTE_LIST_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];
+ *pte_list = (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);
+ *pte_list = (unsigned long)desc->more | 1;
+ mmu_free_pte_list_desc(desc);
}

-static void rmap_remove(struct kvm *kvm, u64 *spte)
+static void pte_list_remove(u64 *spte, unsigned long *pte_list)
{
- struct kvm_rmap_desc *desc;
- struct kvm_rmap_desc *prev_desc;
- struct kvm_mmu_page *sp;
- gfn_t gfn;
- unsigned long *rmapp;
+ struct pte_list_desc *desc;
+ struct pte_list_desc *prev_desc;
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);
+ if (!*pte_list) {
+ printk(KERN_ERR "pte_list_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);
+ } else if (!(*pte_list & 1)) {
+ rmap_printk("pte_list_remove: %p 1->0\n", spte);
+ if ((u64 *)*pte_list != spte) {
+ printk(KERN_ERR "pte_list_remove: %p 1->BUG\n", spte);
BUG();
}
- *rmapp = 0;
+ *pte_list = 0;
} else {
- rmap_printk("rmap_remove: %p many->many\n", spte);
- desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
+ rmap_printk("pte_list_remove: %p many->many\n", spte);
+ desc = (struct pte_list_desc *)(*pte_list & ~1ul);
prev_desc = NULL;
while (desc) {
- for (i = 0; i < RMAP_EXT && desc->sptes[i]; ++i)
+ for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
if (desc->sptes[i] == spte) {
- rmap_desc_remove_entry(rmapp,
+ pte_list_desc_remove_entry(pte_list,
desc, i,
prev_desc);
return;
@@ -720,11 +716,59 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
prev_desc = desc;
desc = desc->more;
}
- pr_err("rmap_remove: %p many->many\n", spte);
+ pr_err("pte_list_remove: %p many->many\n", spte);
BUG();
}
}

+/*
+ * 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;
+ struct kvm_lpage_info *linfo;
+
+ slot = gfn_to_memslot(kvm, gfn);
+ if (likely(level == PT_PAGE_TABLE_LEVEL))
+ return &slot->rmap[gfn - slot->base_gfn];
+
+ linfo = lpage_info_slot(gfn, slot, level);
+
+ return &linfo->rmap_pde;
+}
+
+static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
+{
+ struct kvm_mmu_page *sp;
+ unsigned long *rmapp;
+
+ if (!is_rmap_spte(*spte))
+ return 0;
+
+ 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);
+ return pte_list_add(vcpu, spte, rmapp);
+}
+
+static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
+{
+ return pte_list_next(rmapp, spte);
+}
+
+static void rmap_remove(struct kvm *kvm, u64 *spte)
+{
+ struct kvm_mmu_page *sp;
+ gfn_t gfn;
+ unsigned long *rmapp;
+
+ sp = page_header(__pa(spte));
+ gfn = kvm_mmu_page_get_gfn(sp, spte - sp->spt);
+ rmapp = gfn_to_rmap(kvm, gfn, sp->role.level);
+ pte_list_remove(spte, rmapp);
+}
+
static int set_spte_track_bits(u64 *sptep, u64 new_spte)
{
pfn_t pfn;
@@ -752,32 +796,6 @@ static void drop_spte(struct kvm *kvm, u64 *sptep, u64 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;
@@ -3600,8 +3618,8 @@ 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 (pte_list_desc_cache)
+ kmem_cache_destroy(pte_list_desc_cache);
if (mmu_page_header_cache)
kmem_cache_destroy(mmu_page_header_cache);
}
@@ -3613,10 +3631,10 @@ int kvm_mmu_module_init(void)
0, 0, NULL);
if (!pte_chain_cache)
goto nomem;
- rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
- sizeof(struct kvm_rmap_desc),
+ pte_list_desc_cache = kmem_cache_create("pte_list_desc",
+ sizeof(struct pte_list_desc),
0, 0, NULL);
- if (!rmap_desc_cache)
+ if (!pte_list_desc_cache)
goto nomem;

mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
--
1.7.4.4


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