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Message-ID: <4F87FC19.8080404@linux.vnet.ibm.com>
Date: Fri, 13 Apr 2012 18:12:41 +0800
From: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
To: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
CC: Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>,
LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH v2 07/16] KVM: MMU: introduce for_each_pte_list_spte
It is used to walk all the sptes of the specified pte_list, after
this, the code of pte_list_walk can be removed
And it can restart the walking automatically if the spte is zapped
Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
---
arch/x86/kvm/mmu.c | 233 +++++++++++++++++++++++-----------------------
arch/x86/kvm/mmu_audit.c | 6 +-
2 files changed, 118 insertions(+), 121 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a1c3628..4e91e94 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -900,26 +900,110 @@ static void pte_list_remove(u64 *spte, unsigned long *pte_list)
}
}
-typedef void (*pte_list_walk_fn) (u64 *spte);
-static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn)
-{
+/*
+ * Used by the following functions to iterate through the sptes linked by a
+ * pte_list. All fields are private and not assumed to be used outside.
+ */
+struct spte_iterator {
+ /* private fields */
+ unsigned long *pte_list;
+ /* holds the sptep if not NULL */
struct pte_list_desc *desc;
- int i;
+ /* index of the sptep, -1 means the walking does not start. */
+ int pos;
+};
- if (!*pte_list)
- return;
+static void pte_list_walk_init(struct spte_iterator *iter,
+ unsigned long *pte_list)
+{
+ iter->pte_list = pte_list;
+ iter->pos = -1;
+}
+
+static void pte_list_walk_check_restart(struct spte_iterator *iter, u64 *spte)
+{
+ /*
+ * If the spte is zapped, we should set 'iter->pos = -1' to restart
+ * the walk.
+ */
+ if (!is_shadow_present_pte(*spte))
+ iter->pos = -1;
+}
+
+static u64 *pte_list_first(struct spte_iterator *iter)
+{
+ unsigned long pte_list = *iter->pte_list;
+ u64 *sptep;
+
+ if (!pte_list)
+ return NULL;
+
+ if (!(pte_list & 1)) {
+ iter->desc = NULL;
+ iter->pos = 0;
+ sptep = (u64 *)pte_list;
+
+ goto exit;
+ }
+
+ iter->desc = (struct pte_list_desc *)(pte_list & ~1ul);
+ iter->pos = 0;
+ sptep = iter->desc->sptes[iter->pos];
+
+exit:
+ WARN_ON(sptep && !is_shadow_present_pte(*sptep));
+ return sptep;
+}
- if (!(*pte_list & 1))
- return fn((u64 *)*pte_list);
+static u64 *pte_list_next(struct spte_iterator *iter)
+{
+ u64 *sptep = NULL;
- desc = (struct pte_list_desc *)(*pte_list & ~1ul);
- while (desc) {
- for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
- fn(desc->sptes[i]);
- desc = desc->more;
+ if (iter->pos < 0)
+ return pte_list_first(iter);
+
+ if (iter->desc) {
+ if (iter->pos < PTE_LIST_EXT - 1) {
+ ++iter->pos;
+ sptep = iter->desc->sptes[iter->pos];
+ if (sptep)
+ goto exit;
+ }
+
+ iter->desc = iter->desc->more;
+
+ if (iter->desc) {
+ iter->pos = 0;
+ /* desc->sptes[0] cannot be NULL */
+ sptep = iter->desc->sptes[iter->pos];
+ goto exit;
+ }
}
+
+exit:
+ WARN_ON(sptep && !is_shadow_present_pte(*sptep));
+ return sptep;
}
+
+#define for_each_pte_list_spte(pte_list, iter, spte) \
+ for (pte_list_walk_init(iter, pte_list); \
+ (spte = pte_list_next(iter)) != NULL; \
+ pte_list_walk_check_restart(iter, spte))
+
+typedef void (*pte_list_walk_fn) (u64 *spte);
+static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn)
+{
+ struct spte_iterator iter;
+ u64 *spte;
+
+ for_each_pte_list_spte(pte_list, &iter, spte)
+ fn(spte);
+}
+
+#define for_each_rmap_spte(rmap, iter, spte) \
+ for_each_pte_list_spte(rmap, iter, spte)
+
static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
struct kvm_memory_slot *slot)
{
@@ -974,92 +1058,19 @@ static void rmap_remove(struct kvm *kvm, u64 *spte)
pte_list_remove(spte, rmapp);
}
-/*
- * Used by the following functions to iterate through the sptes linked by a
- * rmap. All fields are private and not assumed to be used outside.
- */
-struct rmap_iterator {
- /* private fields */
- struct pte_list_desc *desc; /* holds the sptep if not NULL */
- int pos; /* index of the sptep */
-};
-
-/*
- * Iteration must be started by this function. This should also be used after
- * removing/dropping sptes from the rmap link because in such cases the
- * information in the itererator may not be valid.
- *
- * Returns sptep if found, NULL otherwise.
- */
-static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter)
-{
- u64 *sptep;
-
- if (!rmap)
- return NULL;
-
- if (!(rmap & 1)) {
- iter->desc = NULL;
- sptep = (u64 *)rmap;
-
- goto exit;
- }
-
- iter->desc = (struct pte_list_desc *)(rmap & ~1ul);
- iter->pos = 0;
- sptep = iter->desc->sptes[iter->pos];
-
-exit:
- WARN_ON(sptep && !is_shadow_present_pte(*sptep));
- return sptep;
-}
-
-/*
- * Must be used with a valid iterator: e.g. after rmap_get_first().
- *
- * Returns sptep if found, NULL otherwise.
- */
-static u64 *rmap_get_next(struct rmap_iterator *iter)
-{
- u64 *sptep = NULL;
-
- if (iter->desc) {
- if (iter->pos < PTE_LIST_EXT - 1) {
- ++iter->pos;
- sptep = iter->desc->sptes[iter->pos];
- if (sptep)
- goto exit;
- }
-
- iter->desc = iter->desc->more;
-
- if (iter->desc) {
- iter->pos = 0;
- /* desc->sptes[0] cannot be NULL */
- sptep = iter->desc->sptes[iter->pos];
- goto exit;
- }
- }
-
-exit:
- WARN_ON(sptep && !is_shadow_present_pte(*sptep));
- return sptep;
-}
-
static void drop_spte(struct kvm *kvm, u64 *sptep)
{
if (mmu_spte_clear_track_bits(sptep))
rmap_remove(kvm, sptep);
}
-/* Return true if the spte is dropped. */
-static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool large,
+static void spte_write_protect(struct kvm *kvm, u64 *sptep, bool large,
bool *flush)
{
u64 spte = *sptep;
if (!is_writable_pte(spte))
- return false;
+ return;
*flush |= true;
@@ -1070,32 +1081,24 @@ static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool large,
drop_spte(kvm, sptep);
--kvm->stat.lpages;
- return true;
+ return;
}
rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
spte = spte & ~PT_WRITABLE_MASK;
mmu_spte_update(sptep, spte);
-
- return false;
}
static bool
__rmap_write_protect(struct kvm *kvm, unsigned long *rmapp, int level)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
bool write_protected = false;
- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
- if (spte_write_protect(kvm, sptep, level > PT_PAGE_TABLE_LEVEL,
- &write_protected)) {
- sptep = rmap_get_first(*rmapp, &iter);
- continue;
- }
-
- sptep = rmap_get_next(&iter);
- }
+ for_each_rmap_spte(rmapp, &iter, sptep)
+ spte_write_protect(kvm, sptep, level > PT_PAGE_TABLE_LEVEL,
+ &write_protected);
return write_protected;
}
@@ -1147,10 +1150,10 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
int need_tlb_flush = 0;
- while ((sptep = rmap_get_first(*rmapp, &iter))) {
+ for_each_rmap_spte(rmapp, &iter, sptep) {
rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep);
drop_spte(kvm, sptep);
@@ -1164,7 +1167,7 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
int need_flush = 0;
u64 new_spte;
pte_t *ptep = (pte_t *)data;
@@ -1173,15 +1176,14 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
WARN_ON(pte_huge(*ptep));
new_pfn = pte_pfn(*ptep);
- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
+ for_each_rmap_spte(rmapp, &iter, sptep) {
rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", sptep, *sptep);
need_flush = 1;
- if (pte_write(*ptep)) {
+ if (pte_write(*ptep))
drop_spte(kvm, sptep);
- sptep = rmap_get_first(*rmapp, &iter);
- } else {
+ else {
new_spte = *sptep & ~PT64_BASE_ADDR_MASK;
new_spte |= (u64)new_pfn << PAGE_SHIFT;
@@ -1191,7 +1193,6 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
mmu_spte_clear_track_bits(sptep);
mmu_spte_set(sptep, new_spte);
- sptep = rmap_get_next(&iter);
}
}
@@ -1254,7 +1255,7 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
int young = 0;
/*
@@ -1267,8 +1268,7 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
if (!shadow_accessed_mask)
return kvm_unmap_rmapp(kvm, rmapp, data);
- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter))
+ for_each_rmap_spte(rmapp, &iter, sptep)
if (*sptep & PT_ACCESSED_MASK) {
young = 1;
clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)sptep);
@@ -1281,7 +1281,7 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
int young = 0;
/*
@@ -1292,8 +1292,7 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
if (!shadow_accessed_mask)
goto out;
- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter))
+ for_each_rmap_spte(rmapp, &iter, sptep)
if (*sptep & PT_ACCESSED_MASK) {
young = 1;
break;
@@ -1955,9 +1954,9 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
- while ((sptep = rmap_get_first(sp->parent_ptes, &iter)))
+ for_each_pte_list_spte(&sp->parent_ptes, &iter, sptep)
drop_parent_pte(sp, sptep);
}
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index 7d7d0b9..a42bd85 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -193,7 +193,7 @@ static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
struct kvm_memory_slot *slot;
unsigned long *rmapp;
u64 *sptep;
- struct rmap_iterator iter;
+ struct spte_iterator iter;
if (sp->role.direct || sp->unsync || sp->role.invalid)
return;
@@ -201,13 +201,11 @@ static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
slot = gfn_to_memslot(kvm, sp->gfn);
rmapp = &slot->rmap[sp->gfn - slot->base_gfn];
- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter)) {
+ for_each_rmap_spte(rmapp, &iter, sptep)
if (is_writable_pte(*sptep))
audit_printk(kvm, "shadow page has writable "
"mappings: gfn %llx role %x\n",
sp->gfn, sp->role.word);
- }
}
static void audit_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
--
1.7.7.6
--
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