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Subject[PATCH v3 3/5] KVM: MMU: unify the code of walking pte list
Current code has two ways to walk pte_list, the one is pte_list_walk and
the another way is rmap_get_first and rmap_get_next, they have the same logic.

This patch introduces for_each_spte_in_pte_list to integrate their code

[ Impact: no logic changed, most of the change is function/struct rename ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
---
arch/x86/kvm/mmu.c | 178 ++++++++++++++++++++++------------------------
arch/x86/kvm/mmu_audit.c | 5 +-
2 files changed, 86 insertions(+), 97 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a0dc0d7..2291ea3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -945,26 +945,75 @@ 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 pte_list_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 pte_list link because in such cases the
+ * information in the itererator may not be valid.
+ *
+ * Returns sptep if found, NULL otherwise.
+ */
+static u64 *pte_list_get_first(unsigned long pte_list,
+ struct pte_list_iterator *iter)
{
- struct pte_list_desc *desc;
- int i;
+ if (!pte_list)
+ return NULL;

- if (!*pte_list)
- return;
+ if (!(pte_list & 1)) {
+ iter->desc = NULL;
+ return (u64 *)pte_list;
+ }
+
+ iter->desc = (struct pte_list_desc *)(pte_list & ~1ul);
+ iter->pos = 0;
+ return iter->desc->sptes[iter->pos];
+}
+
+/*
+ * Must be used with a valid iterator: e.g. after pte_list_get_next().
+ *
+ * Returns sptep if found, NULL otherwise.
+ */
+static u64 *pte_list_get_next(struct pte_list_iterator *iter)
+{
+ if (iter->desc) {
+ if (iter->pos < PTE_LIST_EXT - 1) {
+ u64 *sptep;
+
+ ++iter->pos;
+ sptep = iter->desc->sptes[iter->pos];
+ if (sptep)
+ return sptep;
+ }

- if (!(*pte_list & 1))
- return fn((u64 *)*pte_list);
+ iter->desc = iter->desc->more;

- 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->desc) {
+ iter->pos = 0;
+ /* desc->sptes[0] cannot be NULL */
+ return iter->desc->sptes[iter->pos];
+ }
}
+
+ return NULL;
}

+#define for_each_spte_in_pte_list(pte_list, iter, spte) \
+ for (spte = pte_list_get_first(pte_list, &(iter)); \
+ spte != NULL; spte = pte_list_get_next(&(iter)))
+
+#define for_each_spte_in_rmap(rmap, iter, spte) \
+ for_each_spte_in_pte_list(rmap, iter, spte)
+
static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
struct kvm_memory_slot *slot)
{
@@ -1016,67 +1065,6 @@ 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)
-{
- if (!rmap)
- return NULL;
-
- if (!(rmap & 1)) {
- iter->desc = NULL;
- return (u64 *)rmap;
- }
-
- iter->desc = (struct pte_list_desc *)(rmap & ~1ul);
- iter->pos = 0;
- return iter->desc->sptes[iter->pos];
-}
-
-/*
- * 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)
-{
- if (iter->desc) {
- if (iter->pos < PTE_LIST_EXT - 1) {
- u64 *sptep;
-
- ++iter->pos;
- sptep = iter->desc->sptes[iter->pos];
- if (sptep)
- return sptep;
- }
-
- iter->desc = iter->desc->more;
-
- if (iter->desc) {
- iter->pos = 0;
- /* desc->sptes[0] cannot be NULL */
- return iter->desc->sptes[iter->pos];
- }
- }
-
- return NULL;
-}
-
static void drop_spte(struct kvm *kvm, u64 *sptep)
{
if (mmu_spte_clear_track_bits(sptep))
@@ -1137,14 +1125,13 @@ static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
bool pt_protect)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct pte_list_iterator iter;
bool flush = false;

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
+ for_each_spte_in_rmap(*rmapp, iter, sptep) {
BUG_ON(!(*sptep & PT_PRESENT_MASK));

flush |= spte_write_protect(kvm, sptep, pt_protect);
- sptep = rmap_get_next(&iter);
}

return flush;
@@ -1198,15 +1185,14 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
struct kvm_memory_slot *slot, unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct pte_list_iterator iter;
int need_tlb_flush = 0;

- while ((sptep = rmap_get_first(*rmapp, &iter))) {
- BUG_ON(!(*sptep & PT_PRESENT_MASK));
- rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep);
-
+restart:
+ for_each_spte_in_rmap(*rmapp, iter, sptep) {
drop_spte(kvm, sptep);
need_tlb_flush = 1;
+ goto restart;
}

return need_tlb_flush;
@@ -1216,7 +1202,7 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
struct kvm_memory_slot *slot, unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct pte_list_iterator iter;
int need_flush = 0;
u64 new_spte;
pte_t *ptep = (pte_t *)data;
@@ -1228,7 +1214,7 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
if (pte_write(*ptep))
need_flush = kvm_unmap_rmapp(kvm, rmapp, slot, data);
else
- for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
+ for_each_spte_in_rmap(*rmapp, iter, sptep) {
BUG_ON(!is_shadow_present_pte(*sptep));
rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n",
sptep, *sptep);
@@ -1244,7 +1230,6 @@ 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);
}

if (need_flush)
@@ -1335,7 +1320,7 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
struct kvm_memory_slot *slot, unsigned long data)
{
u64 *sptep;
- struct rmap_iterator uninitialized_var(iter);
+ struct pte_list_iterator uninitialized_var(iter);
int young = 0;

/*
@@ -1351,8 +1336,7 @@ static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
goto out;
}

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter)) {
+ for_each_spte_in_rmap(*rmapp, iter, sptep) {
BUG_ON(!is_shadow_present_pte(*sptep));

if (*sptep & shadow_accessed_mask) {
@@ -1371,7 +1355,7 @@ static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
struct kvm_memory_slot *slot, unsigned long data)
{
u64 *sptep;
- struct rmap_iterator iter;
+ struct pte_list_iterator iter;
int young = 0;

/*
@@ -1382,8 +1366,7 @@ 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_spte_in_rmap(*rmapp, iter, sptep) {
BUG_ON(!is_shadow_present_pte(*sptep));

if (*sptep & shadow_accessed_mask) {
@@ -1515,7 +1498,11 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
static void mark_unsync(u64 *spte);
static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
{
- pte_list_walk(&sp->parent_ptes, mark_unsync);
+ struct pte_list_iterator iter;
+ u64 *spte;
+
+ for_each_spte_in_pte_list(sp->parent_ptes, iter, spte)
+ mark_unsync(spte);
}

static void mark_unsync(u64 *spte)
@@ -2035,10 +2022,13 @@ 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 pte_list_iterator iter;

- while ((sptep = rmap_get_first(sp->parent_ptes, &iter)))
+restart:
+ for_each_spte_in_pte_list(sp->parent_ptes, iter, sptep) {
drop_parent_pte(sp, sptep);
+ goto restart;
+ }
}

static int mmu_zap_unsync_children(struct kvm *kvm,
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index daff69e..a08d384 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -190,15 +190,14 @@ static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
{
unsigned long *rmapp;
u64 *sptep;
- struct rmap_iterator iter;
+ struct pte_list_iterator iter;

if (sp->role.direct || sp->unsync || sp->role.invalid)
return;

rmapp = gfn_to_rmap(kvm, sp->gfn, PT_PAGE_TABLE_LEVEL);

- for (sptep = rmap_get_first(*rmapp, &iter); sptep;
- sptep = rmap_get_next(&iter)) {
+ for_each_spte_in_rmap(*rmapp, iter, sptep) {
if (is_writable_pte(*sptep))
audit_printk(kvm, "shadow page has writable "
"mappings: gfn %llx role %x\n",
--
1.7.7.6


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