KVM: MMU: traverse sp hlish safely

Now, we can safely to traverse sp hlish

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 23 insertions, 28 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 44548e346976..3b75689eda95 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1205,13 +1205,13 @@ static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
 static void kvm_mmu_commit_zap_page(struct kvm *kvm,
                                     struct list_head *invalid_list);
 
-#define for_each_gfn_sp(kvm, sp, gfn, pos, n)                           \
-  hlist_for_each_entry_safe(sp, pos, n,                                 \
+#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, n)            \
-  hlist_for_each_entry_safe(sp, pos, n,                                 \
+#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
@@ -1265,11 +1265,11 @@ static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 static void kvm_sync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
 {
         struct kvm_mmu_page *s;
-        struct hlist_node *node, *n;
+        struct hlist_node *node;
         LIST_HEAD(invalid_list);
         bool flush = false;
 
-        for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node, n) {
+        for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
                 if (!s->unsync)
                         continue;
 
@@ -1387,7 +1387,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
         union kvm_mmu_page_role role;
         unsigned quadrant;
         struct kvm_mmu_page *sp;
-        struct hlist_node *node, *tmp;
+        struct hlist_node *node;
         bool need_sync = false;
 
         role = vcpu->arch.mmu.base_role;
@@ -1401,7 +1401,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
                 role.quadrant = quadrant;
         }
-        for_each_gfn_sp(vcpu->kvm, sp, gfn, node, tmp) {
+        for_each_gfn_sp(vcpu->kvm, sp, gfn, node) {
                 if (!need_sync && sp->unsync)
                         need_sync = true;
 
@@ -1656,19 +1656,18 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_mmu_page *sp;
-        struct hlist_node *node, *n;
+        struct hlist_node *node;
         LIST_HEAD(invalid_list);
         int r;
 
         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
         r = 0;
-restart:
-        for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node, n) {
+
+        for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
                 pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
                          sp->role.word);
                 r = 1;
-                if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
-                        goto restart;
+                kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
         }
         kvm_mmu_commit_zap_page(kvm, &invalid_list);
         return r;
@@ -1677,15 +1676,13 @@ restart:
 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_mmu_page *sp;
-        struct hlist_node *node, *nn;
+        struct hlist_node *node;
         LIST_HEAD(invalid_list);
 
-restart:
-        for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node, nn) {
+        for_each_gfn_indirect_valid_sp(kvm, sp, gfn, node) {
                 pgprintk("%s: zap %lx %x\n",
                          __func__, gfn, sp->role.word);
-                if (kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list))
-                        goto restart;
+                kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
         }
         kvm_mmu_commit_zap_page(kvm, &invalid_list);
 }
@@ -1830,9 +1827,9 @@ static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 static void kvm_unsync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
 {
         struct kvm_mmu_page *s;
-        struct hlist_node *node, *n;
+        struct hlist_node *node;
 
-        for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node, n) {
+        for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
                 if (s->unsync)
                         continue;
                 WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
@@ -1844,10 +1841,10 @@ 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, *n;
+        struct hlist_node *node;
         bool need_unsync = false;
 
-        for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node, n) {
+        for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn, node) {
                 if (s->role.level != PT_PAGE_TABLE_LEVEL)
                         return 1;
 
@@ -2724,7 +2721,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         struct kvm_mmu_page *sp;
-        struct hlist_node *node, *n;
+        struct hlist_node *node;
         LIST_HEAD(invalid_list);
         u64 entry, gentry;
         u64 *spte;
@@ -2794,8 +2791,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                 }
         }
 
-restart:
-        for_each_gfn_indirect_valid_sp(vcpu->kvm, sp, gfn, node, n) {
+        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;
@@ -2812,9 +2808,8 @@ restart:
                          */
                         pgprintk("misaligned: gpa %llx bytes %d role %x\n",
                                  gpa, bytes, sp->role.word);
-                        if (kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
-                                                     &invalid_list))
-                                goto restart;
+                        kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
+                                                     &invalid_list);
                         ++vcpu->kvm->stat.mmu_flooded;
                         continue;
                 }