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>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 44548e346976013c26508f747e8aba06d536135c..3b75689eda95f9bb4fc583580b01f5b2b68e0bc7 100644 (file)
--- 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;
                }