1 files changed, 57 insertions, 22 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7b6084999424..6e8eb15dd30b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -440,6 +440,15 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
 
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
+static void kvm_init_memslots_id(struct kvm *kvm)
+{
+        int i;
+        struct kvm_memslots *slots = kvm->memslots;
+
+        for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+                slots->memslots[i].id = i;
+}
+
 static struct kvm *kvm_create_vm(void)
 {
         int r, i;
@@ -465,6 +474,7 @@ static struct kvm *kvm_create_vm(void)
         kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
         if (!kvm->memslots)
                 goto out_err_nosrcu;
+        kvm_init_memslots_id(kvm);
         if (init_srcu_struct(&kvm->srcu))
                 goto out_err_nosrcu;
         for (i = 0; i < KVM_NR_BUSES; i++) {
@@ -630,15 +640,54 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
 }
 #endif /* !CONFIG_S390 */
 
+static struct kvm_memory_slot *
+search_memslots(struct kvm_memslots *slots, gfn_t gfn)
+{
+        struct kvm_memory_slot *memslot;
+
+        kvm_for_each_memslot(memslot, slots)
+                if (gfn >= memslot->base_gfn &&
+                      gfn < memslot->base_gfn + memslot->npages)
+                        return memslot;
+
+        return NULL;
+}
+
+static int cmp_memslot(const void *slot1, const void *slot2)
+{
+        struct kvm_memory_slot *s1, *s2;
+
+        s1 = (struct kvm_memory_slot *)slot1;
+        s2 = (struct kvm_memory_slot *)slot2;
+
+        if (s1->npages < s2->npages)
+                return 1;
+        if (s1->npages > s2->npages)
+                return -1;
+
+        return 0;
+}
+
+/*
+ * Sort the memslots base on its size, so the larger slots
+ * will get better fit.
+ */
+static void sort_memslots(struct kvm_memslots *slots)
+{
+        sort(slots->memslots, KVM_MEM_SLOTS_NUM,
+              sizeof(struct kvm_memory_slot), cmp_memslot, NULL);
+}
+
 void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
 {
         if (new) {
                 int id = new->id;
                 struct kvm_memory_slot *old = id_to_memslot(slots, id);
+                unsigned long npages = old->npages;
 
                 *old = *new;
-                if (id >= slots->nmemslots)
-                        slots->nmemslots = id + 1;
+                if (new->npages != npages)
+                        sort_memslots(slots);
         }
 
         slots->generation++;
@@ -980,14 +1029,7 @@ EXPORT_SYMBOL_GPL(kvm_is_error_hva);
 static struct kvm_memory_slot *__gfn_to_memslot(struct kvm_memslots *slots,
                                                 gfn_t gfn)
 {
-        struct kvm_memory_slot *memslot;
-
-        kvm_for_each_memslot(memslot, slots)
-                if (gfn >= memslot->base_gfn
-                    && gfn < memslot->base_gfn + memslot->npages)
-                        return memslot;
-
-        return NULL;
+        return search_memslots(slots, gfn);
 }
 
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
@@ -998,20 +1040,13 @@ EXPORT_SYMBOL_GPL(gfn_to_memslot);
 
 int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
 {
-        int i;
-        struct kvm_memslots *slots = kvm_memslots(kvm);
-
-        for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
-                struct kvm_memory_slot *memslot = &slots->memslots[i];
+        struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
 
-                if (memslot->flags & KVM_MEMSLOT_INVALID)
-                        continue;
+        if (!memslot || memslot->id >= KVM_MEMORY_SLOTS ||
+              memslot->flags & KVM_MEMSLOT_INVALID)
+                return 0;
 
-                if (gfn >= memslot->base_gfn
-                    && gfn < memslot->base_gfn + memslot->npages)
-                        return 1;
-        }
-        return 0;
+        return 1;
 }
 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);