KVM: introduce a table to map slot id to index in memslots array

[platform/adaptation/renesas_rcar/renesas_kernel.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4c2900c..e289486 100644 (file)
--- 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->id_to_index[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++) {
@@ -630,14 +640,59 @@ 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)
+{
+       int i;
+
+       sort(slots->memslots, KVM_MEM_SLOTS_NUM,
+             sizeof(struct kvm_memory_slot), cmp_memslot, NULL);
+
+       for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+               slots->id_to_index[slots->memslots[i].id] = i;
+}
+
 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;
 
-               slots->memslots[id] = *new;
-               if (id >= slots->nmemslots)
-                       slots->nmemslots = id + 1;
+               *old = *new;
+               if (new->npages != npages)
+                       sort_memslots(slots);
        }
 
        slots->generation++;
@@ -681,7 +736,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
        if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
                goto out;
 
-       memslot = &kvm->memslots->memslots[mem->slot];
+       memslot = id_to_memslot(kvm->memslots, mem->slot);
        base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
        npages = mem->memory_size >> PAGE_SHIFT;
 
@@ -788,12 +843,16 @@ skip_lpage:
 #endif /* not defined CONFIG_S390 */
 
        if (!npages) {
+               struct kvm_memory_slot *slot;
+
                r = -ENOMEM;
                slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
                                GFP_KERNEL);
                if (!slots)
                        goto out_free;
-               slots->memslots[mem->slot].flags |= KVM_MEMSLOT_INVALID;
+               slot = id_to_memslot(slots, mem->slot);
+               slot->flags |= KVM_MEMSLOT_INVALID;
+
                update_memslots(slots, NULL);
 
                old_memslots = kvm->memslots;
@@ -897,7 +956,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
        if (log->slot >= KVM_MEMORY_SLOTS)
                goto out;
 
-       memslot = &kvm->memslots->memslots[log->slot];
+       memslot = id_to_memslot(kvm->memslots, log->slot);
        r = -ENOENT;
        if (!memslot->dirty_bitmap)
                goto out;
@@ -975,14 +1034,7 @@ 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)
@@ -993,20 +1045,13 @@ 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);
+       struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
 
-       for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
-               struct kvm_memory_slot *memslot = &slots->memslots[i];
-
-               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);