KVM: Cache the last used slot index per vCPU

[linux-2.6-microblaze.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1984c73..30d3225 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -415,6 +415,7 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
        vcpu->preempted = false;
        vcpu->ready = false;
        preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
+       vcpu->last_used_slot = 0;
 }
 
 void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
@@ -2025,7 +2026,26 @@ EXPORT_SYMBOL_GPL(gfn_to_memslot);
 
 struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
-       return __gfn_to_memslot(kvm_vcpu_memslots(vcpu), gfn);
+       struct kvm_memslots *slots = kvm_vcpu_memslots(vcpu);
+       struct kvm_memory_slot *slot;
+       int slot_index;
+
+       slot = try_get_memslot(slots, vcpu->last_used_slot, gfn);
+       if (slot)
+               return slot;
+
+       /*
+        * Fall back to searching all memslots. We purposely use
+        * search_memslots() instead of __gfn_to_memslot() to avoid
+        * thrashing the VM-wide last_used_index in kvm_memslots.
+        */
+       slot = search_memslots(slots, gfn, &slot_index);
+       if (slot) {
+               vcpu->last_used_slot = slot_index;
+               return slot;
+       }
+
+       return NULL;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot);