1 files changed, 15 insertions, 4 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a49df8988cd6..a67e996cbf7f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -724,6 +724,15 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
 	kvm->mn_active_invalidate_count++;
 	spin_unlock(&kvm->mn_invalidate_lock);
 
+	/*
+	 * Invalidate pfn caches _before_ invalidating the secondary MMUs, i.e.
+	 * before acquiring mmu_lock, to avoid holding mmu_lock while acquiring
+	 * each cache's lock.  There are relatively few caches in existence at
+	 * any given time, and the caches themselves can check for hva overlap,
+	 * i.e. don't need to rely on memslot overlap checks for performance.
+	 * Because this runs without holding mmu_lock, the pfn caches must use
+	 * mn_active_invalidate_count (see above) instead of mmu_notifier_count.
+	 */
 	gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end,
 					  hva_range.may_block);
 
@@ -3763,13 +3772,15 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 		return -EINVAL;
 	}
 
+	r = kvm_arch_vcpu_precreate(kvm, id);
+	if (r) {
+		mutex_unlock(&kvm->lock);
+		return r;
+	}
+
 	kvm->created_vcpus++;
 	mutex_unlock(&kvm->lock);
 
-	r = kvm_arch_vcpu_precreate(kvm, id);
-	if (r)
-		goto vcpu_decrement;
-
 	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);
 	if (!vcpu) {
 		r = -ENOMEM;