1 files changed, 5 insertions, 6 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 605697e9c4dd..1ecbe2391c8b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -920,6 +920,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
         int r;
         gfn_t base_gfn;
         unsigned long npages;
+        int largepages;
         unsigned long i;
         struct kvm_memory_slot *memslot;
         struct kvm_memory_slot old, new;
@@ -960,7 +961,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
         for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
                 struct kvm_memory_slot *s = &kvm->memslots[i];
 
-                if (s == memslot)
+                if (s == memslot || !s->npages)
                         continue;
                 if (!((base_gfn + npages <= s->base_gfn) ||
                       (base_gfn >= s->base_gfn + s->npages)))
@@ -995,11 +996,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
                         new.userspace_addr = 0;
         }
         if (npages && !new.lpage_info) {
-                int largepages = npages / KVM_PAGES_PER_HPAGE;
-                if (npages % KVM_PAGES_PER_HPAGE)
-                        largepages++;
-                if (base_gfn % KVM_PAGES_PER_HPAGE)
-                        largepages++;
+                largepages = 1 + (base_gfn + npages - 1) / KVM_PAGES_PER_HPAGE;
+                largepages -= base_gfn / KVM_PAGES_PER_HPAGE;
 
                 new.lpage_info = vmalloc(largepages * sizeof(*new.lpage_info));
 
@@ -1985,6 +1983,7 @@ static long kvm_dev_ioctl_check_extension_generic(long arg)
         switch (arg) {
         case KVM_CAP_USER_MEMORY:
         case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
+        case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
                 return 1;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
         case KVM_CAP_IRQ_ROUTING: