KVM: Prevent overflow in largepages calculation

If userspace specifies a memory slot that is larger than 8 petabytes, it
could overflow the largepages variable.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5f865ed..e211945 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1087,8 +1087,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
        int r;
        gfn_t base_gfn;
        unsigned long npages, ugfn;
-       int largepages;
-       unsigned long i;
+       unsigned long largepages, i;
        struct kvm_memory_slot *memslot;
        struct kvm_memory_slot old, new;