KVM: MMU: Introduce gfn_to_gpa()

Converting a frame number to an address is tricky since the data type changes
size.  Introduce a function to do it.  This fixes an actual bug when
accessing guest ptes.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 048849d97b3..eda82cded88 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -499,6 +499,10 @@ static inline int memslot_id(struct kvm *kvm, struct kvm_memory_slot *slot)
         return slot - kvm->memslots;
 }
 
+static inline gpa_t gfn_to_gpa(gfn_t gfn)
+{
+        return (gpa_t)gfn << PAGE_SHIFT;
+}
 
 enum kvm_stat_kind {
         KVM_STAT_VM,