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>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 048849d..eda82cd 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -499,6 +499,10 @@
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,
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
index a3da98b..b24bc7c 100644
--- a/drivers/kvm/paging_tmpl.h
+++ b/drivers/kvm/paging_tmpl.h
@@ -110,7 +110,7 @@
index = PT_INDEX(addr, walker->level);
table_gfn = gpte_to_gfn(pte);
- pte_gpa = table_gfn << PAGE_SHIFT;
+ pte_gpa = gfn_to_gpa(table_gfn);
pte_gpa += index * sizeof(pt_element_t);
walker->table_gfn[walker->level - 1] = table_gfn;
pgprintk("%s: table_gfn[%d] %lx\n", __FUNCTION__,
@@ -442,7 +442,7 @@
r = FNAME(walk_addr)(&walker, vcpu, vaddr, 0, 0, 0);
if (r) {
- gpa = (gpa_t)walker.gfn << PAGE_SHIFT;
+ gpa = gfn_to_gpa(walker.gfn);
gpa |= vaddr & ~PAGE_MASK;
}
