memory: assert that PhysPageEntry's ptr does not overflow
While sized to 15 bits in PhysPageEntry, the ptr field is ORed into the
iotlb entries together with a page-aligned pointer. The ptr field must
not overflow into this page-aligned value, assert that it is smaller than
the page size.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/exec.c b/exec.c
index 1355661..8562fca 100644
--- a/exec.c
+++ b/exec.c
@@ -713,6 +713,12 @@
static uint16_t phys_section_add(MemoryRegionSection *section)
{
+ /* The physical section number is ORed with a page-aligned
+ * pointer to produce the iotlb entries. Thus it should
+ * never overflow into the page-aligned value.
+ */
+ assert(phys_sections_nb < TARGET_PAGE_SIZE);
+
if (phys_sections_nb == phys_sections_nb_alloc) {
phys_sections_nb_alloc = MAX(phys_sections_nb_alloc * 2, 16);
phys_sections = g_renew(MemoryRegionSection, phys_sections,
