address_space_dispatch_clear remove subpage with higher priority

Author: PhilippTakacs

qemu/exec.c

@@ -1395,6 +1395,7 @@ static subpage_t *subpage_init(struct uc_struct *uc, FlatView *fv, hwaddr base)
     memory_region_init_io(fv->root->uc, &mmio->iomem, &subpage_ops, mmio,
                           TARGET_PAGE_SIZE);
     mmio->iomem.subpage = true;
+    mmio->iomem.priority = uc->snapshot_level;
 #if defined(DEBUG_SUBPAGE)
     printf("%s: %p base " TARGET_FMT_plx " len %08x\n", __func__,
            mmio, base, TARGET_PAGE_SIZE);
@@ -1457,6 +1458,15 @@ AddressSpaceDispatch *address_space_dispatch_new(struct uc_struct *uc, FlatView
 
 void address_space_dispatch_clear(AddressSpaceDispatch *d)
 {
+    MemoryRegionSection *section;
+    struct uc_struct *uc = d->uc;
+    while (d->map.sections_nb > 0) {
+        d->map.sections_nb--;
+        section = &d->map.sections[d->map.sections_nb];
+        if (section->mr->priority > uc->snapshot_level) {
+            phys_section_destroy(section->mr);
+        }
+    }
     g_free(d->map.sections);
     g_free(d->map.nodes);
     g_free(d);