diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
index 9866dfda5f..570b0977c3 100644
--- a/hw/display/xenfb.c
+++ b/hw/display/xenfb.c
@@ -472,9 +472,9 @@ static int xenfb_map_fb(struct XenFB *xenfb)
         xenfb->pixels = NULL;
     }
 
-    xenfb->fbpages = (xenfb->fb_len + (XC_PAGE_SIZE - 1)) / XC_PAGE_SIZE;
+    xenfb->fbpages = DIV_ROUND_UP(xenfb->fb_len, XC_PAGE_SIZE);
     n_fbdirs = xenfb->fbpages * mode / 8;
-    n_fbdirs = (n_fbdirs + (XC_PAGE_SIZE - 1)) / XC_PAGE_SIZE;
+    n_fbdirs = DIV_ROUND_UP(n_fbdirs, XC_PAGE_SIZE);
 
     pgmfns = g_malloc0(sizeof(xen_pfn_t) * n_fbdirs);
     fbmfns = g_malloc0(sizeof(xen_pfn_t) * xenfb->fbpages);
diff --git a/xen-hvm.c b/xen-hvm.c
index 01ee25de21..a0da8d7d91 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -567,7 +567,7 @@ static void xen_sync_dirty_bitmap(XenIOState *state,
 {
     hwaddr npages = size >> TARGET_PAGE_BITS;
     const int width = sizeof(unsigned long) * 8;
-    unsigned long bitmap[(npages + width - 1) / width];
+    unsigned long bitmap[DIV_ROUND_UP(npages, width)];
     int rc, i, j;
     const XenPhysmap *physmap = NULL;