diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -2308,11 +2308,11 @@
 	int domain, i, j, pages;
 
 	/*
-	 * We strongly depend on the size being a power of two, so the assert
-	 * is overzealous. However, should the struct be resized to a
-	 * different power of two, the code below needs to be revisited.
+	 * We depend on the size being evenly divisible into a page so
+	 * that the pv_table array can be indexed directly while
+	 * safely spanning multiple pages from different domains.
 	 */
-	CTASSERT((sizeof(*pvd) == 64));
+	CTASSERT(PAGE_SIZE % sizeof(*pvd) == 0);
 
 	/*
 	 * Calculate the size of the array.
diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -1351,11 +1351,11 @@
 	int domain, i, j, pages;
 
 	/*
-	 * We strongly depend on the size being a power of two, so the assert
-	 * is overzealous. However, should the struct be resized to a
-	 * different power of two, the code below needs to be revisited.
+	 * We depend on the size being evenly divisible into a page so
+	 * that the pv_table array can be indexed directly while
+	 * safely spanning multiple pages from different domains.
 	 */
-	CTASSERT((sizeof(*pvd) == 64));
+	CTASSERT(PAGE_SIZE % sizeof(*pvd) == 0);
 
 	/*
 	 * Calculate the size of the array.