diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 073617ce83e0..8f58dd20b362 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -95,23 +95,15 @@ EXPORT_SYMBOL_GPL(kvm_free_hpt_cma);
 void __init kvm_cma_reserve(void)
 {
 	unsigned long align_size;
-	struct memblock_region *reg;
-	phys_addr_t selected_size = 0;
+	phys_addr_t selected_size;
 
 	/*
 	 * We need CMA reservation only when we are in HV mode
 	 */
 	if (!cpu_has_feature(CPU_FTR_HVMODE))
 		return;
-	/*
-	 * We cannot use memblock_phys_mem_size() here, because
-	 * memblock_analyze() has not been called yet.
-	 */
-	for_each_memblock(memory, reg)
-		selected_size += memblock_region_memory_end_pfn(reg) -
-				 memblock_region_memory_base_pfn(reg);
 
-	selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
+	selected_size = PAGE_ALIGN(memblock_phys_mem_size() * kvm_cma_resv_ratio / 100);
 	if (selected_size) {
 		pr_info("%s: reserving %ld MiB for global area\n", __func__,
 			 (unsigned long)selected_size / SZ_1M);