diff --git a/exec.c b/exec.c
index 35ce8329e1..bea2cffd94 100644
--- a/exec.c
+++ b/exec.c
@@ -717,14 +717,14 @@ static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
                              uint16_t section);
 static subpage_t *subpage_init(AddressSpace *as, hwaddr base);
 
-static void *(*phys_mem_alloc)(ram_addr_t size) = qemu_anon_ram_alloc;
+static void *(*phys_mem_alloc)(size_t size) = qemu_anon_ram_alloc;
 
 /*
  * Set a custom physical guest memory alloator.
  * Accelerators with unusual needs may need this.  Hopefully, we can
  * get rid of it eventually.
  */
-void phys_mem_set_alloc(void *(*alloc)(ram_addr_t))
+void phys_mem_set_alloc(void *(*alloc)(size_t))
 {
     phys_mem_alloc = alloc;
 }
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 6ad05cacf5..ea90b649d4 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -322,7 +322,7 @@ extern uintptr_t tci_tb_ptr;
 
 #if !defined(CONFIG_USER_ONLY)
 
-void phys_mem_set_alloc(void *(*alloc)(ram_addr_t));
+void phys_mem_set_alloc(void *(*alloc)(size_t));
 
 struct MemoryRegion *iotlb_to_region(hwaddr index);
 bool io_mem_read(struct MemoryRegion *mr, hwaddr addr,
diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index a444f6999b..02ac4ba995 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -93,7 +93,7 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
 
 static int cap_sync_regs;
 
-static void *legacy_s390_alloc(ram_addr_t size);
+static void *legacy_s390_alloc(size_t size);
 
 int kvm_arch_init(KVMState *s)
 {
@@ -325,7 +325,7 @@ int kvm_s390_get_registers_partial(CPUState *cs)
  * to grow. We also have to use MAP parameters that avoid
  * read-only mapping of guest pages.
  */
-static void *legacy_s390_alloc(ram_addr_t size)
+static void *legacy_s390_alloc(size_t size)
 {
     void *mem;