Nowadays, it feels more natural to have that code located in
s390_memory_init(), where we also have direct access to the machine
object.

While at it, use the actual RAM size, not the maximum RAM size which
cannot currently be reached without support for any memory devices.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/s390x/s390-virtio-ccw.c | 22 ++++++++++++++++++----
 hw/s390x/sclp.c            | 11 -----------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 57c95786f6..08156f0682 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -121,11 +121,15 @@ static void subsystem_reset(void)
     }
 }
 
-static void s390_memory_init(MemoryRegion *ram)
+static void s390_memory_init(MachineState *machine)
 {
     MemoryRegion *sysmem = get_system_memory();
+    MemoryRegion *ram = machine->ram;
+    uint64_t ram_size = memory_region_size(ram);
+    uint64_t hw_limit;
+    int ret;
 
-    if (!QEMU_IS_ALIGNED(memory_region_size(ram), 1 * MiB)) {
+    if (!QEMU_IS_ALIGNED(ram_size, 1 * MiB)) {
         /*
          * The SCLP cannot possibly expose smaller granularity right now and KVM
          * cannot handle smaller granularity. As we don't support NUMA, the
@@ -136,7 +140,17 @@ static void s390_memory_init(MemoryRegion *ram)
         exit(EXIT_FAILURE);
     }
 
-    /* allocate RAM for core */
+    ret = s390_set_memory_limit(ram_size, &hw_limit);
+    if (ret == -E2BIG) {
+        error_report("host supports a maximum of %" PRIu64 " GB",
+                     hw_limit / GiB);
+        exit(EXIT_FAILURE);
+    } else if (ret) {
+        error_report("setting the guest size failed");
+        exit(EXIT_FAILURE);
+    }
+
+    /* Map the initial memory. Must happen after setting the memory limit. */
     memory_region_add_subregion(sysmem, 0, ram);
 
     /*
@@ -217,7 +231,7 @@ static void ccw_init(MachineState *machine)
     qdev_realize_and_unref(DEVICE(ms->sclp), NULL, &error_fatal);
 
     /* init memory + setup max page size. Required for the CPU model */
-    s390_memory_init(machine->ram);
+    s390_memory_init(machine);
 
     /* init CPUs (incl. CPU model) early so s390_has_feature() works */
     s390_init_cpus(machine);
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index e725dcd5fd..fac09816bf 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -381,10 +381,7 @@ void sclp_service_interrupt(uint32_t sccb)
 /* qemu object creation and initialization functions */
 static void sclp_realize(DeviceState *dev, Error **errp)
 {
-    MachineState *machine = MACHINE(qdev_get_machine());
     SCLPDevice *sclp = SCLP(dev);
-    uint64_t hw_limit;
-    int ret;
 
     /*
      * qdev_device_add searches the sysbus for TYPE_SCLP_EVENTS_BUS. As long
@@ -394,14 +391,6 @@ static void sclp_realize(DeviceState *dev, Error **errp)
     if (!sysbus_realize(SYS_BUS_DEVICE(sclp->event_facility), errp)) {
         return;
     }
-
-    ret = s390_set_memory_limit(machine->maxram_size, &hw_limit);
-    if (ret == -E2BIG) {
-        error_setg(errp, "host supports a maximum of %" PRIu64 " GB",
-                   hw_limit / GiB);
-    } else if (ret) {
-        error_setg(errp, "setting the guest size failed");
-    }
 }
 
 static void sclp_memory_init(SCLPDevice *sclp)
-- 
2.46.0

On 10/09/2024 19.58, David Hildenbrand wrote:
> Nowadays, it feels more natural to have that code located in
> s390_memory_init(), where we also have direct access to the machine
> object.
> 
> While at it, use the actual RAM size, not the maximum RAM size which
> cannot currently be reached without support for any memory devices.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>   hw/s390x/s390-virtio-ccw.c | 22 ++++++++++++++++++----
>   hw/s390x/sclp.c            | 11 -----------
>   2 files changed, 18 insertions(+), 15 deletions(-)

Reviewed-by: Thomas Huth <thuth@redhat.com>