[PATCH/RFC] vl/s390: fixup ram sizes for compat machines

[Christian Borntraeger]

compat machines did fixup the ram size to match what can be reported via
sclp. We need to mimic those for machines 4.2 and older to not fail on
inbound migration.

Fixes: 3a12fc61af5c ("390x/s390-virtio-ccw: use memdev for RAM")
Reported-by: Lukáš Doktor <address@hidden>
Cc: Igor Mammedov <address@hidden>
Cc: Dr. David Alan Gilbert <address@hidden>
Signed-off-by: David Hildenbrand <address@hidden>
Signed-off-by: Christian Borntraeger <address@hidden>
---
 hw/s390x/s390-virtio-ccw.c | 12 ++++++++++++
 hw/s390x/sclp.c            | 10 ----------
 include/hw/boards.h        |  1 +
 softmmu/vl.c               |  3 +++
 4 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 3cf19c99f3..748c08b157 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -579,6 +579,17 @@ static void s390_nmi(NMIState *n, int cpu_index, Error 
**errp)
     s390_cpu_restart(S390_CPU(cs));
 }
 
+#define MAX_STORAGE_INCREMENTS                  1020
+static ram_addr_t s390_align_ram(ram_addr_t sz)
+{
+    /* same logic as in sclp.c */
+    int increment_size = 20;
+    while ((sz >> increment_size) > MAX_STORAGE_INCREMENTS) {
+        increment_size++;
+    }
+    return sz >> increment_size << increment_size;
+}
+
 static void ccw_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
@@ -808,6 +819,7 @@ static void ccw_machine_4_2_instance_options(MachineState 
*machine)
 static void ccw_machine_4_2_class_options(MachineClass *mc)
 {
     ccw_machine_5_0_class_options(mc);
+    mc->machine_align_ram = s390_align_ram;
     compat_props_add(mc->compat_props, hw_compat_4_2, hw_compat_4_2_len);
 }
 DEFINE_CCW_MACHINE(4_2, "4.2", false);
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index d8ae207731..0a6ff2be82 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -372,16 +372,6 @@ static void sclp_memory_init(SCLPDevice *sclp)
         increment_size++;
     }
     sclp->increment_size = increment_size;
-
-    /* The core memory area needs to be aligned with the increment size.
-     * In effect, this can cause the user-specified memory size to be rounded
-     * down to align with the nearest increment boundary. */
-    initial_mem = initial_mem >> increment_size << increment_size;
-
-    machine->ram_size = initial_mem;
-    machine->maxram_size = initial_mem;
-    /* let's propagate the changed ram size into the global variable. */
-    ram_size = initial_mem;
 }
 
 static void sclp_init(Object *obj)
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 236d239c19..e3574f4b5f 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -218,6 +218,7 @@ struct MachineClass {
                                                          unsigned cpu_index);
     const CPUArchIdList *(*possible_cpu_arch_ids)(MachineState *machine);
     int64_t (*get_default_cpu_node_id)(const MachineState *ms, int idx);
+    ram_addr_t (*machine_align_ram)(ram_addr_t size);
 };
 
 /**
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 1d33a28340..12b5758d12 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2601,6 +2601,9 @@ static bool set_memory_options(uint64_t *ram_slots, 
ram_addr_t *maxram_size,
     }
 
     sz = QEMU_ALIGN_UP(sz, 8192);
+    if (mc->machine_align_ram) {
+        sz = mc->machine_align_ram(sz);
+    }
     ram_size = sz;
     if (ram_size != sz) {
         error_report("ram size too large");
-- 
2.25.1