[Qemu-devel] [PATCH 20/23] s390: move memory calculation into the sclp device

[Cornelia Huck <cornelia.huck@de.ibm.com>]

From: David Hildenbrand <dahi@linux.vnet.ibm.com>

The restrictions for memory calculation belong to the sclp device.

Let's move the calculation to that point, so we are able to unify it for
both s390 machines. The sclp device is the first device to be initialized.
It performs the calculation and safely stores it in the machine, where
other parts of the system can access an reuse it.

The memory hotplug device is now only created when it is really needed.

Reviewed-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c | 54 +++-------------------------------------
 hw/s390x/s390-virtio.c     | 18 +++-----------
 hw/s390x/sclp.c            | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 66 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index d4afe7d..eae1305 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -102,54 +102,16 @@ static void virtio_ccw_register_hcalls(void)
 
 static void ccw_init(MachineState *machine)
 {
-    ram_addr_t my_ram_size = machine->ram_size;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    sclpMemoryHotplugDev *mhd = init_sclp_memory_hotplug_dev();
     int ret;
     VirtualCssBus *css_bus;
     DeviceState *dev;
-    ram_addr_t pad_size = 0;
-    ram_addr_t maxmem = machine->maxram_size;
-    ram_addr_t standby_mem_size = maxmem - my_ram_size;
-    uint64_t kvm_limit;
-
-    /* The storage increment size is a multiple of 1M and is a power of 2.
-     * The number of storage increments must be MAX_STORAGE_INCREMENTS or fewer.
-     * The variable 'mhd->increment_size' is an exponent of 2 that can be
-     * used to calculate the size (in bytes) of an increment. */
-    mhd->increment_size = 20;
-    while ((my_ram_size >> mhd->increment_size) > MAX_STORAGE_INCREMENTS) {
-        mhd->increment_size++;
-    }
-    while ((standby_mem_size >> mhd->increment_size) > MAX_STORAGE_INCREMENTS) {
-        mhd->increment_size++;
-    }
 
-    /* The core and standby memory areas need 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. */
-    standby_mem_size = standby_mem_size >> mhd->increment_size
-                                        << mhd->increment_size;
-    my_ram_size = my_ram_size >> mhd->increment_size
-                              << mhd->increment_size;
-
-    /* let's propagate the changed ram size into the global variable. */
-    ram_size = my_ram_size;
-    machine->maxram_size = my_ram_size + standby_mem_size;
-
-    ret = s390_set_memory_limit(machine->maxram_size, &kvm_limit);
-    if (ret == -E2BIG) {
-        hw_error("qemu: host supports a maximum of %" PRIu64 " GB",
-                 kvm_limit >> 30);
-    } else if (ret) {
-        hw_error("qemu: setting the guest size failed");
-    }
+    s390_sclp_init();
 
     /* get a BUS */
     css_bus = virtual_css_bus_init();
-    s390_sclp_init();
     s390_init_ipl_dev(machine->kernel_filename, machine->kernel_cmdline,
                       machine->initrd_filename, "s390-ccw.img", true);
     s390_flic_init();
@@ -163,21 +125,11 @@ static void ccw_init(MachineState *machine)
     virtio_ccw_register_hcalls();
 
     /* allocate RAM for core */
-    memory_region_init_ram(ram, NULL, "s390.ram", my_ram_size, &error_abort);
+    memory_region_init_ram(ram, NULL, "s390.ram", machine->ram_size,
+                           &error_abort);
     vmstate_register_ram_global(ram);
     memory_region_add_subregion(sysmem, 0, ram);
 
-    /* If the size of ram is not on a MEM_SECTION_SIZE boundary,
-       calculate the pad size necessary to force this boundary. */
-    if (standby_mem_size) {
-        if (my_ram_size % MEM_SECTION_SIZE) {
-            pad_size = MEM_SECTION_SIZE - my_ram_size % MEM_SECTION_SIZE;
-        }
-        my_ram_size += standby_mem_size + pad_size;
-        mhd->pad_size = pad_size;
-        mhd->standby_mem_size = standby_mem_size;
-    }
-
     /* Initialize storage key device */
     s390_skeys_init();
 
diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index b0f339e..c8e4737 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -261,10 +261,9 @@ int gtod_load(QEMUFile *f, void *opaque, int version_id)
 /* PC hardware initialisation */
 static void s390_init(MachineState *machine)
 {
-    ram_addr_t my_ram_size = machine->ram_size;
+    ram_addr_t my_ram_size;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    int increment_size = 20;
     void *virtio_region;
     hwaddr virtio_region_len;
     hwaddr virtio_region_start;
@@ -273,22 +272,11 @@ static void s390_init(MachineState *machine)
         error_report("Memory hotplug not supported by the selected machine.");
         exit(EXIT_FAILURE);
     }
-    /*
-     * The storage increment size is a multiple of 1M and is a power of 2.
-     * The number of storage increments must be MAX_STORAGE_INCREMENTS or
-     * fewer.
-     */
-    while ((my_ram_size >> increment_size) > MAX_STORAGE_INCREMENTS) {
-        increment_size++;
-    }
-    my_ram_size = my_ram_size >> increment_size << increment_size;
-
-    /* let's propagate the changed ram size into the global variable. */
-    ram_size = my_ram_size;
+    s390_sclp_init();
+    my_ram_size = machine->ram_size;
 
     /* get a BUS */
     s390_bus = s390_virtio_bus_init(&my_ram_size);
-    s390_sclp_init();
     s390_init_ipl_dev(machine->kernel_filename, machine->kernel_cmdline,
                       machine->initrd_filename, ZIPL_FILENAME, false);
     s390_flic_init();
diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
index b1a62c7..ac582e8 100644
--- a/hw/s390x/sclp.c
+++ b/hw/s390x/sclp.c
@@ -470,20 +470,80 @@ void s390_sclp_init(void)
 
 static void sclp_realize(DeviceState *dev, Error **errp)
 {
+    MachineState *machine = MACHINE(qdev_get_machine());
     SCLPDevice *sclp = SCLP(dev);
     Error *l_err = NULL;
+    uint64_t hw_limit;
+    int ret;
 
     object_property_set_bool(OBJECT(sclp->event_facility), true, "realized",
                              &l_err);
     if (l_err) {
         goto error;
     }
+
+    ret = s390_set_memory_limit(machine->maxram_size, &hw_limit);
+    if (ret == -E2BIG) {
+        error_setg(&l_err, "qemu: host supports a maximum of %" PRIu64 " GB",
+                   hw_limit >> 30);
+        goto error;
+    } else if (ret) {
+        error_setg(&l_err, "qemu: setting the guest size failed");
+        goto error;
+    }
     return;
 error:
     assert(l_err);
     error_propagate(errp, l_err);
 }
 
+static void sclp_memory_init(SCLPDevice *sclp)
+{
+    MachineState *machine = MACHINE(qdev_get_machine());
+    ram_addr_t initial_mem = machine->ram_size;
+    ram_addr_t max_mem = machine->maxram_size;
+    ram_addr_t standby_mem = max_mem - initial_mem;
+    ram_addr_t pad_mem = 0;
+    int increment_size = 20;
+
+    /* The storage increment size is a multiple of 1M and is a power of 2.
+     * The number of storage increments must be MAX_STORAGE_INCREMENTS or fewer.
+     * The variable 'increment_size' is an exponent of 2 that can be
+     * used to calculate the size (in bytes) of an increment. */
+    while ((initial_mem >> increment_size) > MAX_STORAGE_INCREMENTS) {
+        increment_size++;
+    }
+    if (machine->ram_slots) {
+        while ((standby_mem >> increment_size) > MAX_STORAGE_INCREMENTS) {
+            increment_size++;
+        }
+    }
+
+    /* The core and standby memory areas need 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;
+    standby_mem = standby_mem >> increment_size << increment_size;
+
+    /* If the size of ram is not on a MEM_SECTION_SIZE boundary,
+       calculate the pad size necessary to force this boundary. */
+    if (machine->ram_slots && standby_mem) {
+        sclpMemoryHotplugDev *mhd = init_sclp_memory_hotplug_dev();
+
+        if (initial_mem % MEM_SECTION_SIZE) {
+            pad_mem = MEM_SECTION_SIZE - initial_mem % MEM_SECTION_SIZE;
+        }
+        mhd->increment_size = increment_size;
+        mhd->pad_size = pad_mem;
+        mhd->standby_mem_size = standby_mem;
+    }
+    machine->ram_size = initial_mem;
+    machine->maxram_size = initial_mem + pad_mem + standby_mem;
+    /* let's propagate the changed ram size into the global variable. */
+    ram_size = initial_mem;
+}
+
 static void sclp_init(Object *obj)
 {
     SCLPDevice *sclp = SCLP(obj);
@@ -495,6 +555,8 @@ static void sclp_init(Object *obj)
     qdev_set_parent_bus(DEVICE(new), sysbus_get_default());
     object_unref(new);
     sclp->event_facility = EVENT_FACILITY(new);
+
+    sclp_memory_init(sclp);
 }
 
 static void sclp_class_init(ObjectClass *oc, void *data)
-- 
2.5.1