[Qemu-devel] [PATCH v2 4/5] virtio-ccw: Include standby memory when calculating storage increment

[Matthew Rosato]

When determining the memory increment size, use the maxmem size if
it was specified.

Signed-off-by: Matthew Rosato <address@hidden>
---
 hw/s390x/s390-virtio-ccw.c |   42 ++++++++++++++++++++++++++++++++++--------
 target-s390x/cpu.h         |    3 +++
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 0d4f6ae..4877d57 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -17,6 +17,7 @@
 #include "ioinst.h"
 #include "css.h"
 #include "virtio-ccw.h"
+#include "qemu/config-file.h"
 
 void io_subsystem_reset(void)
 {
@@ -84,17 +85,31 @@ static void ccw_init(QEMUMachineInitArgs *args)
     ram_addr_t my_ram_size = args->ram_size;
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    int shift = 0;
+    sclpMemoryHotplugDev *mhd = get_sclp_memory_hotplug_dev();
     uint8_t *storage_keys;
     int ret;
     VirtualCssBus *css_bus;
-
-    /* s390x ram size detection needs a 16bit multiplier + an increment. So
-       guests > 64GB can be specified in 2MB steps etc. */
-    while ((my_ram_size >> (20 + shift)) > 65535) {
-        shift++;
+    QemuOpts *opts = qemu_opts_find(qemu_find_opts("memory-opts"), NULL);
+    ram_addr_t pad_size = 0;
+    ram_addr_t maxmem = qemu_opt_get_size(opts, "maxmem", 0);
+    ram_addr_t standby_mem_size = maxmem - my_ram_size;
+
+    /* The storage increment size is a multiple of 1M and is a power of 2.
+     * The number of storage increments must be 1020 or fewer.
+     * The variable 'mhd->shift' retains the increment size, in the
+     * form of increment_size = (2^shift) MBytes */
+    while ((my_ram_size >> (20 + mhd->shift)) > 1020) {
+        mhd->shift++;
+    }
+    while ((mhd->standby_mem_size >> (20 + mhd->shift)) > 1020) {
+        mhd->shift++;
     }
-    my_ram_size = my_ram_size >> (20 + shift) << (20 + shift);
+
+    /* The core and standby memory areas need to be aligned with
+     * the increment size */
+    standby_mem_size = standby_mem_size >> (20 + mhd->shift)
+                                        << (20 + mhd->shift);
+    my_ram_size = my_ram_size >> (20 + mhd->shift) << (20 + mhd->shift);
 
     /* let's propagate the changed ram size into the global variable. */
     ram_size = my_ram_size;
@@ -109,11 +124,22 @@ static void ccw_init(QEMUMachineInitArgs *args)
     /* register hypercalls */
     virtio_ccw_register_hcalls();
 
-    /* allocate RAM */
+    /* allocate RAM for core */
     memory_region_init_ram(ram, NULL, "s390.ram", my_ram_size);
     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;
+    }
+
     /* allocate storage keys */
     storage_keys = g_malloc0(my_ram_size / TARGET_PAGE_SIZE);
 
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 9673838..8d25fef 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -380,6 +380,9 @@ unsigned s390_del_running_cpu(S390CPU *cpu);
 /* service interrupts are floating therefore we must not pass an cpustate */
 void s390_sclp_extint(uint32_t parm);
 
+/* from s390-virtio-ccw */
+#define MEM_SECTION_SIZE             0x10000000UL
+
 /* from s390-virtio-bus */
 extern const hwaddr virtio_size;
 
-- 
1.7.9.5