[Qemu-devel] [PATCH 8/8] s390: Fix the storage increment size calculation

[Jens Freimann]

From: Nick Wang <address@hidden>

To comply with the SCLP architecture, the number of storage
increments should be 512 or fewer. The increment size is a
multiple of 1M and is a power of 2.

Signed-off-by: Nick Wang <address@hidden>
Signed-off-by: Jens Freimann <address@hidden>
---
 hw/s390-sclp.c   |    2 +-
 hw/s390-virtio.c |    6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/s390-sclp.c b/hw/s390-sclp.c
index 8f45773..3e91f93 100644
--- a/hw/s390-sclp.c
+++ b/hw/s390-sclp.c
@@ -32,7 +32,7 @@ int sclp_read_info(CPUS390XState *env, struct sccb *sccb)
 {
     int shift = 0;
 
-    while ((ram_size >> (20 + shift)) > 65535) {
+    while ((ram_size >> (20 + shift)) > 512) {
         shift++;
     }
     sccb->c.read_info.rnmax = cpu_to_be16(ram_size >> (20 + shift));
diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index 0babf27..9578d15 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -175,9 +175,9 @@ static void s390_init(ram_addr_t my_ram_size,
     int i;
     DeviceState *dev;
 
-    /* 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) {
+    /* The storage increment size is a multiple of 1M and is a power of 2.
+     * The number of storage increments must be 512 or fewer. */
+    while ((my_ram_size >> (20 + shift)) > 512) {
         shift++;
     }
     my_ram_size = my_ram_size >> (20 + shift) << (20 + shift);
-- 
1.7.10.4