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

[Alexander Graf]

On 06/06/2012 02:05 PM, Jens Freimann wrote:

From: Nick Wang<jfw...@us.ibm.com>

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<jfw...@us.ibm.com>
Signed-off-by: Jens Freimann<jf...@linux.vnet.ibm.com>

Any references to documentation for this one? :)


Alex

---
  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);