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

[Alexander Graf <agraf@suse.de>]

On 06/06/2012 02:05 PM, Jens Freimann wrote:
> From: Nick Wang<jfwang@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<jfwang@us.ibm.com>
> Signed-off-by: Jens Freimann<jfrei@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);