Re: [Qemu-devel] [PATCH v2 1/1] s390x/storage attributes: fix CMMA_BLOCK_SIZE usage

[Cornelia Huck <cohuck@redhat.com>]

On Mon,  2 Jul 2018 15:04:11 +0200
Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> wrote:

> The macro CMMA_BLOCK_SIZE was defined but not used, and a hardcoded
> value was instead used in the code.
> 
> This patch fixes the value of CMMA_BLOCK_SIZE and uses it in the
> appropriate place in the code, and fixes another case of hardcoded
> value in the KVM backend, replacing it with the more appropriate
> constant KVM_S390_CMMA_SIZE_MAX.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
> ---
>  hw/s390x/s390-stattrib-kvm.c | 3 ++-
>  hw/s390x/s390-stattrib.c     | 5 +++--
>  2 files changed, 5 insertions(+), 3 deletions(-)

> diff --git a/hw/s390x/s390-stattrib.c b/hw/s390x/s390-stattrib.c
> index 70b9555..a788cdb 100644
> --- a/hw/s390x/s390-stattrib.c
> +++ b/hw/s390x/s390-stattrib.c
> @@ -20,7 +20,8 @@
>  #include "qapi/error.h"
>  #include "qapi/qmp/qdict.h"
>  
> -#define CMMA_BLOCK_SIZE  (1 << 10)
> +/* 512kB cover 2GB of guest memory */
> +#define CMMA_BLOCK_SIZE  (1 << 19)

Hm, this doesn't apply to current master anymore. Do we want to switch
to something based on the IEC binary prefix definitions here, or keep
the 1 << 19?

>  
>  #define STATTR_FLAG_EOS     0x01ULL
>  #define STATTR_FLAG_MORE    0x02ULL
> @@ -202,7 +203,7 @@ static int cmma_save(QEMUFile *f, void *opaque, int final)
>      S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
>      uint8_t *buf;
>      int r, cx, reallen = 0, ret = 0;
> -    uint32_t buflen = 1 << 19;   /* 512kB cover 2GB of guest memory */
> +    uint32_t buflen = CMMA_BLOCK_SIZE;
>      uint64_t start_gfn = sas->migration_cur_gfn;
>  
>      buf = g_try_malloc(buflen);