Re: [kvm-unit-tests PATCH v4 2/2] s390x: sclp: Implement SCLP_RC_INSUFFICIENT_SCCB_LENGTH

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Tue, 30 May 2023 14:52:43 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:

> If SCLP_CMDW_READ_SCP_INFO fails due to a short buffer, retry
> with a greater buffer.

the idea is good, but I wonder if the code can be simplified (see below)

> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
>  lib/s390x/sclp.c | 58 +++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 50 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
> index 34a31da..9d51ca4 100644
> --- a/lib/s390x/sclp.c
> +++ b/lib/s390x/sclp.c
> @@ -17,13 +17,14 @@
>  #include "sclp.h"
>  #include <alloc_phys.h>
>  #include <alloc_page.h>
> +#include <asm/facility.h>
>  
>  extern unsigned long stacktop;
>  
>  static uint64_t storage_increment_size;
>  static uint64_t max_ram_size;
>  static uint64_t ram_size;
> -char _read_info[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
> +char _read_info[2 * PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

this is ok ^

[skip everything else]

>  void sclp_read_info(void)
>  {
> -	sclp_read_scp_info((void *)_read_info, SCCB_SIZE);

	sclp_read_scp_info((void *)_read_info,
		test_facility(140) ? sizeof(_read_info) : SCCB_SIZE;

> +	sclp_read_scp_info((void *)_read_info);
>  	read_info = (ReadInfo *)_read_info;
>  }
>