Re: [PATCH v5 3/4] KVM: s390: Refactor and split some gmap helpers

[Janosch Frank <frankja@linux.ibm.com>]

On 5/28/25 11:55 AM, Claudio Imbrenda wrote:
> Refactor some gmap functions; move the implementation into a separate
> file with only helper functions. The new helper functions work on vm
> addresses, leaving all gmap logic in the gmap functions, which mostly
> become just wrappers.
> 
> The whole gmap handling is going to be moved inside KVM soon, but the
> helper functions need to touch core mm functions, and thus need to
> stay in the core of kernel.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
> Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
> ---

Acked-by: Janosch Frank <frankja@linux.ibm.com>

>   MAINTAINERS                          |   2 +
>   arch/s390/include/asm/gmap.h         |   2 -
>   arch/s390/include/asm/gmap_helpers.h |  15 ++
>   arch/s390/kvm/diag.c                 |  30 +++-
>   arch/s390/kvm/kvm-s390.c             |   5 +-
>   arch/s390/mm/Makefile                |   2 +
>   arch/s390/mm/gmap.c                  | 184 +---------------------
>   arch/s390/mm/gmap_helpers.c          | 221 +++++++++++++++++++++++++++
>   8 files changed, 274 insertions(+), 187 deletions(-)
>   create mode 100644 arch/s390/include/asm/gmap_helpers.h
>   create mode 100644 arch/s390/mm/gmap_helpers.c
> 

[...]

> +#endif /* _ASM_S390_GMAP_HELPERS_H */
> diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
> index 74f73141f9b9..53233dec8cad 100644
> --- a/arch/s390/kvm/diag.c
> +++ b/arch/s390/kvm/diag.c
> @@ -11,12 +11,30 @@
>   #include <linux/kvm.h>
>   #include <linux/kvm_host.h>
>   #include <asm/gmap.h>
> +#include <asm/gmap_helpers.h>
>   #include <asm/virtio-ccw.h>
>   #include "kvm-s390.h"
>   #include "trace.h"
>   #include "trace-s390.h"
>   #include "gaccess.h"
>   
> +static void do_discard_gfn_range(struct kvm_vcpu *vcpu, gfn_t gfn_start, gfn_t gfn_end)
> +{

A helper function for your helper function :)