Re: [PATCH v3 09/15] KVM: s390: move some gmap shadowing functions away from mm/gmap.c

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

On 1/17/25 8:09 PM, Claudio Imbrenda wrote:
> Move some gmap shadowing functions from mm/gmap.c to kvm/kvm-s390.c and
> the newly created kvm/gmap-vsie.c
> 
> This is a step toward removing gmap from mm.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   arch/s390/include/asm/gmap.h |   9 +-
>   arch/s390/kvm/Makefile       |   2 +-
>   arch/s390/kvm/gmap-vsie.c    | 142 +++++++++++++++++++++
>   arch/s390/kvm/gmap.h         |  20 +++
>   arch/s390/kvm/kvm-s390.c     |  62 ++++++++-
>   arch/s390/kvm/kvm-s390.h     |   2 +
>   arch/s390/kvm/vsie.c         |   2 +
>   arch/s390/mm/gmap.c          | 238 +++++------------------------------
>   8 files changed, 259 insertions(+), 218 deletions(-)
>   create mode 100644 arch/s390/kvm/gmap-vsie.c
[...]
>   /**
>    * gmap_get - increase reference counter for guest address space
> @@ -958,86 +960,40 @@ static int gmap_protect_pte(struct gmap *gmap, unsigned long gaddr,
>    * @prot: indicates access rights: PROT_NONE, PROT_READ or PROT_WRITE
>    * @bits: pgste notification bits to set
>    *
> - * Returns 0 if successfully protected, -ENOMEM if out of memory and
> - * -EFAULT if gaddr is invalid (or mapping for shadows is missing).
> + * Returns:
> + *   PAGE_SIZE if a small page was successfully protected;
> + *   HPAGE_SIZE if a large page was successfully protected;
> + *   -ENOMEM if out of memory;
> + *   -EFAULT if gaddr is invalid (or mapping for shadows is missing);
> + *   -EAGAIN if the guest mapping is missing and should be fixed by the caller.
>    *
> - * Called with sg->mm->mmap_lock in read.
> + * Context: Called with sg->mm->mmap_lock in read.
>    */
> -static int gmap_protect_range(struct gmap *gmap, unsigned long gaddr,
> -			      unsigned long len, int prot, unsigned long bits)
> +int gmap_protect_one(struct gmap *gmap, unsigned long gaddr, int prot, unsigned long bits)
>   {

That's a lot nicer than the nested conditionals that we had before.

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