Re: [Xen-devel] [for-4.11][PATCH v7 08/16] xen/mm: Drop the parameter mfn from populate_pt_range

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 3 Apr 2018, Julien Grall wrote:
> The function populate_pt_range is used to populate in advance the
> page-table but it will not do the actual mapping. So passing the MFN in
> parameter is pointless. Note that the only caller pass 0...
> 
> At the same time replace 0 by INVALID_MFNs. While this does not matter
> as the entry will marked as not valid and populated, INVALID_MFN
> helps the reader to know the MFN is invalid.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> --
> 
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Julien Grall <julien.grall@xxxxxxx>
> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>
> 
>     Changes in v6:
>         - Add George's and Wei's reviewed-by
>         - Add Andrew's acked-by
> 
>     Changes in v5:
>         - Update the commit message to explain why 0 -> INVALID_MFN.
> 
>     Changes in v4:
>         - Patch added.
> ---
>  xen/arch/arm/mm.c    | 5 ++---
>  xen/arch/x86/mm.c    | 5 ++---
>  xen/common/vmap.c    | 2 +-
>  xen/include/xen/mm.h | 3 +--
>  4 files changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 1126e246c0..436df6936b 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -1072,10 +1072,9 @@ int map_pages_to_xen(unsigned long virt,
>      return create_xen_entries(INSERT, virt, _mfn(mfn), nr_mfns, flags);
>  }
>  
> -int populate_pt_range(unsigned long virt, unsigned long mfn,
> -                      unsigned long nr_mfns)
> +int populate_pt_range(unsigned long virt, unsigned long nr_mfns)
>  {
> -    return create_xen_entries(RESERVE, virt, _mfn(mfn), nr_mfns, 0);
> +    return create_xen_entries(RESERVE, virt, INVALID_MFN, nr_mfns, 0);
>  }
>  
>  int destroy_xen_mappings(unsigned long v, unsigned long e)
> diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> index 605f4377fa..6d5f40482e 100644
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -5007,10 +5007,9 @@ int map_pages_to_xen(
>      return 0;
>  }
>  
> -int populate_pt_range(unsigned long virt, unsigned long mfn,
> -                      unsigned long nr_mfns)
> +int populate_pt_range(unsigned long virt, unsigned long nr_mfns)
>  {
> -    return map_pages_to_xen(virt, mfn, nr_mfns, MAP_SMALL_PAGES);
> +    return map_pages_to_xen(virt, mfn_x(INVALID_MFN), nr_mfns, 
> MAP_SMALL_PAGES);
>  }
>  
>  /*
> diff --git a/xen/common/vmap.c b/xen/common/vmap.c
> index 0b23f8fb97..11785ffb0a 100644
> --- a/xen/common/vmap.c
> +++ b/xen/common/vmap.c
> @@ -42,7 +42,7 @@ void __init vm_init_type(enum vmap_region type, void 
> *start, void *end)
>      bitmap_fill(vm_bitmap(type), vm_low[type]);
>  
>      /* Populate page tables for the bitmap if necessary. */
> -    populate_pt_range(va, 0, vm_low[type] - nr);
> +    populate_pt_range(va, vm_low[type] - nr);
>  }
>  
>  static void *vm_alloc(unsigned int nr, unsigned int align,
> diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
> index 142aa73354..538478fa24 100644
> --- a/xen/include/xen/mm.h
> +++ b/xen/include/xen/mm.h
> @@ -175,8 +175,7 @@ int destroy_xen_mappings(unsigned long v, unsigned long 
> e);
>   * Create only non-leaf page table entries for the
>   * page range in Xen virtual address space.
>   */
> -int populate_pt_range(unsigned long virt, unsigned long mfn,
> -                      unsigned long nr_mfns);
> +int populate_pt_range(unsigned long virt, unsigned long nr_mfns);
>  /* Claim handling */
>  unsigned long domain_adjust_tot_pages(struct domain *d, long pages);
>  int domain_set_outstanding_pages(struct domain *d, unsigned long pages);
> -- 
> 2.11.0
> 

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