Re: [PATCH 11/22] xen/arm: p2m: Find the memory attributes based on the p2m type

[Julien Grall <julien.grall@arm.com>]

Hi,

On 20/07/16 17:10, Julien Grall wrote:
> Currently, mfn_to_p2m_entry is relying on the caller to provide the
> correct memory attribute and will deduce the sharability based on it.
>
> Some of the callers, such as p2m_create_table, are using same memory
> attribute regardless the underlying p2m type. For instance, this will
> lead to use change the memory attribute from MATTR_DEV to MATTR_MEM when
> a MMIO superpage is shattered.
>
> Furthermore, it makes more difficult to support different shareability
> with the same memory attribute.
>
> All the memory attributes could be deduced via the p2m type. This will
> simplify the code by dropping one parameter.

I just noticed that I forgot to add my Signed-off-by. Stefano, can you 
add my Signed-off-by while committing?

Cheers,

> ---
>     I am not sure whether p2m_direct_mmio_c (cacheable MMIO) should use
>     the outer-shareability or inner-shareability. Any opinions?
> ---
>  xen/arch/arm/p2m.c | 55 ++++++++++++++++++++++++------------------------------
>  1 file changed, 24 insertions(+), 31 deletions(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 999de2b..2f50b4f 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -325,8 +325,7 @@ static void p2m_set_permission(lpae_t *e, p2m_type_t t, p2m_access_t a)
>      }
>  }
>
> -static lpae_t mfn_to_p2m_entry(mfn_t mfn, unsigned int mattr,
> -                               p2m_type_t t, p2m_access_t a)
> +static lpae_t mfn_to_p2m_entry(mfn_t mfn, p2m_type_t t, p2m_access_t a)
>  {
>      /*
>       * sh, xn and write bit will be defined in the following switches
> @@ -335,7 +334,6 @@ static lpae_t mfn_to_p2m_entry(mfn_t mfn, unsigned int mattr,
>      lpae_t e = (lpae_t) {
>          .p2m.af = 1,
>          .p2m.read = 1,
> -        .p2m.mattr = mattr,
>          .p2m.table = 1,
>          .p2m.valid = 1,
>          .p2m.type = t,
> @@ -343,18 +341,21 @@ static lpae_t mfn_to_p2m_entry(mfn_t mfn, unsigned int mattr,
>
>      BUILD_BUG_ON(p2m_max_real_type > (1 << 4));
>
> -    switch (mattr)
> +    switch ( t )
>      {
> -    case MATTR_MEM:
> -        e.p2m.sh = LPAE_SH_INNER;
> +    case p2m_mmio_direct_nc:
> +        e.p2m.mattr = MATTR_DEV;
> +        e.p2m.sh = LPAE_SH_OUTER;
>          break;
>
> -    case MATTR_DEV:
> +    case p2m_mmio_direct_c:
> +        e.p2m.mattr = MATTR_MEM;
>          e.p2m.sh = LPAE_SH_OUTER;
>          break;
> +
>      default:
> -        BUG();
> -        break;
> +        e.p2m.mattr = MATTR_MEM;
> +        e.p2m.sh = LPAE_SH_INNER;
>      }
>
>      p2m_set_permission(&e, t, a);
> @@ -421,7 +422,7 @@ static int p2m_create_table(struct domain *d, lpae_t *entry,
>           */
>           for ( i=0 ; i < LPAE_ENTRIES; i++ )
>           {
> -             pte = mfn_to_p2m_entry(mfn, MATTR_MEM, t, p2m->default_access);
> +             pte = mfn_to_p2m_entry(mfn, t, p2m->default_access);
>
>               mfn = mfn_add(mfn, 1UL << (level_shift - LPAE_SHIFT));
>
> @@ -445,7 +446,7 @@ static int p2m_create_table(struct domain *d, lpae_t *entry,
>
>      unmap_domain_page(p);
>
> -    pte = mfn_to_p2m_entry(_mfn(page_to_mfn(page)), MATTR_MEM, p2m_invalid,
> +    pte = mfn_to_p2m_entry(_mfn(page_to_mfn(page)), p2m_invalid,
>                             p2m->default_access);
>
>      p2m_write_pte(entry, pte, flush_cache);
> @@ -666,7 +667,6 @@ static int apply_one_level(struct domain *d,
>                             paddr_t *addr,
>                             paddr_t *maddr,
>                             bool_t *flush,
> -                           int mattr,
>                             p2m_type_t t,
>                             p2m_access_t a)
>  {
> @@ -695,7 +695,7 @@ static int apply_one_level(struct domain *d,
>                  return rc;
>
>              /* New mapping is superpage aligned, make it */
> -            pte = mfn_to_p2m_entry(_mfn(*maddr >> PAGE_SHIFT), mattr, t, a);
> +            pte = mfn_to_p2m_entry(_mfn(*maddr >> PAGE_SHIFT), t, a);
>              if ( level < 3 )
>                  pte.p2m.table = 0; /* Superpage entry */
>
> @@ -915,7 +915,6 @@ static int apply_p2m_changes(struct domain *d,
>                       gfn_t sgfn,
>                       unsigned long nr,
>                       mfn_t smfn,
> -                     int mattr,
>                       uint32_t mask,
>                       p2m_type_t t,
>                       p2m_access_t a)
> @@ -1054,7 +1053,7 @@ static int apply_p2m_changes(struct domain *d,
>                                    level, flush_pt, op,
>                                    start_gpaddr, end_gpaddr,
>                                    &addr, &maddr, &flush,
> -                                  mattr, t, a);
> +                                  t, a);
>              if ( ret < 0 ) { rc = ret ; goto out; }
>              count += ret;
>
> @@ -1163,7 +1162,7 @@ out:
>           * mapping.
>           */
>          apply_p2m_changes(d, REMOVE, sgfn, gfn - gfn_x(sgfn), smfn,
> -                          mattr, 0, p2m_invalid, d->arch.p2m.default_access);
> +                          0, p2m_invalid, d->arch.p2m.default_access);
>      }
>
>      return rc;
> @@ -1173,10 +1172,10 @@ static inline int p2m_insert_mapping(struct domain *d,
>                                       gfn_t start_gfn,
>                                       unsigned long nr,
>                                       mfn_t mfn,
> -                                     int mattr, p2m_type_t t)
> +                                     p2m_type_t t)
>  {
>      return apply_p2m_changes(d, INSERT, start_gfn, nr, mfn,
> -                             mattr, 0, t, d->arch.p2m.default_access);
> +                             0, t, d->arch.p2m.default_access);
>  }
>
>  static inline int p2m_remove_mapping(struct domain *d,
> @@ -1186,8 +1185,7 @@ static inline int p2m_remove_mapping(struct domain *d,
>  {
>      return apply_p2m_changes(d, REMOVE, start_gfn, nr, mfn,
>                               /* arguments below not used when removing mapping */
> -                             MATTR_MEM, 0, p2m_invalid,
> -                             d->arch.p2m.default_access);
> +                             0, p2m_invalid, d->arch.p2m.default_access);
>  }
>
>  int map_regions_rw_cache(struct domain *d,
> @@ -1195,8 +1193,7 @@ int map_regions_rw_cache(struct domain *d,
>                           unsigned long nr,
>                           mfn_t mfn)
>  {
> -    return p2m_insert_mapping(d, gfn, nr, mfn,
> -                              MATTR_MEM, p2m_mmio_direct_c);
> +    return p2m_insert_mapping(d, gfn, nr, mfn, p2m_mmio_direct_c);
>  }
>
>  int unmap_regions_rw_cache(struct domain *d,
> @@ -1212,8 +1209,7 @@ int map_mmio_regions(struct domain *d,
>                       unsigned long nr,
>                       mfn_t mfn)
>  {
> -    return p2m_insert_mapping(d, start_gfn, nr, mfn,
> -                              MATTR_DEV, p2m_mmio_direct_nc);
> +    return p2m_insert_mapping(d, start_gfn, nr, mfn, p2m_mmio_direct_nc);
>  }
>
>  int unmap_mmio_regions(struct domain *d,
> @@ -1251,8 +1247,7 @@ int guest_physmap_add_entry(struct domain *d,
>                              unsigned long page_order,
>                              p2m_type_t t)
>  {
> -    return p2m_insert_mapping(d, gfn, (1 << page_order), mfn,
> -                              MATTR_MEM, t);
> +    return p2m_insert_mapping(d, gfn, (1 << page_order), mfn, t);
>  }
>
>  void guest_physmap_remove_page(struct domain *d,
> @@ -1412,7 +1407,7 @@ int relinquish_p2m_mapping(struct domain *d)
>      nr = gfn_x(p2m->max_mapped_gfn) - gfn_x(p2m->lowest_mapped_gfn);
>
>      return apply_p2m_changes(d, RELINQUISH, p2m->lowest_mapped_gfn, nr,
> -                             INVALID_MFN, MATTR_MEM, 0, p2m_invalid,
> +                             INVALID_MFN, 0, p2m_invalid,
>                               d->arch.p2m.default_access);
>  }
>
> @@ -1425,8 +1420,7 @@ int p2m_cache_flush(struct domain *d, gfn_t start, unsigned long nr)
>      end = gfn_min(end, p2m->max_mapped_gfn);
>
>      return apply_p2m_changes(d, CACHEFLUSH, start, nr, INVALID_MFN,
> -                             MATTR_MEM, 0, p2m_invalid,
> -                             d->arch.p2m.default_access);
> +                             0, p2m_invalid, d->arch.p2m.default_access);
>  }
>
>  mfn_t gfn_to_mfn(struct domain *d, gfn_t gfn)
> @@ -1827,8 +1821,7 @@ long p2m_set_mem_access(struct domain *d, gfn_t gfn, uint32_t nr,
>      }
>
>      rc = apply_p2m_changes(d, MEMACCESS, gfn_add(gfn, start),
> -                           (nr - start), INVALID_MFN,
> -                           MATTR_MEM, mask, 0, a);
> +                           (nr - start), INVALID_MFN, mask, 0, a);
>      if ( rc < 0 )
>          return rc;
>      else if ( rc > 0 )
>

-- 
Julien Grall

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