Re: [Xen-devel] [PATCH 10/22] xen/arm: p2m: Differentiate cacheable vs non-cacheable MMIO

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 20 Jul 2016, Julien Grall wrote:
> Currently, the p2m type p2m_mmio_direct is used to map in stage-2
> cacheable MMIO (via map_regions_rw_cache) and non-cacheable one (via
> map_mmio_regions). The p2m code is relying on the caller to give the
> correct memory attribute.
> 
> In a follow-up patch, the p2m code will rely on the p2m type to find the
> correct memory attribute. In preparation of this, introduce
> p2m_mmio_direct_nc and p2m_mimo_direct_c to differentiate the
> cacheability of the MMIO.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


>  xen/arch/arm/p2m.c        | 7 ++++---
>  xen/include/asm-arm/p2m.h | 3 ++-
>  2 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 99be9be..999de2b 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -272,7 +272,8 @@ static void p2m_set_permission(lpae_t *e, p2m_type_t t, 
> p2m_access_t a)
>      case p2m_iommu_map_rw:
>      case p2m_map_foreign:
>      case p2m_grant_map_rw:
> -    case p2m_mmio_direct:
> +    case p2m_mmio_direct_nc:
> +    case p2m_mmio_direct_c:
>          e->p2m.xn = 1;
>          e->p2m.write = 1;
>          break;
> @@ -1195,7 +1196,7 @@ int map_regions_rw_cache(struct domain *d,
>                           mfn_t mfn)
>  {
>      return p2m_insert_mapping(d, gfn, nr, mfn,
> -                              MATTR_MEM, p2m_mmio_direct);
> +                              MATTR_MEM, p2m_mmio_direct_c);
>  }
>  
>  int unmap_regions_rw_cache(struct domain *d,
> @@ -1212,7 +1213,7 @@ int map_mmio_regions(struct domain *d,
>                       mfn_t mfn)
>  {
>      return p2m_insert_mapping(d, start_gfn, nr, mfn,
> -                              MATTR_DEV, p2m_mmio_direct);
> +                              MATTR_DEV, p2m_mmio_direct_nc);
>  }
>  
>  int unmap_mmio_regions(struct domain *d,
> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> index 78d37ab..20a220ea 100644
> --- a/xen/include/asm-arm/p2m.h
> +++ b/xen/include/asm-arm/p2m.h
> @@ -87,7 +87,8 @@ typedef enum {
>      p2m_invalid = 0,    /* Nothing mapped here */
>      p2m_ram_rw,         /* Normal read/write guest RAM */
>      p2m_ram_ro,         /* Read-only; writes are silently dropped */
> -    p2m_mmio_direct,    /* Read/write mapping of genuine MMIO area */
> +    p2m_mmio_direct_nc, /* Read/write mapping of genuine MMIO area 
> non-cacheable */
> +    p2m_mmio_direct_c,  /* Read/write mapping of genuine MMIO area cacheable 
> */
>      p2m_map_foreign,    /* Ram pages from foreign domain */
>      p2m_grant_map_rw,   /* Read/write grant mapping */
>      p2m_grant_map_ro,   /* Read-only grant mapping */
> -- 
> 1.9.1
> 

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