Re: [Xen-devel] [RFC for-4.8 4/6] xen/arm: Add helper functions to map RWX memory regions

[Julien Grall <julien.grall@xxxxxxx>]

Hi Edgar,

On 20/05/16 16:51, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxxx>
>
> Create a helper function to map regions as MEMORY with
> cached attributes and read-write-execute permissions.
Providing setting the execute bit is useful, I would try to rationalize 
the helpers by expanding map_regions_rw_cache (and maybe rename it).
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxxxxx>
> ---
>   xen/arch/arm/p2m.c        | 26 ++++++++++++++++++++++++++
>   xen/include/asm-arm/p2m.h | 10 ++++++++++
>   2 files changed, 36 insertions(+)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index db21433..7e788f9 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -1219,6 +1219,32 @@ int p2m_populate_ram(struct domain *d,
>                                d->arch.p2m.default_access);
>   }
>
> +int map_regions_rwx_cache(struct domain *d,
> +                         unsigned long start_gfn,
> +                         unsigned long nr,
> +                         unsigned long mfn)
> +{
> +    return apply_p2m_changes(d, INSERT,
> +                             pfn_to_paddr(start_gfn),
> +                             pfn_to_paddr(start_gfn + nr),
> +                             pfn_to_paddr(mfn),
> +                             MATTR_MEM, 0, p2m_ram_rw,
We should not use p2m_ram_rw for other mapping than DRAM. It could be 
used by Xen to differentiate MMIO vs RAM.
> +                             p2m_access_rwx);
> +}
> +
> +int unmap_regions_rwx_cache(struct domain *d,
> +                           unsigned long start_gfn,
> +                           unsigned long nr,
> +                           unsigned long mfn)
> +{
> +    return apply_p2m_changes(d, REMOVE,
> +                             pfn_to_paddr(start_gfn),
> +                             pfn_to_paddr(start_gfn + nr),
> +                             pfn_to_paddr(mfn),
> +                             MATTR_MEM, 0, p2m_invalid,
> +                             p2m_access_rwx);
> +}
> +
>   int map_regions_rw_cache(struct domain *d,
>                            unsigned long start_gfn,
>                            unsigned long nr,
> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> index d240d1e..294050e 100644
> --- a/xen/include/asm-arm/p2m.h
> +++ b/xen/include/asm-arm/p2m.h
> @@ -144,6 +144,16 @@ int p2m_cache_flush(struct domain *d, xen_pfn_t start_mfn, 
> xen_pfn_t end_mfn);
>   /* Setup p2m RAM mapping for domain d from start-end. */
>   int p2m_populate_ram(struct domain *d, paddr_t start, paddr_t end);
>
> +int map_regions_rwx_cache(struct domain *d,
> +                          unsigned long start_gfn,
> +                          unsigned long nr_mfns,
> +                          unsigned long mfn);
> +
> +int unmap_regions_rwx_cache(struct domain *d,
> +                            unsigned long start_gfn,
> +                            unsigned long nr_mfns,
> +                            unsigned long mfn);
> +
>   int map_regions_rw_cache(struct domain *d,
>                            unsigned long start_gfn,
>                            unsigned long nr_mfns,
Regards,

--
Julien Grall

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