Re: [Xen-devel] [PATCH RFC 25/35] arm: acpi add helper functions to map memory regions

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi parth,

Title: this is not acpi specific.

On 04/02/2015 14:02, parth.dixit@xxxxxxxxxx wrote:
> From: Parth Dixit <parth.dixit@xxxxxxxxxx>
>
> For passing ACPI tables to dom0, UEFI memory needs to be mapped
> by xen in dom0 address space. This patch adds helper functions for mapping.
I believe that this is not ACPI/RAM specific. Any cached MMIO regions 
will have same issue.
This because Device memory is too strong and disallow unaligned access.

> Signed-off-by: Parth Dixit <parth.dixit@xxxxxxxxxx>
> ---
>   xen/arch/arm/p2m.c        | 24 ++++++++++++++++++++++++
>   xen/include/asm-arm/p2m.h | 10 ++++++++++
>   2 files changed, 34 insertions(+)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 8809f5a..5593a91 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -943,6 +943,30 @@ int p2m_populate_ram(struct domain *d,
>                                0, MATTR_MEM, p2m_ram_rw);
>   }
>
> +int map_ram_regions(struct domain *d,
> +                     unsigned long start_gfn,
> +                     unsigned long nr,
> +                     unsigned long mfn)
I don't like the name of the function. It gives the impression that we 
map any RAM region to the guest via this function.
Which is obviously wrong and should never be done.

Regards,

--
Julien Grall

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