Re: [PATCH v4 2/3] xen/arm: Add p2m_ipa_bits

[Ian Campbell <ian.campbell@citrix.com>]

On Fri, 2015-05-01 at 11:40 +1000, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
> 
> Export p2m_ipa_bits holding the bit size of IPAs used in p2m tables.
> 
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> ---
>  xen/arch/arm/p2m.c        | 5 +++++
>  xen/include/asm-arm/p2m.h | 3 +++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index 8dfee24..c6507ae 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -27,6 +27,9 @@ static unsigned int __read_mostly p2m_root_level;
>  
>  #define P2M_ROOT_PAGES    (1<<P2M_ROOT_ORDER)
>  
> +/* Size of IPAs in bits.  */
> +unsigned int p2m_ipa_bits;

I think this should be __read_mostly.

I'm also wondering about suggesting to put it in the existing #ifdef
with P2M_ROOT_LEVEL etc and have it be:
        const unsigned int __read_mostly = 40
on 32-bit and only vary on 64-bit.

Ian.