Re: [Xen-devel] [PATCH 05/11] x86/altp2m: basic data structures and support routines.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.01.15 at 19:49, <edmund.h.white@xxxxxxxxx> wrote:
> On 01/15/2015 08:53 AM, Jan Beulich wrote:
>>>>> On 15.01.15 at 17:48, <tim@xxxxxxx> wrote:
>>> At 13:26 -0800 on 09 Jan (1420806395), Ed White wrote:
>>>> +    /* Init alternate p2m data */
>>>> +    if ( (d->arch.altp2m_eptp = alloc_xenheap_page()) == NULL )
>>>> +    {
>>>> +        rv = -ENOMEM;
>>>> +        goto out;
>>>> +    }
>>>> +    for (i = 0; i < 512; i++)
>>>> +        d->arch.altp2m_eptp[i] = ~0ul;
>>>
>>> This 512 is architectural, I guess?  It should have a named constant.
>> 
>> Perhaps even calculated rather than just defined as a plain
>> number constant, e.g. (PAGE_SIZE / sizeof(something)).
> 
> There are architectural reasons why it's very unlikely to change
> from 512, so I'll just name it if that's OK.

Imo if it's a calculated value (like the number of page table entries
in a page table page is), it should be defined like this. PAGE_SIZE
and the appropriate sizeof() won't change either after all.

Jan


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