Re: [Xen-devel] [PATCH for 4.5] xen/arm: p2m: Correctly initialize cur_offset

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 10/01/2014 11:33 AM, Ian Campbell wrote:
> On Tue, 2014-09-30 at 15:51 +0100, Julien Grall wrote:
>> {~0,} only initializes the first cell of the array to ~0. The other cells
>> are initialized to 0.
>>
>> Change the initialization to a loop and, at the same time, do the same
>> for the mappings.
> 
> I'm not sure a loop is the best option here vs either { ~0, ~0, ~0, ~0 }
> or a memset, but OK.

Thinking a bit more, we effectively need to initialize only the first 2
cells. It's because the P2M can start either at level 0 or level 1.

Anyway I will use { ~0, ~0, ~0, ~0 }.

> I don't think mappings is wrong as it is though, any reason to change?

{ NULL, } initialize the first cell to NULL and the other to 0.

As NULL is equal to (void *)0 it's fine, but I would prefer if we can
get a rid of this construction.

I would prefer if we do { NULL, NULL, NULL, NULL }.

>> This is fixing boot after 82985d7 "xen: arm: handle variable p2m levels
>> in apply_p2m_changes" on platform where the root-level doesn't have
>> concatenate table (such as the Foundation Model).
> 
> You forgot your S-o-b.

Oh right. I will resend a patch



-- 
Julien Grall

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