[ofa-general] Re: Question about registering the [vdso] memory section in user level

[Dotan Barak]

Roland Dreier wrote:
>     > > > Yes, you can't DMA to VDSO VMA I don't think.
>     > > Why not?  It's just RAM...
>     > Well ... isn't it read-only?
>
> True... you shouldn't be able to DMA to it.  But I assume Dotan is
> trying to register the memory with read-only permission and DMA from
> it.  Dotan, can you be more explicit about what your test is and how
> it fails?
>   
In user level I'm looking at all of the VMAs of the process and try to 
register the last VMA that has
read permission (with ONLY read permission enabled in the MR permissions).

ibv_reg_mr fails for me.
When i added some debug prints i noticed the failure in file: 
uverbs_mem.c function: get_page_shift,
find_vma returned NULL.


Dotan