On Wed, Nov 28, 2018, 10:08 Russell King - ARM Linux <li...@armlinux.org.uk
wrote:
> >
> > You already cannot do that kmalloc(), exactly because of ERR_PTR().
>
> I'm very sorry, but I think you are confused.
>
> kmalloc() returns a _virtual_ address, which quite rightly must not be
> in the top 4K of 4GB, exactly due to ERR_PTR(). That is fine.
>
> However, that is a completely different kettle of fish from a physical
> or DMA address - neither of which are virtual addresses.
>
You cut away the part that showed that I'm not in the least confused.
Let me just paste it back in here:
"Which is what we ALREADY do for these exact reasons. If the DMA
mappings means that you'd need to add one more page to that list of
reserved pages, then so be it."
So no, I'm not at all confused.
Let me re-iterate: the argument that all addresses have to be dma'able is
garbage.
*Exactly* as with kmalloc and limited virtual addresses, we can limit
physical addresses.
Linus
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
