Re: [PATCH v5 11/13] xen: introduce xen_alloc/free_coherent_pages

From: Catalin Marinas
Date: Thu Sep 05 2013 - 12:09:59 EST


On Thu, Aug 29, 2013 at 07:32:32PM +0100, Stefano Stabellini wrote:
> xen_swiotlb_alloc_coherent needs to allocate a coherent buffer for cpu
> and devices. On native x86 and ARMv8 is sufficient to call
> __get_free_pages in order to get a coherent buffer, while on ARM we need
> to call arm_dma_ops.alloc.

Don't bet on this for ARMv8. It's not mandated for the architecture, so
at some point some SoC will require non-cacheable buffers for coherency.

--
Catalin
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