Re: [kvm-devel] [PATCH 5/8] KVM: PVDMA: Update dma_alloc_coherent to make it paravirt-aware

Amit Shah
2007-11-12T12:00:04Z

On Monday 12 November 2007 16:26:37 Muli Ben-Yehuda wrote:
> On Wed, Nov 07, 2007 at 04:21:06PM +0200, Amit Shah wrote:
> > Of all the DMA calls, only dma_alloc_coherent might not actually
> > call dma_ops->alloc_coherent. We make sure that gets called if the
> > device that's being worked on is a PV device
>
> I always thougt that's a mess... the reason it's done this way is that
> Andi Kleen preferred it for some reason at the time. How about trying
> to fix it cleanly so that dma_alloc_coherent always gets called rather
> than adding a hack to work around a hack? It will require auditing all
> of the different x86 dma-ops but I can help with that.

Hmm, nice to know it's like that just because of "not necessary now".

Fixing this along with stacking dma_ops and making 32-bit also dma_ops-ready
will greatly simplify things.

>
> Cheers,
> Muli