Re: [Qemu-devel] Re: [PATCH 2 of 5] add can_dma/post_dma for direct IO

Jamie Lokier
2008-12-14T17:30:11Z

Anthony Liguori wrote:
> Let me clarify this a bit more. The problem we're trying to address
> today is the encapsulating knowledge of phys_ram_base. We want to
> minimize the amount of code that makes any assumptions about
> phys_ram_base. Your current API still accesses phys_ram_base directly
> in the PCI DMA API. The only real improvement compared to the current
> virtio code is that you properly handle MMIO. This is not just about
> layout but this also includes the fact that in the future, guest memory
> could be discontiguous in QEMU (think memory hotplug).

One little extra thing:

What about PCI DMA to another PCI device, not to RAM?

That's not used very often, but it ought to work.

-- Jamie