Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support

Joerg Roedel
2010-07-15T14:45:35Z

On Thu, Jul 15, 2010 at 07:45:06AM -0500, Anthony Liguori wrote:
> On 07/15/2010 04:10 AM, Joerg Roedel wrote:

>> If this means a seperate interface for device dma accesses and not fold
>> that functionality into the cpu_physical_memory* interface I agree too :-)
>>
> No. PCI devices should never call cpu_physical_memory*.

Fully agreed.

> PCI devices should call pci_memory*.
>
> ISA devices should call isa_memory*.

This is a seperate interface. I like the idea and as you stated below it
has clear advantages, so lets go this way.

> All device memory accesses should go through their respective buses.
> There can be multiple IOMMUs at different levels of the device
> hierarchy. If you don't provide bus-level memory access functions that
> chain through the hierarchy, it's extremely difficult to implement all
> the necessary hooks to perform the translations at different places.

Joerg