Re: [Xen-devel] Few Comments on the Xen SMMU ARM code

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 10 Dec 2014, manish jaggi wrote:
> Based on my experience with PCI passthrough code merging, below are
> some comments:
> Both require a change in code
> 
> a) The current code which is non-pci passthrough requires a devices'
> device tree node to be associated with smmu node, if that device has
> to be assigned to domU.
> 
> In our system there is no platform device which can be passthough. All
> devices (including uart) are enumerated using PCI enumeration.
> So the device tree looks like
> 
> pcie0 {
> }
> 
> smmu {
> mmu-masters = <&pcie0 0x100>;
> }
> 
> When dom0 boots pcie is assigned to dom0 and a stream ID 0x100 is
> created which later conflicts with a valid device enumerated later
> 
> b) Current xen code and linux code used rb_tree with key as dt_node to
> locate a device and its smmu. With an enumerated device there is no
> such thing. So this would not work.
> 
> 
> I need your views how PCI passthrough / Non PCI passthrough code can
> coexist with the two points mentioned above ?

Hello Manish,
it is increasingly difficult to reply to your questions without reading
any patches or well written design documents.  I suggest you send out
your series, then we can move forward from there.

Cheers,

Stefano

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