Re: [RFC + Queries] Flow of PCI passthrough in ARM

[manish jaggi <manishjaggi.oss@gmail.com>]

On 8 October 2014 20:21, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> On Wed, Oct 08, 2014 at 07:17:48PM +0530, manish jaggi wrote:
>> On 8 October 2014 19:15, Ian Campbell <Ian.Campbell@citrix.com> wrote:
>> > On Wed, 2014-10-08 at 19:07 +0530, manish jaggi wrote:
>> >> Thanks for replying. As detailed in this thread, I need to create a
>> >> hypercall that would send the following information to Xen at the time
>> >> of PCI attach
>> >> { sbdf , domU sbdf, domainId }.
>> >> I am not able to find a way to get the domU sbdf from dom0 at the time
>> >> of pci-attach.
>> >
>> > I think it would need to be done by the pciback driver in the dom0
>> > kernel, which AFAIK is the thing which consistently knows both physical
>> > and virtual sbdf for a given assigned device.
>> >
>> > Ian.
>> >
>> Correct, can you point out which data structure holds the domU sbdf
>> corresponding to the actual sbdf in pciback.
>
> See 'xen_pcibk_export_device' or 'xen_pcibk_publish_pci_root'
> is that what you are referring to?

Xen docs also mention about xen-pciback.passthrough=1. If I set this
in dom0 i see that the device is enumerated as the same sbdf in domU,
but
a) it is not shown in lspci
b) no front-back communication is done for reading devices configuration space
.
Is option useful / fully implemented for ARM ?