Re: [Xen-devel] RFC: [PATCH 1/3] Enhance platform support for PCI

[Manish Jaggi <mjaggi@xxxxxxxxxxxxxxxxxx>]

On Tuesday 17 March 2015 12:58 PM, Jan Beulich wrote:
> > > > On 17.03.15 at 06:26, <mjaggi@xxxxxxxxxxxxxxxxxx> wrote:
> > In drivers/xen/pci.c on notification BUS_NOTIFY_ADD_DEVICE dom0 issues a
> > hypercall to inform xen that a new pci device has been added.
> > If we were to inform xen about a new pci bus that is added there are  2 ways
> > a) Issue the hypercall from drivers/pci/probe.c
> > b) When a new device is found (BUS_NOTIFY_ADD_DEVICE) issue
> > PHYSDEVOP_pci_device_add hypercall to xen, if xen does not finds that
> > segment number (s_bdf), it will return an error
> > SEG_NO_NOT_FOUND. After that the linux xen code could issue the
> > PHYSDEVOP_pci_host_bridge_add hypercall.
> >
> > I think (b) can be done with minimal code changes. What do you think ?
> I'm pretty sure (a) would even be refused by the maintainers, unless
> there already is a notification being sent. As to (b) - kernel code could
> keep track of which segment/bus pairs it informed Xen about, and
> hence wouldn't even need to wait for an error to be returned from
> the device-add request (which in your proposal would need to be re-
> issued after the host-bridge-add).
Have a query on the CFG space address to be passed as hypercall parameter.
The of_pci_get_host_bridge_resource only parses the ranges property and 
not reg.
reg property has the CFG space address, which is usually stored in 
private pci host controller driver structures.
so pci_dev 's parent pci_bus would not have that info.
One way is to add a method in struct pci_ops but not sure it will be 
accepted or not.
> Jan
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel