[PATCH v3 3/3] PCI: ARM: add support for generic PCI host controller

On Tue, Feb 18, 2014 at 06:59:47PM +0000, Jason Gunthorpe wrote:

On Tue, Feb 18, 2014 at 06:44:20PM +0000, Will Deacon wrote:

quoted

On Tue, Feb 18, 2014 at 06:21:42PM +0000, Jason Gunthorpe wrote:

quoted

On Tue, Feb 18, 2014 at 12:20:43PM +0000, Will Deacon wrote:

quoted

+
+    // BUS_ADDRESS(3)  CPU_PHYSICAL(2)  SIZE(2)
+    ranges = <0x1000000 0x0 0x00000000  0x0 0x00000000  0x0 0x00010000>,

                                           ^^^^^^^^^^^^^^

This probably shouldn't be 0 in the example, nor in your kvm tool
output. For example purposes any value will do.

Hmm, so kvmtool actually provides a PC ioport at 0x0, which is handy since
there's an 8250 down there. That means we have:

0x0    - 0x6200  : Weird PC stuff
0x6200 - 0x10000 : PCI IO space

Should I just change everything to be offset by 0x6200?

Just to be clear, kvm has reserved the first 64k of physical address
space for this IO window? The 0 is fine then, but it isn't typical of
real hardware.

Yup, that's spot on.

Regarding the 0x6200.. There are two conflicting issues there :(
 - You really don't want to let the PCI core assign resources to that
   range, it probably won't work.

Right, with kvmtool we don't support resource assignment (the BARs are fixed)
so everything is PCI_PROBE_ONLY.

 - You probably need that range mapped into the ARM IO window, and the
   PCI driver is the thing doing that

The PCI core already has a black out for low IO ports, I think it
already covers the usual PC suspects so you are probably fine with
what you have for KVM.

Great, so I'll just update the example then. Thanks!

Will