Re: perf/x86/intel/uncore

["Liang, Kan" <kan.liang@linux.intel.com>]

On 1/25/2019 1:54 PM, Song Liu wrote:
> Hi,
> 
> We are debugging an issue that skx_pci_uncores cannot be registered on
> 8-socket system with Xeon Platinum 8176 CPUs. After poking around for a
> while, I found it is caused by snbep_pci2phy_map_init() couldn't find
> a unbox_dev:
> 
>    ubox_dev = pci_get_device(PCI_VENDOR_ID_INTEL, devid, ubox_dev);
>    unbox_dev == NULL
>    ...
> 
> The same kernel (Linus' master) works fine on some single socket SKX
> systems.
> 
> I am not sure what to check next. And I am not sure whether this is
> specific to this system (HPE Superdome Flex).

Could you please share the offset 0xC0 and 0xD4 of the PCI configuration 
space for each device which PCI ID is 0x2014?

snbep_pci2phy_map_init() tries to build a mapping from BUS# to Socket ID.
CPUNODEID (0xc0) discloses the Node ID of current BUS.
GIDNIDMAP (0xd4) discloses the mapping between Socket ID and Node ID.

Here is an example from a 4 socket SKX.
BUS    CPUNODEID(bit2:0)    GIDNIDMAP
0x0    0x0            0x688
0x40    0x1            0x688
0x80    0x2            0x688
0xC0    0x3            0x688


> 
> One thing I noticed is that the PCI configuration space shows
> subsystem vendor ID of 0x1590 instead of 0x8086:
> 
> 0000:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
> 10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 20: 00 00 00 00 00 00 00 00 00 00 00 00 90 15 14 20   << subsystem vendor
> 
> 30: 00 00 00 00 40 00 00 00 00 00 00 00 00 00 00 00
> 
> But I don't think that is the problem as the code search with PCI_ANY_ID.
>

It looks for the device with PCI ID 0x2014.


Thanks,
Kan