On Tue, 27 Sep 2022 13:13:29 +0800
Shuai Xue [off-list ref] wrote:

在 2022/9/27 AM1:18, Bjorn Helgaas 写道:

quoted

On Mon, Sep 26, 2022 at 09:31:34PM +0800, Shuai Xue wrote:  

quoted

在 2022/9/23 PM11:54, Jonathan Cameron 写道:  

quoted

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I found a similar definition in arch/ia64/pci/pci.c .

	#define PCI_SAL_ADDRESS(seg, bus, devfn, reg)		\
	(((u64) seg << 24) | (bus << 16) | (devfn << 8) | (reg))

Should we move it into a common header first?  

Maybe. The bus, devfn, reg part is standard bdf, but I don't think
the PCI 6.0 spec defined a version with the seg in the upper bits.
I'm not sure if we want to adopt that in LInux.  

I found lots of code use seg,bus,devfn,reg with format "%04x:%02x:%02x.%x",
I am not quite familiar with PCIe spec. What do you think about it, Bjorn?  

The PCIe spec defines an address encoding for bus/device/function/reg
for the purposes of ECAM (PCIe r6.0, sec 7.2.2), but as far as I know,
it doesn't define anything similar that includes the segment.  The
segment is really outside the scope of PCIe because each segment is a
completely separate PCIe hierarchy.  

Thank you for your explanation.

quoted

So I probably wouldn't make this a generic definition.  But if/when
you print things like this out, please do use the format spec you
mentioned above so it matches the style used elsewhere.
  

Agree. The print format of bus/device/function/reg is "%04x:%02x:%02x.%x",
so I named the PMU as the same format. Then the usage flow would be:

- lspci to get the device root port in format seg/bus/device/function/reg.
	10:00.0 PCI bridge: Device 1ded:8000 (rev 01)
- select its PMU name pcie_bdf_100000.
- monitor with perf:
	perf stat -a -e pcie_bdf_200/Rx_PCIe_TLP_Data_Payload/

I think you probably want something in there to indicate it's an RP
and the bdf part may be redundant...

Jonathan

Bjorn and Jonathan, are you happy with this flow?

Thank you.

Best Regards,
Shuai

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