在 2022/9/27 AM1:18, Bjorn Helgaas 写道: > On Mon, Sep 26, 2022 at 09:31:34PM +0800, Shuai Xue wrote: >> 在 2022/9/23 PM11:54, Jonathan Cameron 写道: >>>> 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. > > 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/ Bjorn and Jonathan, are you happy with this flow? Thank you. Best Regards, Shuai
