[LTP] PCI test of ltp: wrong device was scanned

[yu tian]

Hi,all

I have some questions about PCI testing.
testcases/kernel/device-drivers/pci/tpci_user/tpci.c ->static void
test_run(void)   ,the code scan the devices on a bus one by one,then it
calls pci_scan_slot() in kernel.But A PCIe device has only 8 functions.
Isn’t it possible to scan the next device here?

For example, on the problematic machine:

1. When traversing to the 8.1 device, it will scan to 9.0 by mistake, and
then the kernel will turn 9.0 into a multi-function device (the 9.0 device
is a single-function device)

2. When traversing to the 8.2 device, call pci_rescan_bus in test-case 6 of
the ltp test program to scan all devices on bus 0. At this time, when the
9.0 device is accessed, it is judged to be a multi-function device, and the
subsequent functions are accessed. Before accessing the function, it will
first judge the vendor id. If it is 0xFFFF, it means that the function does
not exist. However, at this time, it is found that the vendor id of 9.1
exists and is the same as 9.0 (it should be 0xffff), so the kernel
recognizes 9.1. Next, I reconfigured 9.1 and assigned its next level of bus
to bus 4. In fact, bus 4 does not exist (the serial port log is as follows)

[ 4218.291890][ 0] ltp_tpci: found pci_dev '0000:00:08.2', bus 0, devfn 66
[ 4218.298560][ 0] ltp_tpci: Bus number: 0 [ 4218.302503][ 0] ltp_tpci:
test-case 1 [ 4218.306232][ 0] ltp_tpci: enable pci device [ 4218.310482][
0] ltp_tpci: enabled pci device [ 4218.314919][ 0] ltp_tpci: test-case 2 [
4218.318679][ 0] ltp_tpci: find bus [ 4218.322164][ 0] ltp_tpci: success
returned bus pointer [ 4218.327538][ 0] ltp_tpci: test-case 3 [
4218.331271][ 0] ltp_tpci: get pci device [ 4218.335266][ 0] ltp_tpci:
found pci device from device info [ 4218.340974][ 0] ltp_tpci: test-case 4
[ 4218.344709][ 0] ltp_tpci: find pci class [ 4218.348740][ 0] ltp_tpci:
found pci device from class number [ 4218.354664][ 0] ltp_tpci: test-case 5
[ 4218.358387][ 0] ltp_tpci: get pci subsys [ 4218.362383][ 0] ltp_tpci:
found pci device from subsys info [ 4218.368070][ 0] ltp_tpci: test-case 6
[ 4218.371802][ 0] ltp_tpci: scan pci bus [ 4218.375816][ 0] pci
0000:00:09.1: [Firmware Bug]: reg 0x10: invalid BAR (can't size) [
4218.384249][ 0] pci 0000:00:09.1: bridge configuration invalid ([bus
00-00]), reconfiguring [ 4218.393594][ 0] pci 0000:00:09.1: PCI bridge to
[bus 04] [ 4218.399043][ 0] pcieport 0000:00:09.1: Device 14:7a19, irq 96 [
4218.405064][ 0] pcieport 0000:00:09.1: Signaling PME with IRQ 133 [
4218.411336][ 1] ltp_tpci: success scan bus [ 4218.415692][ 1] ltp_tpci:
test-case 7 [ 4218.419500][ 1] ltp_tpci: scan pci slot

I think although there may be problems with PCI devices(vendor id of 9.1),
is the ltp test correct?
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