W dniu 23.01.2023 o 16:15, Shashi Mallela pisze:
sbsa-ref platform with external pcie devices connected to root-port has been simulated and tested in https://linaro.atlassian.net/browse/SRCPC-80 with BSA and similar observations have been made in log file "BSA_with_pcieTests_log.txt".
The topology for pcie devices behind root port or PCIe-PCI bridge could be generated by adding "-device" options to our platform as in https://github.com/qemu/qemu/blob/master/docs/pcie.txt The question is do we need to explicitly add root ports etc in QEMU when we have support for the same via QEMU pcie command options.
I think that sbsa-ref has grown enough to get closer to how real hardware looks like. By default.
I look at pc-q35 as an example of PCI Express based emulated system. There are root ports for built-in hardware because this is how PCI Express looks in real life.
And I am aware that some Arm systems hide root ports and do other nasty tricks around pcie but that's fault of badly designed controllers.
Q35:
$ lspci -t -[0000:00]-+-00.0 +-01.0 Display Controller +-02.0-[01]----00.0 Virtio Ethernet +-02.1-[02]----00.0 USB +-02.2-[03]----00.0 Virtio console +-02.3-[04]----00.0 Virtio scsi storage +-02.4-[05]----00.0 Virtio memory balloon +-02.5-[06]----00.0 Virtio RNG +-02.6-[07]----00.0 Virtio Ethernet +-02.7-[08]-- +-03.0-[09]-- +-03.1-[0a]-- +-03.2-[0b]-- +-03.3-[0c]-- +-03.4-[0d]-- +-03.5-[0e]-- +-1f.0 ISA bridge +-1f.2 SATA controller -1f.3 SMBus