From: Gonglei <arei.gong...@huawei.com> Root ports and downstream ports of switches are the hot pluggable ports in a PCI Express hierarchy. PCI Express supports chip-to-chip interconnect, a PCIe link can only connect one pci device/Switch/EndPoint or PCI-bridge.
7.3. Configuration Transaction Rules (PCI Express specification 3.0) 7.3.1. Device Number Downstream Ports that do not have ARI Forwarding enabled must associate only Device 0 with the device attached to the Logical Bus representing the Link from the Port. In QEMU, ARI Forwarding is enabled defualt at emulation of PCIe ports. ARI Forwarding enable setting at firmware/OS Control handoff. If the bit is Set when a non-ARI Device is present, the non-ARI Device can respond to Configuration Space accesses under what it interprets as being different Device Numbers, and its Functions can be aliased under multiple Device Numbers, generally leading to undesired behavior. So, for pci devices attached in pcie root ports or downstream pots, we shoud assure that its slot is non-zero. For pcie devcies, which ARP capbility is not enabled, we also should assure that its slot is non-zero. Changes since v2: - make patch 1/3 more simpler and safer.(Hu Tao) - change check logic from pci.c to pcie.c and change function's name - judge devcies' ARI capbility instead of PCIe ports' ARI Forwarding (Michael) - add trivial patch 3/3 - update patch's commit messages and code comments. Thanks for your reviewing. Changes since v1: - using object_dynamic_cast() instead of simple string comparing (Paolo) - add ARI Forwarding enable bit check - using pcie_cap_get_type() instead of simple string comparing (Marcel) - fix some other comments. Gonglei (3): qdev: Introduce a function to get qbus's parent pcie: add check for ari capability of pcie devices pcie: remove confused comments hw/core/qdev.c | 9 ++++++++ hw/pci/pci.c | 4 ++++ hw/pci/pcie.c | 59 +++++++++++++++++++++++++++++++++++++++++++------- include/hw/pci/pcie.h | 1 + include/hw/qdev-core.h | 1 + 5 files changed, 66 insertions(+), 8 deletions(-) -- 1.7.12.4
