[Qemu-devel] [PATCH v3 0/3] add check for PCIe root ports and downstream ports

[arei.gonglei]

From: Gonglei <address@hidden>

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