Hello Boris and Niklas
The patchset I sent to KTML has been rejected during the SRU review since it
modifies code outside the s390x subsystem and that's too risky considering the
patchset goal is hardware enablement for a new mainframe.
If you still want to have this feature on Jammy 5.15 kernel we can try two
things:
1. Upstream the patchset to linux-5.15.y stable tree (I can try to forward it)
2. Reduce the complexity of the patchset and try a new submission on our KTML
Notice also that jammy-hwe kernel (6.8) already includes all the
requested commits
** Changed in: linux (Ubuntu Jammy)
Status: In Progress => Won't Fix
** Changed in: linux (Ubuntu Jammy)
Status: Won't Fix => Deferred
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https://bugs.launchpad.net/bugs/2119650
Title:
[UBUNTU 22.04] PCHID per Port Toleration - IBM z17 Enablement
Status in Ubuntu on IBM z Systems:
In Progress
Status in linux package in Ubuntu:
Fix Committed
Status in linux source package in Jammy:
Deferred
Status in linux source package in Noble:
Fix Released
Status in linux source package in Plucky:
Fix Released
Status in linux source package in Questing:
Fix Committed
Bug description:
[ Impact ]
Improve how s390 kernel discovers and organizes PCI devices, making it
more robust, predictable, and compatible with modern hardware and
virtualization scenarios.
Previously, PCI functions were grouped based on firmware-provided
order and physical channel IDs (PCHIDs), leading to unstable device
numbering and incorrect grouping in complex setups.
The new implementation explicitly sorts PCI functions by Requester ID
(RID) and uses Topology IDs (TIDs) to group multi-function devices,
ensuring deterministic and future-proof bus/domain creation. It fixes
SR-IOV behavior by properly grouping Physical Functions (PFs) and
Virtual Functions (VFs), allowing PFs initially in standby to form
shared domains and treating isolated VFs without a parent PF as
standalone devices.
Parent PF detection has been refactored for consistency, and error
handling has been improved to prevent leaks and crashes when adding
devices dynamically.
[ Fix ]
Backport to Jammy the following commits:
52c79e636a58da s390/pci: make better use of zpci_dbg() levels
0467cdde8c4320 s390/pci: Sort PCI functions prior to creating virtual busses
126034faaac5f3 s390/pci: Use topology ID for multi-function devices
fd1ae23b495b3a PCI: Prefer 'unsigned int' over bare 'unsigned'
c3df83e01a96ca PCI: Clean up pci_scan_slot()
fbed59ed8781d7 PCI: Split out next_ari_fn() from next_fn()
db360b1ea7faef PCI: Move jailhouse's isolated function handling to
pci_scan_slot()
189c6c33ff421d PCI: Extend isolated function probing to s390
960ac362648780 s390/pci: allow zPCI zbus without a function zero
45e5f0c017e0d0 s390/pci: clean up left over special treatment for function
zero
25f39d3dcb48bb s390/pci: Ignore RID for isolated VFs
48796104c864cf s390/pci: Fix leak of struct zpci_dev when zpci_add_device()
fails
dc287e4c9149ab s390/pci: Fix SR-IOV for PFs initially in standby
05793884a1f305 s390/pci: Pull search for parent PF out of
zpci_iov_setup_virtfn()
2844ddbd540fc8 s390/pci: Fix handling of isolated VFs
8691abd3afaadd s390/pci: Fix zpci_bus_is_isolated_vf() for non-VFs
42420c50c68f3e s390/pci: Fix missing check for zpci_create_device() error
return
[ Test Case ]
Testing must be performed on an IBM z17 with Network Express adapters
in direct mode.
Begin by attaching at least one adapter with two PFs, each mapped to a
separate port, and confirm that the kernel groups them correctly into
distinct domains without relying on PCHID ordering.
Next, enable SR-IOV on each PF and verify that child VFs are
discovered, grouped with the correct PFs, and functional. Test with
PFs initially in standby to ensure that shared domains are created
dynamically. Introduce isolated VFs without a visible PF and confirm
they enumerate as standalone devices.
Finally, perform hotplug and removal of both PFs and VFs, checking
that zpci_dev structures are cleaned up correctly without leaks or
crashes.
[ Regression Potential ]
The patchset affects s390 PCI subsystem, in particular:
- device enumeration
- function grouping
- SR-IOV handling
An issue in this code may introduce problems such as incorrect grouping of
PFs and VFs, unstable bus numbering, or failure to associate VFs with their
parent PFs.
[ Other Info ]
The patchset has already been tested by IBM using the following PPA:
- https://launchpad.net/~mpellizzer/+archive/ubuntu/ibm-z
---
Description:
PCHID per port toleration is required by the new IBM z17 machine.
This has already been included in Ubuntu 25.04
(see LP#2095480 : PCHID per Port Toleration).
This toleration item is also needed in Noble and Jammy in order to
support new hardware in both LTS releases.
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