** Description changed:
- Description will follow
+ Today, the enumeration of PCI functions on s390x does not reflect which
+ functions belongs to which physical adapter.
+
+ Layout of a PCI function address on Linux:
+ 0000:00:00.0
+ <root complex>:<bus>:<device>.<function>
+
+ On s390x, each function is presented as individual root complex today,
+ e.g.:
+
+ PCHID 0100 VF1 0000:00:00.0
+ PCHID 0100 VF23 0001:00:00.0
+ PCHID 0200 VF1 0002:00:00.0
+ OCHID 0100 VF17 0003:00:00.0
+
+ On other platforms, the addresses correctly reflect the actual HW
+ configuration. Some device drivers (mlx5 for Mellanox adapters) group
+ functions of one physical adapter by checking which PCI functions have
+ identical values for <root complex>:<bus>:<device>. We need to use the
+ same enumeration scheme to achieve this functionality on s390x.
+
+ In this case, the two physical functions of a Mellanox adapter need to
+ get function number 0 and 1, and all virtual functions need to use the
+ same <root complex>:<bus> numbers with function/device numbers counting
+ up.
+
+ Required result (example with 4 VFs per PF):
+
+ PCHID 0100 PF 0 0000:00:00.0
+ PCHID 0100 PF 1 0000:00:00.1
+ PCHID 0100 PF 0 VF 0 0000:00:00.2
+ PCHID 0100 PF 0 VF 1 0000:00:00.3
+ PCHID 0100 PF 0 VF 2 0000:00:00.4
+ PCHID 0100 PF 0 VF 3 0000:00:00.5
+ PCHID 0100 PF 1 VF 0 0000:00:00.6
+ PCHID 0100 PF 1 VF 1 0000:00:00.7
+ PCHID 0100 PF 1 VF 2 0000:00:00.8
+ PCHID 0100 PF 1 VF 3 0000:00:00.9
+
+ PCHID 0200 PF 0 0001:00:00.0
** Also affects: ubuntu-z-systems
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1874056
Title:
[UBUNTU 20.04] s390x/pci: enumerate pci functions per physical adapter
Status in Ubuntu on IBM z Systems:
New
Status in linux package in Ubuntu:
New
Bug description:
Today, the enumeration of PCI functions on s390x does not reflect
which functions belongs to which physical adapter.
Layout of a PCI function address on Linux:
0000:00:00.0
<root complex>:<bus>:<device>.<function>
On s390x, each function is presented as individual root complex today,
e.g.:
PCHID 0100 VF1 0000:00:00.0
PCHID 0100 VF23 0001:00:00.0
PCHID 0200 VF1 0002:00:00.0
OCHID 0100 VF17 0003:00:00.0
On other platforms, the addresses correctly reflect the actual HW
configuration. Some device drivers (mlx5 for Mellanox adapters) group
functions of one physical adapter by checking which PCI functions have
identical values for <root complex>:<bus>:<device>. We need to use the
same enumeration scheme to achieve this functionality on s390x.
In this case, the two physical functions of a Mellanox adapter need to
get function number 0 and 1, and all virtual functions need to use the
same <root complex>:<bus> numbers with function/device numbers
counting up.
Required result (example with 4 VFs per PF):
PCHID 0100 PF 0 0000:00:00.0
PCHID 0100 PF 1 0000:00:00.1
PCHID 0100 PF 0 VF 0 0000:00:00.2
PCHID 0100 PF 0 VF 1 0000:00:00.3
PCHID 0100 PF 0 VF 2 0000:00:00.4
PCHID 0100 PF 0 VF 3 0000:00:00.5
PCHID 0100 PF 1 VF 0 0000:00:00.6
PCHID 0100 PF 1 VF 1 0000:00:00.7
PCHID 0100 PF 1 VF 2 0000:00:00.8
PCHID 0100 PF 1 VF 3 0000:00:00.9
PCHID 0200 PF 0 0001:00:00.0
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