[PATCH v4 0/4] Retrieving zPCI specific info with VFIO

Matthew Rosato
2019-09-07T00:14:30Z

Note: These patches by Pierre got lost in the ether a few months back
as he has been unavailable to carry them forward. I've made changes
based upon comments received on his last version.

We define a new configuration entry for VFIO/PCI, VFIO_PCI_ZDEV
to configure access to a zPCI region dedicated for retrieving
zPCI features.

When the VFIO_PCI_ZDEV feature is configured we initialize
a new device region, VFIO_REGION_SUBTYPE_ZDEV_CLP, to hold
the information from the ZPCI device the userland needs to
give to a guest driving the zPCI function.

Note that in the current state we do not use the CLP instructions
to access the firmware but get the information directly from
the zdev device.

-This means that the patch 1, "s390: pci: Exporting access to CLP PCI
function and PCI group" is not used and can be let out of this series
without denying the good working of the other patches.
- But we will need this later, eventually in the next iteration
to retrieve values not being saved inside the zdev structure.
like maxstbl and the PCI supported version

To share the code with arch/s390/pci/pci_clp.c the original functions
in pci_clp.c to query PCI functions and PCI functions group are
modified so that they can be exported.

A new function clp_query_pci() replaces clp_query_pci_fn() and
the previous calls to clp_query_pci_fn() and clp_query_pci_fngrp()
are replaced with calls to zdev_query_pci_fn() and zdev_query_pci_fngrp()
using a zdev pointer as argument.

Changes since v3:
- New patch: define maxstbl
- Remove CLP_UTIL_STR_LEN references from uapi header
- Fix broken ifdef CONFIG_VFIO_PCI_ZDEV
- Change Kconfig option from tristate to bool
- Remove VFIO_REGION_TYPE_IBM_ZDEV, move VFIO_REGION_SUBTYPE_ZDEV_CLP to a 1014 subtype
- reject iswrite in .rw callback
- Remove rw restriction on identical buffer sizes
- Allow arbitrary sized read

Pierre Morel (4):
s390: pci: Exporting access to CLP PCI function and PCI group
s390: pci: Define the maxstbl CLP response entry
vfio: zpci: defining the VFIO headers
vfio: pci: Using a device region to retrieve zPCI information

arch/s390/include/asm/pci.h | 3 ++
arch/s390/include/asm/pci_clp.h | 2 +-
arch/s390/pci/pci_clp.c | 71 ++++++++++++++++---------------
drivers/vfio/pci/Kconfig | 7 +++
drivers/vfio/pci/Makefile | 1 +
drivers/vfio/pci/vfio_pci.c | 9 ++++
drivers/vfio/pci/vfio_pci_private.h | 10 +++++
drivers/vfio/pci/vfio_pci_zdev.c | 85 +++++++++++++++++++++++++++++++++++++
include/uapi/linux/vfio.h | 1 +
include/uapi/linux/vfio_zdev.h | 35 +++++++++++++++
10 files changed, 189 insertions(+), 35 deletions(-)
create mode 100644 drivers/vfio/pci/vfio_pci_zdev.c
create mode 100644 include/uapi/linux/vfio_zdev.h

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1.8.3.1