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

Pierre Morel
2019-05-10T08:22:31Z

Using the PCI VFIO interface allows userland, a.k.a. QEMU, to retrieve
ZPCI specific information without knowing Z specific identifiers
like the function ID or the function handle of the zPCI function
hidden behind the PCI interface.

By using the VFIO_IOMMU_GET_INFO ioctl we enter the vfio_iommu_type1
ioctl callback and can insert there the treatment for a new Z specific
capability.

Once in vfio_iommu_type1 we can retrieve the real iommu device,
s390_iommu and call the get_attr iommu operation's callback
in which we can retrieve the zdev device and start clp operations
to retrieve Z specific values the guest driver is concerned with.

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.

These two functions are exported to be used from out of the s390_iommu
code.

Pierre Morel (4):
s390: pci: Exporting access to CLP PCI function and PCI group
vfio: vfio_iommu_type1: Define VFIO_IOMMU_INFO_CAPABILITIES
s390: iommu: Adding get attributes for s390_iommu
vfio: vfio_iommu_type1: implement VFIO_IOMMU_INFO_CAPABILITIES

arch/s390/include/asm/pci.h | 3 ++
arch/s390/pci/pci_clp.c | 72 ++++++++++++++++---------------
drivers/iommu/s390-iommu.c | 77 +++++++++++++++++++++++++++++++++
drivers/vfio/vfio_iommu_type1.c | 95 ++++++++++++++++++++++++++++++++++++++++-
include/linux/iommu.h | 4 ++
include/uapi/linux/vfio.h | 10 +++++
6 files changed, 226 insertions(+), 35 deletions(-)

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2.7.4