Re: [PATCH 0/3] PCI: Unify domain emulation and misc documentation update

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Jul 16, 2025 at 09:08:32AM -0700, Dan Williams wrote:
> Bjorn,
> 
> This is a small collection of miscellaneous updates that originated in
> the PCI/TSM work, but are suitable to go ahead in v6.17. It is a
> documentation update and a new pci_bus_find_emul_domain_nr() helper.
> 
> First, the PCI/TSM work (Trusted Execution Environment Security Manager
> (PCI device assignment for confidential guests)) wants to add some
> additional PCI host bridge sysfs attributes. In preparation for that,
> document what is already there.
> 
> Next, the PCI/TSM effort proposes samples/devsec/ as a reference and
> test implementation of all the TSM infrastructure. It is implemented via
> host bridge emulation and aims to be cross-architecture compatible. It
> stumbled over the current state of PCI domain number emulation being
> arch and driver specific. Remove some of that differentiation and unify
> the existing x86 host bridge emulators (hyper-v and vmd) on a common
> pci_bus_find_emul_domain_nr() helper.
> 
> Dan Williams (3):
>   PCI: Establish document for PCI host bridge sysfs attributes
>   PCI: Enable host bridge emulation for PCI_DOMAINS_GENERIC platforms
>   PCI: vmd: Switch to pci_bus_find_emul_domain_nr()
> 
>  .../ABI/testing/sysfs-devices-pci-host-bridge | 19 +++++++
>  MAINTAINERS                                   |  1 +
>  drivers/pci/controller/pci-hyperv.c           | 53 ++-----------------
>  drivers/pci/controller/vmd.c                  | 33 ++++--------
>  drivers/pci/pci.c                             | 43 ++++++++++++++-
>  drivers/pci/probe.c                           |  8 ++-
>  include/linux/pci.h                           |  4 ++
>  7 files changed, 86 insertions(+), 75 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-devices-pci-host-bridge

Seems OK to me, modulo the conversation with Michael.  Would like a
Reviewed-by from the owners of pci-hyperv.c and vmd.c, of course.

Bjorn