[patch 00/10] genirq/msi, PCI/MSI: Support for dynamic MSI-X vector expansion - Part 4

[Thomas Gleixner]

This is finally the point where dynamically expanding MSI-X vectors after
enabling MSI-X is implemented.

The first three parts of this work can be found here:

    https://lore.kernel.org/r/20211126222700.862407977@xxxxxxxxxxxxx
    https://lore.kernel.org/r/20211126224100.303046749@xxxxxxxxxxxxx
    https://lore.kernel.org/r/20211126230957.239391799@xxxxxxxxxxxxx

This last and smallest part of the overall series contains the following
changes:

   1) Prepare the core MSI irq domain code to handle range based allocation
      and free

   2) Prepare the PCI/MSI code to handle range based allocation and free
  
   3) Implement a new interface which allows to expand the MSI-X vector
      space after initialization

   4) Enable support for the X86 PCI/MSI irq domains

      This is unfortunate, but some PCI/MSI irq domain implementations,
      e.g. powerpc and the x86/XEN irqdomain wrappers are not really ready
      to support this out of the box.

      I looked at the 30 places which implement PCI/MSI irq domains and
      many of them look like they could support it out of the box, but as
      we have two which definitely don't, making this opt-in is the only
      safe option.

I've tested this by hacking up the XHCI driver and it works like a charm.

There is certainly some more room for consolidating the PCI/MSI-X usage in
drivers, i.e. getting rid of pci_enable_msix*(), but this would have made
this overall series even larger and is an orthogonal issue.

This fourth series is based on:

     git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-3

and also available from git:

     git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git msi-v1-part-4

Thanks,

	tglx
---
 arch/powerpc/platforms/pseries/msi.c |    6 +-
 arch/x86/kernel/apic/msi.c           |    4 -
 arch/x86/pci/xen.c                   |   10 +--
 drivers/base/platform-msi.c          |    3 -
 drivers/pci/msi/irqdomain.c          |   39 ++++++++++----
 drivers/pci/msi/msi.c                |   97 +++++++++++++++++++++++++++--------
 drivers/pci/msi/msi.h                |    4 -
 include/linux/msi.h                  |   46 +++++++++++-----
 include/linux/pci.h                  |   13 ++++
 kernel/irq/msi.c                     |   75 +++++++++++++++------------
 10 files changed, 208 insertions(+), 89 deletions(-)