[patch V2 00/46] x86, PCI, XEN, genirq ...: Prepare for device MSI

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

This is the second version of providing a base to support device MSI (non
PCI based) and on top of that support for IMS (Interrupt Message Storm)
based devices in a halfways architecture independent way.

The first version can be found here:

    https://lore.kernel.org/r/20200821002424.119492231@xxxxxxxxxxxxx

It's still a mixed bag of bug fixes, cleanups and general improvements
which are worthwhile independent of device MSI.

There are quite a bunch of issues to solve:

  - X86 does not use the device::msi_domain pointer for historical reasons
    and due to XEN, which makes it impossible to create an architecture
    agnostic device MSI infrastructure.

  - X86 has it's own msi_alloc_info data type which is pointlessly
    different from the generic version and does not allow to share code.

  - The logic of composing MSI messages in an hierarchy is busted at the
    core level and of course some (x86) drivers depend on that.

  - A few minor shortcomings as usual

This series addresses that in several steps:

 1) Accidental bug fixes

      iommu/amd: Prevent NULL pointer dereference

 2) Janitoring

      x86/init: Remove unused init ops
      PCI: vmd: Dont abuse vector irqomain as parent
      x86/msi: Remove pointless vcpu_affinity callback

 3) Sanitizing the composition of MSI messages in a hierarchy
 
      genirq/chip: Use the first chip in irq_chip_compose_msi_msg()
      x86/msi: Move compose message callback where it belongs

 4) Simplification of the x86 specific interrupt allocation mechanism

      x86/irq: Rename X86_IRQ_ALLOC_TYPE_MSI* to reflect PCI dependency
      x86/irq: Add allocation type for parent domain retrieval
      iommu/vt-d: Consolidate irq domain getter
      iommu/amd: Consolidate irq domain getter
      iommu/irq_remapping: Consolidate irq domain lookup

 5) Consolidation of the X86 specific interrupt allocation mechanism to be as 
close
    as possible to the generic MSI allocation mechanism which allows to get rid
    of quite a bunch of x86'isms which are pointless

      x86/irq: Prepare consolidation of irq_alloc_info
      x86/msi: Consolidate HPET allocation
      x86/ioapic: Consolidate IOAPIC allocation
      x86/irq: Consolidate DMAR irq allocation
      x86/irq: Consolidate UV domain allocation
      PCI/MSI: Rework pci_msi_domain_calc_hwirq()
      x86/msi: Consolidate MSI allocation
      x86/msi: Use generic MSI domain ops

  6) x86 specific cleanups to remove the dependency on arch_*_msi_irqs()

      x86/irq: Move apic_post_init() invocation to one place
      x86/pci: Reducde #ifdeffery in PCI init code
      x86/irq: Initialize PCI/MSI domain at PCI init time
      irqdomain/msi: Provide DOMAIN_BUS_VMD_MSI
      PCI: vmd: Mark VMD irqdomain with DOMAIN_BUS_VMD_MSI
      PCI/MSI: Provide pci_dev_has_special_msi_domain() helper
      x86/xen: Make xen_msi_init() static and rename it to xen_hvm_msi_init()
      x86/xen: Rework MSI teardown
      x86/xen: Consolidate XEN-MSI init
      irqdomain/msi: Allow to override msi_domain_alloc/free_irqs()
      x86/xen: Wrap XEN MSI management into irqdomain
      iommm/vt-d: Store irq domain in struct device
      iommm/amd: Store irq domain in struct device
      x86/pci: Set default irq domain in pcibios_add_device()
      PCI/MSI: Make arch_.*_msi_irq[s] fallbacks selectable
      x86/irq: Cleanup the arch_*_msi_irqs() leftovers
      x86/irq: Make most MSI ops XEN private
      iommu/vt-d: Remove domain search for PCI/MSI[X]
      iommu/amd: Remove domain search for PCI/MSI

  7) X86 specific preparation for device MSI

      x86/irq: Add DEV_MSI allocation type
      x86/msi: Rename and rework pci_msi_prepare() to cover non-PCI MSI

  8) Generic device MSI infrastructure
      platform-msi: Provide default irq_chip:: Ack
      genirq/proc: Take buslock on affinity write
      genirq/msi: Provide and use msi_domain_set_default_info_flags()
      platform-msi: Add device MSI infrastructure
      irqdomain/msi: Provide msi_alloc/free_store() callbacks

  9) POC of IMS (Interrupt Message Storm) irq domain and irqchip
     implementations for both device array and queue storage.

      irqchip: Add IMS (Interrupt Message Storm) driver - NOT FOR MERGING

Changes vs. V1:

   - Addressed various review comments and addressed the 0day fallout.
     - Corrected the XEN logic (Jürgen)
     - Make the arch fallback in PCI/MSI opt-in not opt-out (Bjorn)

   - Fixed the compose MSI message inconsistency

   - Ensure that the necessary flags are set for device SMI

   - Make the irq bus logic work for affinity setting to prepare
     support for IMS storage in queue memory. It turned out to be
     less scary than I feared.

   - Remove leftovers in iommu/intel|amd

   - Reworked the IMS POC driver to cover queue storage so Jason can have a
     look whether that fits the needs of MLX devices.

The whole lot is also available from git:

   git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git device-msi

This has been tested on Intel/AMD/KVM but lacks testing on:

    - HYPERV (-ENODEV)
    - VMD enabled systems (-ENODEV)
    - XEN (-ENOCLUE)
    - IMS (-ENODEV)

    - Any non-X86 code which might depend on the broken compose MSI message
      logic. Marc excpects not much fallout, but agrees that we need to fix
      it anyway.

#1 - #3 should be applied unconditionally for obvious reasons
#4 - #6 are wortwhile cleanups which should be done independent of device MSI

#7 - #8 look promising to cleanup the platform MSI implementation
        independent of #8, but I neither had cycles nor the stomach to
        tackle that.

#9      is obviously just for the folks interested in IMS

Thanks,

        tglx