[Qemu-devel] [PATCH v1 0/5][RFC] Refactoring of AIS support

[Pierre Morel]

Currently AIS support has several problems:

- AIS support in KVM is reported if KVM has AIS capability.
- Testing if KVM FLIC attributes for AIS are supported does not take into
  account if AIS is supported by KVM.
- KVM report supporting the AIS FLIC features but denies their usage
  if the host kernel does not support the AIS feature.
- Testing if the Adapter interrupt must be suppressed is done looking at the
  ISC and ignores the adapter properties.
- Emulation of PCI devices can only be done with KVM support for AIS.
- Migration of emulated devices can only be done if both side support AIS in KVM

I would like to make some modifications to the code where I think things are
not handled at the right place.

Therefor I propose these changes.
- Use the CPU model to enable AIS in the guest, even without KVM backup
- Ask KVM for AIS support in kvm_flic realize
- add simm/nimm attributes to the KVM FLIC interface to support emulation
  and migration between hosts with and without AIS support in KVM.
- Modify the zPCI VFIO realize function to refuse VFIO PCI devices without
  AIS support in KVM.
- Modify the AIS migration to support emulation and heterogeneous hosts.


Pierre Morel (5):
  s390x/kvm: Enable AIS from CPU model always
  s390x/css: Use AIS AIRQ injection only if adapter support AIS
  s390x/intc: Emulate Adapter Interrupt Suppression
  s390x/pci: Refuse to realize VFIO-PCI if AIS needed but supported
  s390x/intc: AIS is now always migratable

 hw/intc/s390_flic.c     |  3 +-
 hw/intc/s390_flic_kvm.c | 94 ++++++++++++++++++++++++++++++++++++++-----------
 hw/s390x/css.c          |  6 ++--
 hw/s390x/s390-pci-bus.c | 12 +++++++
 target/s390x/kvm.c      |  1 +
 5 files changed, 91 insertions(+), 25 deletions(-)

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2.3.0