[PATCH v8 00/22] KVM: s390: enable zPCI for interpretive execution

[Matthew Rosato]

Note: this version of the series is built on top of vfio -next:
https://github.com/awilliam/linux-vfio/tree/next
As it now depends on 'vfio: remove VFIO_GROUP_NOTIFY_SET_KVM' and its
prereqs.
Additionally, if you care to try testing this series on top of vfio -next
you'll also want to pick up this fix:
https://lore.kernel.org/kvm/20220519182929.581898-1-mjrosato@xxxxxxxxxxxxx/

---

Enable interpretive execution of zPCI instructions + adapter interruption
forwarding for s390x KVM vfio-pci.  This is done by triggering a routine
when the VFIO group is associated with the KVM guest, transmitting to
firmware a special token (GISA designation) to enable that specific guest
for interpretive execution on that zPCI device.  Load/store interpreation
enablement is then controlled by userspace (based upon whether or not a
SHM bit is placed in the virtual function handle).  Adapter Event
Notification interpretation is controlled from userspace via a new KVM
ioctl.

By allowing intepretation of zPCI instructions and firmware delivery of
interrupts to guests, we can reduce the frequency of guest SIE exits for
zPCI.  

>From the perspective of guest configuration, you passthrough zPCI devices
in the same manner as before, with intepretation support being used by
default if available in kernel+qemu.

Will follow up with a link an updated QEMU series.

Changelog v7->v8:
- Fix ioctl documentation (Thomas)
- remove copy_to_user from ioctl, was from old version (Thomas)
- KVM_S390_ZPCIOP_REG_AEN: fail on undefined flags (Thomas)
- kvm_s390_pci_zpci_reg_aen: cleanup hostflag setting (Thomas) and
  also fix an accidental bit inversion while at it
- CONFIG_VFIO_PCI_ZDEV_KVM: add the 'say Y' that was accidentally left
  out of the help text (Jason)
- Restructure the vfio-pci-zdev pieces on top of 'vfio: remove
  VFIO_GROUP_NOTIFY_SET_KVM' (Jason) - open_device/close_device will now
  call the kvm registration routines directly.  Move the open_device call
  to vfio_pci_core_enable so that errors can be propogated.  For parity,
  move the close_device call to vfio_pci_core_disable.

Matthew Rosato (22):
  s390/sclp: detect the zPCI load/store interpretation facility
  s390/sclp: detect the AISII facility
  s390/sclp: detect the AENI facility
  s390/sclp: detect the AISI facility
  s390/airq: pass more TPI info to airq handlers
  s390/airq: allow for airq structure that uses an input vector
  s390/pci: externalize the SIC operation controls and routine
  s390/pci: stash associated GISA designation
  s390/pci: stash dtsm and maxstbl
  vfio/pci: introduce CONFIG_VFIO_PCI_ZDEV_KVM
  KVM: s390: pci: add basic kvm_zdev structure
  KVM: s390: pci: do initial setup for AEN interpretation
  KVM: s390: pci: enable host forwarding of Adapter Event Notifications
  KVM: s390: mechanism to enable guest zPCI Interpretation
  KVM: s390: pci: provide routines for enabling/disabling interrupt
    forwarding
  KVM: s390: pci: add routines to start/stop interpretive execution
  vfio-pci/zdev: add open/close device hooks
  vfio-pci/zdev: add function handle to clp base capability
  vfio-pci/zdev: different maxstbl for interpreted devices
  KVM: s390: add KVM_S390_ZPCI_OP to manage guest zPCI devices
  KVM: s390: introduce CPU feature for zPCI Interpretation
  MAINTAINERS: additional files related kvm s390 pci passthrough

 Documentation/virt/kvm/api.rst   |  46 ++
 MAINTAINERS                      |   1 +
 arch/s390/include/asm/airq.h     |   7 +-
 arch/s390/include/asm/kvm_host.h |  26 ++
 arch/s390/include/asm/pci.h      |  13 +
 arch/s390/include/asm/pci_clp.h  |   9 +-
 arch/s390/include/asm/pci_insn.h |  29 +-
 arch/s390/include/asm/sclp.h     |   4 +
 arch/s390/include/asm/tpi.h      |  13 +
 arch/s390/include/uapi/asm/kvm.h |   1 +
 arch/s390/kvm/Makefile           |   1 +
 arch/s390/kvm/interrupt.c        |  96 ++++-
 arch/s390/kvm/kvm-s390.c         |  87 +++-
 arch/s390/kvm/kvm-s390.h         |  10 +
 arch/s390/kvm/pci.c              | 695 +++++++++++++++++++++++++++++++
 arch/s390/kvm/pci.h              |  88 ++++
 arch/s390/pci/pci.c              |  16 +
 arch/s390/pci/pci_clp.c          |   7 +
 arch/s390/pci/pci_insn.c         |   4 +-
 arch/s390/pci/pci_irq.c          |  48 ++-
 drivers/s390/char/sclp_early.c   |   4 +
 drivers/s390/cio/airq.c          |  12 +-
 drivers/s390/cio/qdio_thinint.c  |   6 +-
 drivers/s390/crypto/ap_bus.c     |   9 +-
 drivers/s390/virtio/virtio_ccw.c |   6 +-
 drivers/vfio/pci/Kconfig         |  11 +
 drivers/vfio/pci/Makefile        |   2 +-
 drivers/vfio/pci/vfio_pci_core.c |  11 +-
 drivers/vfio/pci/vfio_pci_zdev.c |  38 +-
 include/linux/sched/user.h       |   3 +-
 include/linux/vfio_pci_core.h    |  14 +-
 include/uapi/linux/kvm.h         |  32 ++
 include/uapi/linux/vfio_zdev.h   |   7 +
 33 files changed, 1300 insertions(+), 56 deletions(-)
 create mode 100644 arch/s390/kvm/pci.c
 create mode 100644 arch/s390/kvm/pci.h

-- 
2.27.0