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    Subject[PATCH v6 00/21] KVM: s390: enable zPCI for interpretive execution
    Date
    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.

    Some minor changes are already suggested for the QEMU series, but for
    now the v5 one is still compatible:

    https://lore.kernel.org/kvm/20220404181726.60291-1-mjrosato@linux.ibm.com/

    Changelog v5->v6:
    - Add more R-b tags
    - Address a leak of aift during rmmod kvm (Christian) also destroy the
    associated mutex at this time
    - only need to check nisc match during 2nd insmod of kvm (Pierre)
    - Register for kvm notifier in vfio_pci_zdev open_device, use this to
    trigger GISA (un)registration instead of via iommu_group_for_each_dev
    from virt/kvm/vfio.c (Jason)
    - Since we now always enable the interpretation facilities once a
    passthrough PCI device is detected, let's just set the ECB during
    init vm -- SHM bits will always be used to override load/store
    interpretation
    - Still using KVM_S390_ZPCI_OP for AEN setup/teardown; we can continue
    to discuss alternatives if it makes sense, but wanted to update the
    rest of the series so review can continue.

    Matthew Rosato (21):
    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
    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 | 45 +++
    MAINTAINERS | 1 +
    arch/s390/include/asm/airq.h | 7 +-
    arch/s390/include/asm/kvm_host.h | 18 +
    arch/s390/include/asm/pci.h | 12 +
    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 | 95 ++++-
    arch/s390/kvm/kvm-s390.c | 87 +++-
    arch/s390/kvm/kvm-s390.h | 10 +
    arch/s390/kvm/pci.c | 667 +++++++++++++++++++++++++++++++
    arch/s390/kvm/pci.h | 87 ++++
    arch/s390/pci/pci.c | 15 +
    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/vfio_pci_core.c | 2 +
    drivers/vfio/pci/vfio_pci_zdev.c | 61 ++-
    include/linux/vfio_pci_core.h | 10 +
    include/uapi/linux/kvm.h | 31 ++
    include/uapi/linux/vfio_zdev.h | 7 +
    30 files changed, 1256 insertions(+), 52 deletions(-)
    create mode 100644 arch/s390/kvm/pci.c
    create mode 100644 arch/s390/kvm/pci.h

    --
    2.27.0

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