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    Subject[PATCH V6 0/9] rework on the IRQ hardening of virtio
    Date
    Hi All:

    This is a rework on the IRQ hardening for virtio which is done
    previously by the following commits are reverted:

    9e35276a5344 ("virtio_pci: harden MSI-X interrupts")
    080cd7c3ac87 ("virtio-pci: harden INTX interrupts")

    The reason is that it depends on the IRQF_NO_AUTOEN which may conflict
    with the assumption of the affinity managed IRQ that is used by some
    virtio drivers. And what's more, it is only done for virtio-pci but
    not other transports.

    In this rework, I try to implement a general virtio solution which
    borrows the idea of the INTX hardening by re-using per virtqueue
    boolean vq->broken and toggle it in virtio_device_ready() and
    virtio_reset_device(). Then we can simply reuse the existing checks in
    the vring_interrupt() and return early if the driver is not ready.

    Note that, I only did compile test on ccw and MMIO transport.

    Please review.

    Changes since V5:

    - Various tweaks on the comments

    Changes since V4:

    - use spin_lock_irq()/spin_unlock_irq() to synchronize with
    vring_interrupt() for ccw
    - use spin_lock()/spin_unlock() to protect vring_interrupt() for non
    airq
    - add comment to explain the ordering implications of set_status() for
    PCI, ccw and MMIO
    - various tweaks on the comments and changelogs

    Changes since V3:

    - Rename synchornize_vqs() to synchronize_cbs()
    - tweak the comment for synchronize_cbs()
    - switch to use a dedicated helper __virtio_unbreak_device() and
    document it should be only used for probing
    - switch to use rwlock to synchornize the non airq for ccw

    Changes since V2:

    - add ccw and MMIO support
    - rename synchronize_vqs() to synchronize_cbs()
    - switch to re-use vq->broken instead of introducing new device
    attributes for the future virtqueue reset support
    - remove unnecssary READ_ONCE()/WRITE_ONCE()
    - a new patch to remove device triggerable BUG_ON()
    - more tweaks on the comments

    Changes since v1:

    - Use transport specific irq synchronization method when possible
    - Drop the module parameter and enable the hardening unconditonally
    - Tweak the barrier/ordering facilities used in the code
    - Reanme irq_soft_enabled to driver_ready
    - Avoid unnecssary IRQ synchornization (e.g during boot)

    Jason Wang (8):
    virtio: use virtio_reset_device() when possible
    virtio: introduce config op to synchronize vring callbacks
    virtio-pci: implement synchronize_cbs()
    virtio-mmio: implement synchronize_cbs()
    virtio-ccw: implement synchronize_cbs()
    virtio: allow to unbreak virtqueue
    virtio: harden vring IRQ
    virtio: use WARN_ON() to warning illegal status value

    Stefano Garzarella (1):
    virtio: use virtio_device_ready() in virtio_device_restore()

    drivers/s390/virtio/virtio_ccw.c | 34 +++++++++++++++++++
    drivers/virtio/virtio.c | 24 +++++++++----
    drivers/virtio/virtio_mmio.c | 13 +++++++
    drivers/virtio/virtio_pci_legacy.c | 1 +
    drivers/virtio/virtio_pci_modern.c | 2 ++
    drivers/virtio/virtio_pci_modern_dev.c | 5 +++
    drivers/virtio/virtio_ring.c | 33 +++++++++++++++---
    include/linux/virtio.h | 1 +
    include/linux/virtio_config.h | 47 +++++++++++++++++++++++++-
    9 files changed, 148 insertions(+), 12 deletions(-)

    --
    2.25.1

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