[PATCH V2 0/5] rework on the IRQ hardening of virtio

[Jason Wang]

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 introducing a boolean for
virtqueue callback enabling and toggle it in virtio_device_ready()
and virtio_reset_device(). Then vring_interrupt() can simply check and
return early if the driver is not ready.

Please review.

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 (4):
  virtio: use virtio_reset_device() when possible
  virtio: introduce config op to synchronize vring callbacks
  virtio-pci: implement synchronize_vqs()
  virtio: harden vring IRQ

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

 drivers/virtio/virtio.c            | 20 ++++++++++++++++----
 drivers/virtio/virtio_pci_common.c | 14 ++++++++++++++
 drivers/virtio/virtio_pci_common.h |  2 ++
 drivers/virtio/virtio_pci_legacy.c |  1 +
 drivers/virtio/virtio_pci_modern.c |  2 ++
 drivers/virtio/virtio_ring.c       |  9 ++++++++-
 include/linux/virtio.h             |  2 ++
 include/linux/virtio_config.h      | 24 ++++++++++++++++++++++++
 8 files changed, 69 insertions(+), 5 deletions(-)

-- 
2.25.1