Re: [PATCH V3 0/9] rework on the IRQ hardening of virtio

[Jason Wang <jasowang@redhat.com>]

On Mon, Apr 25, 2022 at 10:44 AM Jason Wang <jasowang@redhat.com> wrote:
>
> Hi All:
>

Forgot to add Xuan to the series.

Thanks

> 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 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)
>
> 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
>
> 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/char/virtio_console.c              |  2 +-
>  drivers/crypto/virtio/virtio_crypto_core.c |  2 +-
>  drivers/s390/virtio/virtio_ccw.c           | 31 ++++++++++++++++--
>  drivers/virtio/virtio.c                    | 24 ++++++++++----
>  drivers/virtio/virtio_mmio.c               |  9 +++++
>  drivers/virtio/virtio_pci_common.c         |  2 +-
>  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               | 15 +++++----
>  include/linux/virtio.h                     |  2 +-
>  include/linux/virtio_config.h              | 38 +++++++++++++++++++++-
>  12 files changed, 110 insertions(+), 20 deletions(-)
>
> --
> 2.25.1
>
>