[Qemu-devel] [Bug 1771042] Re: dataplane interrupt handler doesn't support msi

[eric hoffman]

thanks for looking at this Stefan - since I don't have any context of
exactly the kind of environmental issues like threading, the patch
posted here isn't really a suggested fix.

it does in general seem helpful if batched interrupts have the same
delivery semantics as non-deferred.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1771042

Title:
  dataplane interrupt handler doesn't support msi

Status in QEMU:
  New

Bug description:
  hw/block/dataplane/virtio-blk.c commit
  1010cadf62332017648abee0d7a3dc7f2eef9632

  in the function notify_guest_bh, the function virtio_notify_irqfd is called
  to deliver the interrupt corresponding to the vq

  however, without the dataplane, hw/block/virtio_blk_req_complete calls
  virtio_notify to deliver the interrupt (immediately). this goes though
  a slightly more involved path that calls virtio_pci_notify which includes
  a case to handle msi interrupts.

  so, msi interrupts with block devices aren't serviced when using dataplane
  batching.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1771042/+subscriptions