[Qemu-devel] [PATCH V3 0/6] virtio 1.0 pci optimizations and fixes

[Jason Wang]

Hi all:

This series tries to fix the following issues:

- qemu abort when trying to adjust endianness for zero length eventfd,
  this prevent fast mmio eventfd from being used in ppc. Fixing by
  skip the endianness adjustment for zero length eventfd.
- 1.0 mmio is slow since it was using datamatch eventfd. Fixing this
  by usinng zero length mmio eventfd, then we could get speed up through
  kernel fast mmio bus on ept capable machine.
- 1.0 mmio is slow compared to pio (at least on some
  archs/setups). Fixing this by re-introducing pio notification
  capability. This will be useful for the arch/setups that fast mmio
  does not work.
- Some virtio pci 1.0 fields were not migrated. This will cause
  unexpected behaviour if migrate during driver initialization. Fixing
  this by introduce a transport specific callback and get/put
  transport specific fields for virtio 1.0.
- queue_enable read was broken. Fixing by set the queue_enable to true
  during guest write and clear it during reset.

Please review.
Thanks

Changes from V2:
- rebase to master
- conditionally use zero length io eventfd based on new kvm cap
- replace "modern_state" with "extra_state" in patch 1
- check for the existence of k->load_extra_state in patch 1

Changes from V1:
- skip zero length eventfd endianness adjustment
- don't use pci specific name ("modern") in virtio core, using "extra"
  instead and in virtio pci callback, using subsections which could
  allow us to extend the future improvement without changing the core.
- don't check virtio_virtqueue_needed() in virtio_extra_state_needed()
- drop the ppc 2.5 machine type patch
- squash Eduardo's 2.5 machine type patches into this series

Jason Wang (6):
  virtio-pci: fix 1.0 virtqueue migration
  memory: don't try to adjust endianness for zero length eventfd
  KVM: add support for any length io eventfd
  virtio-pci: use zero length mmio eventfd for 1.0 notification cap when
    possible
  virtio-pci: introduce pio notification capability for modern device
  virtio-pci: unbreak queue_enable read

 hw/virtio/virtio-pci.c         | 277 +++++++++++++++++++++++++++++++++++++----
 hw/virtio/virtio-pci.h         |  28 +++--
 hw/virtio/virtio.c             |  58 +++++++++
 include/hw/compat.h            |   4 +
 include/hw/virtio/virtio-bus.h |   3 +
 include/sysemu/kvm.h           |   8 ++
 kvm-all.c                      |   4 +
 kvm-stub.c                     |   1 +
 memory.c                       |   8 +-
 9 files changed, 361 insertions(+), 30 deletions(-)

-- 
2.1.4