From: Wei Xu <address@hidden>
Code base:
https://github.com/Whishay/qemu.git
rfc v3 -> v1
- migration support for both userspace and vhost-net, need tweak vhost
ioctl() to make it work(the code is pasted in the commit message of
vhost migration patch #13).
Note:
the high 32-bit guest feature bit is saved as a subsection for
virtio devices which makes packed ring feature bit check unusable when
loading the saved per-queue variables(this is done before loading
subsection which is the last action for device during migration),
so I save and load all the things generally for now, any idea to fix this?
- Fixed comments from Jason for rfc v3 sorted by patch #, two comments I
didn't take were(from patch) listed here:
09: - introduce new API(virtqueue_fill_n()).
- Didn't take it since userspace backend does not support batching,
so only one element is popped and current API should be enough.
06 & 07: Refactor split and packed pop()/get_avail_bytes().
- the duplicated code interwined with split/packed ring specific
things and it might make it unclear, so I only extracted the few
common parts out side rcu and keep the others separate.
The other revised comments:
02: - reuse current 'avail/used' for 'driver/device' in VRingMemoryRegionCache.
- remove event_idx since shadow_avail_idx works.
03: - move size recalculation to a separate patch.
- keep 'avail/used' in current calculation function name.
- initialize 'desc' memory region as 'false' for 1.0('true' for 1.1)
04: - delete 'event_idx'
05: - rename 'wc' to wrap_counter.
06: - converge common part outside rcu section for 1.0/1.1.
- move memory barrier for the first 'desc' in between checking flag
and read other fields.
- remove unnecessary memory barriers for indirect descriptors.
- no need to destroy indirect memory cache since it is generally done
before return from the function.
- remove redundant maximum chained descriptors limitation check.
- there are some differences(desc name, wrap idx/counter, flags) between
split and packed rings, so keep them separate for now.
- amend the comment when recording index and wrap counter for a kick
from guest.
07: - calculate fields in descriptor instead of read it when filling.
- put memory barrier correctly before filling the flags in descriptor.
- replace full memory barrier with a write barrier in fill.
- shift to read descriptor flags and descriptor necessarily and
separately in packed_pop().
- correct memory barrier in packed_pop() as in packed_fill().
08: - reuse 'shadow_avail_idx' instead of adding a new 'event_idx'.
- use the compact and verified vring_packed_need_event()
version for vhost net/user.
12: - remove the odd cherry-pick comment.
- used bit '15' for wrap_counters.
rfc v2->v3
- addressed performance issue
- fixed feedback from v2
rfc v1->v2
- sync to tiwei's v5
- reuse memory cache function with 1.0
- dropped detach patch and notification helper(04 & 05 in v1)
- guest virtio-net driver unload/reload support
- event suppression support(not tested)
- addressed feedback from v1
Wei Xu (15):
virtio: introduce packed ring definitions
virtio: redefine structure & memory cache for packed ring
virtio: expand offset calculation for packed ring
virtio: add memory region init for packed ring
virtio: init wrap counter for packed ring
virtio: init and desc empty check for packed ring
virtio: get avail bytes check for packed ring
virtio: fill/flush/pop for packed ring
virtio: event suppression support for packed ring
virtio-net: fill head desc after done all in a chain
virtio: add userspace migration of packed ring
virtio: add vhost-net migration of packed ring
virtio: packed ring feature bit for userspace backend
vhost: enable packed ring
virtio: enable packed ring via a new command line
VERSION | 2 +-
hw/net/vhost_net.c | 2 +
hw/net/virtio-net.c | 11 +-
hw/virtio/virtio.c | 756 +++++++++++++++++++++++--
include/hw/virtio/virtio.h | 8 +-
include/standard-headers/linux/virtio_config.h | 15 +
include/standard-headers/linux/virtio_ring.h | 43 ++
7 files changed, 783 insertions(+), 54 deletions(-)