On Tue, Aug 15, 2023 at 03:28:59AM +0800, Zhu Lingshan wrote: > This seires introduces > 1)a new SUSPEND bit in the device status > Which is used to suspend the device, so that the device states > and virtqueue states are stablized. > > 2)virtqueue state and accessors, to get and set last_avail_idx > and last_used_idx of virtqueues. > > The main usecase of these new facilities is Live Migration. > > Furture work: dirty page tracking and in-flight descriptors. > > This is RFC, this series carries on Jason and Eugenio's pervious work. > > Any comments are welcome.
In order to support stateful devices like virtiofs, virtio-gpu, or virtio-crypto it would be necessary to add device state save/load functionality too. Even virtio-net needs device state save/load functionality if the VMM is not intercepting the stateful controlq. In-flight descriptors can be included in the device state. In fact, the only reason why I think VIRTIO_F_QUEUE_STATE makes sense is for easy integration into existing vhost software stacks. Otherwise we should just define a device state save/load interface along with standard device state serialization for devices where migration interoperability is possible. VIRTIO_F_QUEUE_STATE is a small subset of device state save/load. I think the convenience of integrating into existing vhost software stacks is worth the duplication, but I wanted to mention that this interface will not be enough to live migrate all device types and we'll need something more in the future. Stefan > > Zhu Lingshan (5): > virtio: introduce SUSPEND bit in device status > virtio: introduce vq state as basic facility > virtio: The actions by the device upon SUSPEND > virtqueue: constraints for virtqueue state > virtio-pci: implement VIRTIO_F_QUEUE_STATE > > content.tex | 120 ++++++++++++++++++++++++++++++++++++++++++++++ > transport-pci.tex | 15 ++++++ > 2 files changed, 135 insertions(+) > > -- > 2.35.3 > > > This publicly archived list offers a means to provide input to the > OASIS Virtual I/O Device (VIRTIO) TC. > > In order to verify user consent to the Feedback License terms and > to minimize spam in the list archive, subscription is required > before posting. > > Subscribe: virtio-comment-subscr...@lists.oasis-open.org > Unsubscribe: virtio-comment-unsubscr...@lists.oasis-open.org > List help: virtio-comment-h...@lists.oasis-open.org > List archive: https://lists.oasis-open.org/archives/virtio-comment/ > Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf > List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists > Committee: https://www.oasis-open.org/committees/virtio/ > Join OASIS: https://www.oasis-open.org/join/ >
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