RFC: https://lists.nongnu.org/archive/html/qemu-devel/2023-03/msg04263.html
v1: https://lists.nongnu.org/archive/html/qemu-devel/2023-04/msg01575.html v2: https://lists.nongnu.org/archive/html/qemu-devel/2023-07/msg02604.html Hi, I’ve decided not to work on vhost-user SUSPEND/RESUME for now – it is not technically required for virtio-fs migration, which is the actual priority for me now. While we do want to have SUSPEND/RESUME at some point, the only practically existing reason for it is to be able to implement vhost-level resetting in virtiofsd, but that is not related to migration. So one of the changes in v3 is that it no longer depends on the vhost-user SUSPEND/RESUME series, and describes the migration protocol without the device being suspended at any point, but merely that the vrings are stopped. Other changes include: - Patch 1: - Rephrased a lot - Added a description for the VHOST_USER_SET_DEVICE_STATE_FD parameters - Renamed VHOST_USER_PROTOCOL_F_MIGRATORY_STATE to VHOST_USER_PROTOCOL_F_DEVICE_STATE - enum variants changed in value due to dropping the SUSPEND/RESUME dependency - Patch 2: - Pulled in, was a stand-alone patch before - Dropped a sentence about ring state before feature negotiations, as the rings are not to be used during that period anyway - Bit of rephrasing - Patch 3: - Renamed “migratory state” to “device state” - enum variants changed in value due to dropping the SUSPEND/RESUME dependency - Patch 4: - Changed `f` to @f (referencing parameter “f”) in comments - Use g_autofree for the transfer buffer - Note SUSPEND state as a future feature, not currently existing - Wrap read() and write() in RETRY_ON_EINTR() - Patch 5: - Renamed “migratory state” to “device state” - (kept R-b still) Hanna Czenczek (5): vhost-user.rst: Migrating back-end-internal state vhost-user.rst: Clarify enabling/disabling vrings vhost-user: Interface for migration state transfer vhost: Add high-level state save/load functions vhost-user-fs: Implement internal migration docs/interop/vhost-user.rst | 188 ++++++++++++++++++++++- include/hw/virtio/vhost-backend.h | 24 +++ include/hw/virtio/vhost.h | 114 ++++++++++++++ hw/virtio/vhost-user-fs.c | 101 ++++++++++++- hw/virtio/vhost-user.c | 148 ++++++++++++++++++ hw/virtio/vhost.c | 241 ++++++++++++++++++++++++++++++ 6 files changed, 810 insertions(+), 6 deletions(-) -- 2.41.0
