[0/2] vhost-user: add message for device reset

Message

Raphael Norwitz Oct. 29, 2019, 9:38 p.m. UTC

I have updated patches [1] sent by David Vrabel last year:

[1] https://lists.gnu.org/archive/html/qemu-devel/2018-03/msg05077.html

This change adds a new “reset device” feature to the vhost-user protocol
and a corresponding VHOST_USER_RESET_DEVICE message to notify vhost-user
backends when a virtio scsi device is reset by a guest.
It also adds support for this new feature/message in vhost-user-scsi.

Now, iff a vhost-user-scsi backend reports that it supports the new
"reset device" feature, QEMU will send a VHOST_USER_RESET_DEVICE
message when the guest resets the virtio device. Existing backends
will be unaffected.

Other types vhost-user backends can benefit from using this new message.
Those built using libvhost-user, for example, rely on the depricated
VHOST_USER_RESET_OWNER message to notify vhost-user backends about
device resets and can be updated to use this new supported message.

Raphael

Raphael Norwitz (2):
  vhost-user: add VHOST_USER_RESET_DEVICE to reset devices
  vhost-user-scsi: reset the device if supported

 docs/interop/vhost-user.rst | 15 +++++++++++++++
 hw/scsi/vhost-user-scsi.c   | 24 ++++++++++++++++++++++++
 hw/virtio/vhost-user.c      |  8 +++++++-
 3 files changed, 46 insertions(+), 1 deletion(-)