Re: vhost-user reconnection and crash recovery

[Stefan Hajnoczi]

On Tue, May 11, 2021 at 03:00:05PM +0000, Boeuf, Sebastien wrote:
> But what about the vhost-user backend initialization? Does
> QEMU go again through initializing memory table, vrings, etc...
> since it can't assume anything from the backend?

Yes, the initial protocol messages are the same after reconnection.

In QEMU's vhost-user-blk implementation there is a special code path
involving vhost_dev_get_inflight(). This fetches and restores inflight
virtqueue request state. The restore logic is called by
vhost_user_blk_connect(). Aside from that reconnect is the same as
establishing a new connection.

Stefan

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