Re: [Qemu-devel] [PATCH 00/24] vhost-user reconnect fixes

[Marc-André Lureau]

Hi

On Thu, Jun 23, 2016 at 6:31 AM, Michael S. Tsirkin <address@hidden> wrote:
>
> OK so if it's ok for read or write to fail, then I think
> the callback should just return success.
> This will make sure backends such as vhost net in kernel
> where failure indicates an internal bug are handled
> correctly, while vhost user ignores errors and attempts
> to go on.
>

That's what we are trying to do, but since it's not yet well defined
how to disconnect/reconnect and there are many bugs around this, it
would help a lot to add error checking and error reporting for now.

>> Since there is feature checks on reconnection, qemu should wait for
>> the initial connection feature negotiation to complete. The test added
>> demonstrates this.
>
>
> So on disconnect, we keep the guest going? But then when connect is
> attempted, then we for some reason block guest until negotiation
> is done? Sounds rather strange to me.

When qemu is the server, it already waits for an initial connection
from vhost-user backend. Here it is just enhanced to wait for the
initial nego to complete, which is necessary for proper device
initialization and also further reconnections checks.

-- 
Marc-André Lureau