From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Vrabel <david.vrabel@citrix.com>
Subject: Re: [PATCH RFC 1/4] xen: evtchn: make evtchn_reset()
 ready for soft reset
Date: Thu, 4 Jun 2015 16:19:40 +0100
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To: Tim Deegan <tim@xen.org>, Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>, Keir Fraser <keir@xen.org>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Julien Grall <julien.grall@linaro.org>, Ian Jackson <ian.jackson@eu.citrix.com>, Olaf Hering <olaf@aepfle.de>, David Vrabel <david.vrabel@citrix.com>, Jan Beulich <jbeulich@suse.com>, xen-devel@lists.xenproject.org, Wei Liu <wei.liu2@citrix.com>, Daniel De Graaf <dgdegra@tycho.nsa.gov>
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On 04/06/15 15:05, Tim Deegan wrote:
> At 15:35 +0200 on 03 Jun (1433345719), Vitaly Kuznetsov wrote:
>> We need to close all event channel so the domain performing soft reset
>> will be able to open them back. Interdomain channels are, however,
>> special. We need to keep track of who opened it as in (the most common)
>> case it was opened by the control domain we won't be able (and allowed) to
>> re-establish it.
> 
> 
> I'm not sure I understand -- can you give an example of what this is
> avoiding?  I would have thought that the kexec'ing VM needs to tear
> down _all_ its connections and then restart the ones it wantrs in the
> new OS.

There are some that are in state ECS_UNBOUND (console, xenstore, I
think) at start of day that are allocated on behalf of the domain by the
toolstack.  The kexec'd image will expect them in these same state.

David