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Re: [Xen-devel] HVM resumable with -c flag?

To: Mike Sun <msun@xxxxxxxxxx>
Subject: Re: [Xen-devel] HVM resumable with -c flag?
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Fri, 12 Sep 2008 16:42:22 +0100
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On 12/9/08 16:33, "Mike Sun" <msun@xxxxxxxxxx> wrote:

> Sorry if this is a stupid question, but are you saying that all HVM
> guests are now resumable and there no longer needs to be any check for
> that as was done by Brendan Cully's earlier patch requests?

Correct. All HVM PV drivers must support suspend cancellation (i.e.,
resume). And without PV drivers, resume is as simple as just continuing
execution of the guest from where it left off!

> If that's the case, there's something going on for me.  I've tried to
> different HVM guests (a Debian installation and a Damn Small Linux
> Live CD) and after checkpointing, the guests seem to get lodged in a
> strange state.  I can no longer access the guest's console via VNC and
> the state is reported by xend as "------".  Any ideas?

A weird state. My guess is your qemu-dm is not resumable. It used to
consider suspend to be a one-way trip, and kill itself. That's been fixed
quite a long while, but did it work back in 3.1.x? I'm not sure.

Anyway, qemu-dm is where I suggest you investigate first. The guest is most
likely hanging waiting for work to be done by an unresponsive (or
non-existent) qemu_dm process.

 -- Keir

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