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From: Sasha Levin <levinsasha928@gmail.com>
Date: Fri, 9 Nov 2012 15:17:39 -0500
Message-ID: <CA+1xoqd60YihExEuSU2qzsyFRXLS=XaeeX9AaMLhPHggfM6V3A@mail.gmail.com>
Subject: Re: [PATCH v11] kvm: notify host when the guest is panicked
To: Hu Tao <hutao@cn.fujitsu.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>, Marcelo Tosatti <mtosatti@redhat.com>,
        kvm list <kvm@vger.kernel.org>, qemu-devel <qemu-devel@nongnu.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Avi Kivity <avi@redhat.com>,
        "Daniel P. Berrange" <berrange@redhat.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Jan Kiszka <jan.kiszka@siemens.com>, Gleb Natapov <gleb@redhat.com>,
        Blue Swirl <blauwirbel@gmail.com>, Eric Blake <eblake@redhat.com>,
        Andrew Jones <drjones@redhat.com>,
        Luiz Capitulino <lcapitulino@redhat.com>
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On Mon, Nov 5, 2012 at 8:58 PM, Hu Tao <hutao@cn.fujitsu.com> wrote:
> But in the case of panic notification, more dependency means more
> chances of failure of panic notification. Say, if we use a virtio device
> to do panic notification, then we will fail if: virtio itself has
> problems, virtio for some reason can't be deployed(neither built-in or
> as a module), or guest doesn't support virtio, etc.

Add polling to your virtio device. If it didn't notify of a panic but
taking more than 20 sec to answer your poll request you can assume
it's dead.

Actually, just use virtio-serial and something in userspace on the guest.

> We choose IO because compared to virtio device, it is not that heavy and
> less problematic.

Less problematic? Heavy? Are there any known issues with virtio that
should be fixed? You make virtio sound like an old IDE drive or
something.


Thanks,
Sasha
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