From: Juergen Gross <jgross@suse.com>
To: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Wei Liu <wei.liu2@citrix.com>, Chunyan Liu <cyliu@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH 2/3] libxl: add domain config parameter to force start of qemu
Date: Fri, 18 Mar 2016 09:11:43 +0100 [thread overview]
Message-ID: <56EBB83F.7040008@suse.com> (raw)
In-Reply-To: <CAFLBxZb2SEBjEuMb2-U6_5NJ8UcCaXhSQkvULc6Fu5x9aQCu6w@mail.gmail.com>
On 17/03/16 17:06, George Dunlap wrote:
> On Thu, Mar 10, 2016 at 3:00 PM, Juergen Gross <jgross@suse.com> wrote:
>> Today the device model (qemu) is started for a pv domain only in case
>> a device requiring qemu is specified in the domain configuration
>> (qdisk, vfb, channel). If there is no such device the device model
>> isn't started and hence it is possible to add such a device to the
>> domain later.
>>
>> Add a domain configuration parameter to specify the device model is
>> to be started in any case. This will enable adding devices with a
>> qemu based backend later.
>>
>> While the optimal solution would be to start the device model
>> automatically when needed this would require some major rework of
>> libxl at multiple places.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>
> So wait -- what happens now if you try to attach a disk with a qdisk
> backend to a PV guest that didn't start with qemu running?
It won't work (that was my test case for the patch).
> I'd really like to see patch 3 get in, but I'm not really in favor of
> this sort of a user-visible hack, particularly as we have to support
> it in libxl more or less indefinitely.
Hmm, really? We can add a smarter variant later which will start the
device model in case it isn't started yet. Then the new config parameter
could be just ignored.
I didn't do the smart variant as I'm not sure I could set it up in time
for 4.7. I'd be happy to do it with some assistance regarding the async
framework of libxl I'm not at all familiar with.
Juergen
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next prev parent reply other threads:[~2016-03-18 8:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 15:00 [PATCH 0/3] libxl: add support for qemu base pvusb backend Juergen Gross
2016-03-10 15:00 ` [PATCH 1/3] libxl: make libxl__need_xenpv_qemu() operate on domain config Juergen Gross
2016-03-17 16:53 ` George Dunlap
2016-03-18 8:23 ` Juergen Gross
2016-03-10 15:00 ` [PATCH 2/3] libxl: add domain config parameter to force start of qemu Juergen Gross
2016-03-17 16:06 ` George Dunlap
2016-03-18 8:11 ` Juergen Gross [this message]
2016-03-21 14:28 ` George Dunlap
2016-03-21 14:44 ` Juergen Gross
2016-03-10 15:00 ` [PATCH 3/3] libxl: add new pvusb backend "qusb" provided by qemu Juergen Gross
2016-03-17 16:39 ` George Dunlap
2016-03-18 8:22 ` Juergen Gross
2016-03-17 16:55 ` George Dunlap
2016-03-18 8:24 ` Juergen Gross
2016-03-24 20:07 ` Wei Liu
2016-03-25 6:09 ` Juergen Gross
2016-03-29 9:45 ` George Dunlap
2016-03-29 10:35 ` Juergen Gross
2016-03-30 4:43 ` Juergen Gross
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