From: Wei Liu <wei.liu2@citrix.com>
To: Juergen Gross <jgross@suse.com>
Cc: wei.liu2@citrix.com, stefano.stabellini@eu.citrix.com,
George.Dunlap@eu.citrix.com, ian.jackson@eu.citrix.com,
cyliu@suse.com, xen-devel@lists.xen.org
Subject: Re: [PATCH v3 5/5] libxl: add domain config parameter to force start of qemu
Date: Thu, 24 Mar 2016 20:35:20 +0000 [thread overview]
Message-ID: <20160324203520.GF14940@citrix.com> (raw)
In-Reply-To: <20160324202845.GE14940@citrix.com>
On Thu, Mar 24, 2016 at 08:28:45PM +0000, Wei Liu wrote:
> On Wed, Mar 23, 2016 at 01:24:07PM +0100, Juergen Gross 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 impossible 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>
>
> I can't say I like this.
>
> Libxl can be made smart enough to detect whether starting a device model
> is required (as you already did in previous patch) then start qemu on
> demand.
>
> There is a xen-attach mode in qemu, and libxl already has machinery for
> starting qemu. I suspect what you need to do is refactoring existing
> code and expose the right parameter for qemu. Then you wouldn't need
> this user visible option at all. You would also save the resources for
> always having an idle qemu in toolstack domain.
>
> Let me know if this is to vague.
>
Actually I don't think this is your problem. I would consider this a bug
in libxl for not starting qemu on demand. I can take a stab at it, but
that will need to wait until next release.
I think the functionality you care about can live without this patch,
but I'm not sure if it would become too cumbersome to use.
Wei.
> Wei.
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next prev parent reply other threads:[~2016-03-24 20:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-23 12:24 [PATCH v3 0/5] libxl: add support for qemu base pvusb backend Juergen Gross
2016-03-23 12:24 ` [PATCH v3 1/5] libxl: make libxl__need_xenpv_qemu() operate on domain config Juergen Gross
2016-03-24 20:28 ` Wei Liu
2016-03-25 6:13 ` Juergen Gross
2016-03-23 12:24 ` [PATCH v3 2/5] libxl: add new pvusb backend "qusb" provided by qemu Juergen Gross
2016-03-25 2:23 ` Chun Yan Liu
[not found] ` <56F5119C02000066000C0F24@suse.com>
2016-03-25 6:29 ` Juergen Gross
2016-03-25 6:38 ` Chun Yan Liu
2016-03-23 12:24 ` [PATCH v3 3/5] libxl: add service function to check whether device model is running Juergen Gross
2016-03-24 20:28 ` Wei Liu
2016-03-23 12:24 ` [PATCH v3 4/5] libxl: check for dynamic device model start required Juergen Gross
2016-03-25 2:06 ` Chun Yan Liu
[not found] ` <56F50DC102000066000C0EF4@suse.com>
2016-03-25 6:25 ` Juergen Gross
2016-03-25 6:29 ` Chun Yan Liu
2016-03-23 12:24 ` [PATCH v3 5/5] libxl: add domain config parameter to force start of qemu Juergen Gross
2016-03-24 20:28 ` Wei Liu
2016-03-24 20:35 ` Wei Liu [this message]
2016-03-25 6:20 ` Juergen Gross
2016-03-25 6:16 ` Juergen Gross
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