Xen nested wiki

Xen nested wiki

[Zhang, Yang Z]

Hi George,

I have updated the Latest Xen nested status in the Xen wiki page, please have a look.
Although it is hard to say nested is good supported or product quality, it is ready to let people to know nested basically is supported by Xen. Especially, for Xen on Xen case, I didn't see any issue with it for more than half of year. Besides, I am always using nested Xen to debug Xen booting issue which doesn't need to reboot my real box. And it really helps me a lot. So, if possible, I hope we can add nested support into Xen 4.4 release to let people know current status.

Xen nested wiki:
http://wiki.xenproject.org/wiki/Xen_nested

best regards
yang

Re: Xen nested wiki

[Dario Faggioli]

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[Adding the Xen publicity mailing list]

On gio, 2014-02-13 at 03:55 +0000, Zhang, Yang Z wrote:
> Hi George,
> 
> I have updated the Latest Xen nested status in the Xen wiki page, please have a look.
>
Hey Yang,

This is something really useful to have on the wiki, thanks for doing
it.

> Although it is hard to say nested is good supported or product quality, it is ready to let people to know nested basically is supported by Xen.
>
Right. With that in mind, I think this topic would be a great one for a
blog post on the Xen Project's blog! The content you have on the wiki is
mostly fine as the core content of the blog post too, we'd just need a
couple more "colloquial" glue paragraph here and there, both about
nested virt in general and about Xen supporting it, for instance...

> Especially, for Xen on Xen case, I didn't see any issue with it for more than half of year. Besides, I am always using nested Xen to debug Xen booting issue which doesn't need to reboot my real box. And it really helps me a lot.
>
...something like this line above... It's actually a quite good example
of what I meant above! :-)

So, how do you feel about this?

> So, if possible, I hope we can add nested support into Xen 4.4 release to let people know current status.
> 
Sorry for my ignorance on the subject, what is it that is missing for
making the above (and the content of the wiki) true for 4.4?

Anyway, I don't think that, whatever the answer is, it will be less
worth to have a blog post about nested virt... At most it will affect
when we want it. If it's going to be a 4.4 feature, I think the sooner
the better. If not, we can wait a little bit.

Let me know your thoughts on the idea.

Regards,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: Xen nested wiki

[Zhang, Yang Z]

Dario Faggioli wrote on 2014-02-13:
> [Adding the Xen publicity mailing list]
> 
> On gio, 2014-02-13 at 03:55 +0000, Zhang, Yang Z wrote:
>> Hi George,
>> 
>> I have updated the Latest Xen nested status in the Xen wiki page, 
>> please have a look.
>> 
> Hey Yang,
> 
> This is something really useful to have on the wiki, thanks for doing it.
> 
>> Although it is hard to say nested is good supported or product 
>> quality, it is ready to let people to know nested basically is supported by Xen.
>> 
> Right. With that in mind, I think this topic would be a great one for 
> a blog post on the Xen Project's blog! The content you have on the 
> wiki is mostly fine as the core content of the blog post too, we'd just need a couple more "colloquial"
> glue paragraph here and there, both about nested virt in general and 
> about Xen supporting it, for instance...
> 
>> Especially, for Xen on Xen case, I didn't see any issue with it for 
>> more than half
> of year. Besides, I am always using nested Xen to debug Xen booting 
> issue which doesn't need to reboot my real box. And it really helps me a lot.
>> 
> ...something like this line above... It's actually a quite good 
> example of what I meant above! :-)
> 
> So, how do you feel about this?
> 

Sure. If you can do it, that's great.

>> So, if possible, I hope we can add nested support into Xen 4.4 
>> release to let people know current status.
>> 
> Sorry for my ignorance on the subject, what is it that is missing for 
> making the above (and the content of the wiki) true for 4.4?
> 

Sorry. I didn't clarify it clearly. Most of the patches to run nested are already in Xen upstream. What I want is to add "nested is basically supported in Xen 4.4" in the Xen 4.4 release note to let people know it.

> Anyway, I don't think that, whatever the answer is, it will be less 
> worth to have a blog post about nested virt... At most it will affect 
> when we want it. If it's going to be a 4.4 feature, I think the sooner 
> the better. If not, we can wait a little bit.
> 
> Let me know your thoughts on the idea.
> 
> Regards,
> Dario
>


Best regards,
Yang

Re: Xen nested wiki

[George Dunlap]

On 02/14/2014 01:13 AM, Zhang, Yang Z wrote:
> Dario Faggioli wrote on 2014-02-13:
>> [Adding the Xen publicity mailing list]
>>
>> On gio, 2014-02-13 at 03:55 +0000, Zhang, Yang Z wrote:
>>> Hi George,
>>>
>>> I have updated the Latest Xen nested status in the Xen wiki page,
>>> please have a look.
>>>
>> Hey Yang,
>>
>> This is something really useful to have on the wiki, thanks for doing it.
>>
>>> Although it is hard to say nested is good supported or product
>>> quality, it is ready to let people to know nested basically is supported by Xen.
>>>
>> Right. With that in mind, I think this topic would be a great one for
>> a blog post on the Xen Project's blog! The content you have on the
>> wiki is mostly fine as the core content of the blog post too, we'd just need a couple more "colloquial"
>> glue paragraph here and there, both about nested virt in general and
>> about Xen supporting it, for instance...
>>
>>> Especially, for Xen on Xen case, I didn't see any issue with it for
>>> more than half
>> of year. Besides, I am always using nested Xen to debug Xen booting
>> issue which doesn't need to reboot my real box. And it really helps me a lot.
>> ...something like this line above... It's actually a quite good
>> example of what I meant above! :-)
>>
>> So, how do you feel about this?
>>
> Sure. If you can do it, that's great.
>
>>> So, if possible, I hope we can add nested support into Xen 4.4
>>> release to let people know current status.
>>>
>> Sorry for my ignorance on the subject, what is it that is missing for
>> making the above (and the content of the wiki) true for 4.4?
>>
> Sorry. I didn't clarify it clearly. Most of the patches to run nested are already in Xen upstream. What I want is to add "nested is basically supported in Xen 4.4" in the Xen 4.4 release note to let people know it.

I'm afraid "basically supported" will imply to people that they might 
consider shipping it on production systems.  But because of the issues 
with shadow-on-HAP, and the potential locking issues with the nested p2m 
table, both of which are in control of the guest admin rather than the 
host admin, I don't think that's a recommendation we can make at this time.

But I do think making some kind of announcement about common 
functionality being complete and ready to be tested would be a good 
idea.  When we come to make the release we can brainstorm on what 
wording to use.

Actually, I wonder whether advertising Win7's XP compatibility mode as a 
separate "tech preview" feature would make sense.  The people who use 
that feature are very likely very different than most other people who 
might think about using nested virtualization.

Also, re what's missing: We had a discussion a few weeks ago about what 
it might take to move nested virt out of "tech preview/experimental" 
mode.  I'll write those up and put them in my 4.4 planning e-mail so we 
can track the progress.

  -George

Re: Xen nested wiki

[Dario Faggioli]

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On ven, 2014-02-14 at 10:24 +0000, George Dunlap wrote:
> On 02/14/2014 01:13 AM, Zhang, Yang Z wrote:

> > Sorry. I didn't clarify it clearly. Most of the patches to run nested are already in Xen upstream. What I want is to add "nested is basically supported in Xen 4.4" in the Xen 4.4 release note to let people know it.
> 
> I'm afraid "basically supported" will imply to people that they might 
> consider shipping it on production systems.  But because of the issues 
> with shadow-on-HAP, and the potential locking issues with the nested p2m 
> table, both of which are in control of the guest admin rather than the 
> host admin, I don't think that's a recommendation we can make at this time.
> 
> But I do think making some kind of announcement about common 
> functionality being complete and ready to be tested would be a good 
> idea.  When we come to make the release we can brainstorm on what 
> wording to use.
> 
I agree. Let's not sell something not entirely ready, as that could
backfire, but we should at least hint that it's there and it's improved.

> Actually, I wonder whether advertising Win7's XP compatibility mode as a 
> separate "tech preview" feature would make sense.  The people who use 
> that feature are very likely very different than most other people who 
> might think about using nested virtualization.
> 
Completely agree again. And this is something that could be very well
described in a blog post on the subject (happening after the release), I
think. :-)

Regads,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: Xen nested wiki

[Zhang, Yang Z]

Dario Faggioli wrote on 2014-02-14:
> On ven, 2014-02-14 at 10:24 +0000, George Dunlap wrote:
>> On 02/14/2014 01:13 AM, Zhang, Yang Z wrote:
> 
>>> Sorry. I didn't clarify it clearly. Most of the patches to run nested are already
> in Xen upstream. What I want is to add "nested is basically supported in Xen
> 4.4" in the Xen 4.4 release note to let people know it.
>> 
>> I'm afraid "basically supported" will imply to people that they might
>> consider shipping it on production systems.  But because of the issues
>> with shadow-on-HAP, and the potential locking issues with the nested p2m
>> table, both of which are in control of the guest admin rather than the

Hi, George,

Can you elaborate the two issues? I am not in the background.

>> host admin, I don't think that's a recommendation we can make at this time.
>> 
>> But I do think making some kind of announcement about common
>> functionality being complete and ready to be tested would be a good
>> idea.  When we come to make the release we can brainstorm on what
>> wording to use.
>> 
> I agree. Let's not sell something not entirely ready, as that could
> backfire, but we should at least hint that it's there and it's improved.
> 

I agree too. A hint to say it is there should be ok to me.

>> Actually, I wonder whether advertising Win7's XP compatibility mode as a
>> separate "tech preview" feature would make sense.  The people who use
>> that feature are very likely very different than most other people who
>> might think about using nested virtualization.
>> 
> Completely agree again. And this is something that could be very well
> described in a blog post on the subject (happening after the release), I
> think. :-)
> 
> Regads,
> Dario
>


Best regards,
Yang

Re: Xen nested wiki

[Dario Faggioli]

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On ven, 2014-02-14 at 01:13 +0000, Zhang, Yang Z wrote:
> Dario Faggioli wrote on 2014-02-13:
> > ...something like this line above... It's actually a quite good 
> > example of what I meant above! :-)
> > 
> > So, how do you feel about this?
> > 
> 
> Sure. If you can do it, that's great.
>
Cool! So, first step for this is you go to blog.xen.org and register,
and then let me know your username, so that I can allow you to write
blog posts.

No need to rush, of course. Although, as per George summary, nested virt
won't be advertised as production ready for 4.4, I still think that it
may be worthwhile waiting after the release, as Sarah was suggesting.

Thanks and Regards,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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Re: Xen nested wiki

[Pasi Kärkkäinen]

On Thu, Feb 13, 2014 at 03:55:31AM +0000, Zhang, Yang Z wrote:
> Hi George,
> 

Hello,

> I have updated the Latest Xen nested status in the Xen wiki page, please have a look.
> Although it is hard to say nested is good supported or product quality, it is ready to let people to know nested basically is supported by Xen. Especially, for Xen on Xen case, I didn't see any issue with it for more than half of year. Besides, I am always using nested Xen to debug Xen booting issue which doesn't need to reboot my real box. And it really helps me a lot. So, if possible, I hope we can add nested support into Xen 4.4 release to let people know current status.
> 
> Xen nested wiki:
> http://wiki.xenproject.org/wiki/Xen_nested
>

Thanks a lot for writing that! Good stuff.

How about the bugfix patches mentioned on the wiki page:
http://www.gossamer-threads.com/lists/xen/devel/316994
http://www.gossamer-threads.com/lists/xen/devel/316993

It looks like the patch 2/2 needs some more work, is it likely to be fixed/merged before Xen 4.4 final? 
(is it suitable to be merged as a bugfix?)

Thanks,

-- Pasi

 
> best regards
> yang
> 

Re: Xen nested wiki

[Zhang, Yang Z]

Pasi Kärkkäinen wrote on 2014-02-13:
> On Thu, Feb 13, 2014 at 03:55:31AM +0000, Zhang, Yang Z wrote:
>> Hi George,
>> 
> 
> Hello,
> 
>> I have updated the Latest Xen nested status in the Xen wiki page,
>> please have a look. Although it is hard to say nested is good supported
>> or product quality, it is
> ready to let people to know nested basically is supported by Xen.
> Especially, for Xen on Xen case, I didn't see any issue with it for more than half of year.
> Besides, I am always using nested Xen to debug Xen booting issue which
> doesn't need to reboot my real box. And it really helps me a lot. So,
> if possible, I hope we can add nested support into Xen 4.4 release to
> let people know current status.
>> 
>> Xen nested wiki:
>> http://wiki.xenproject.org/wiki/Xen_nested
>> 
> 
> Thanks a lot for writing that! Good stuff.
> 
> How about the bugfix patches mentioned on the wiki page:
> http://www.gossamer-threads.com/lists/xen/devel/316994
> http://www.gossamer-threads.com/lists/xen/devel/316993
> 
> It looks like the patch 2/2 needs some more work, is it likely to be
> fixed/merged before Xen 4.4 final?

I will try my best to do it. But I am working on pushing GFX pass through to QEMU upstream to catch the Xen 4.4 now which having a higher priority to me and may occupy lots of my time. So I am not sure whether I have time to rework it and catch the Xen 4.4 release.
BTW: if you only want to boot Xen on Xen or KVM on Xen, those patches are not required. 

> (is it suitable to be merged as a bugfix?)

Yes. It is actually a bugfix.

> 
> Thanks,
> 
> -- Pasi
> 
> 
>> best regards
>> yang
>>


Best regards,
Yang