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Re: [Xen-devel] Re: [Xen-users] Nested Virtualisation question

To: Keir Fraser <keir@xxxxxxx>
Subject: Re: [Xen-devel] Re: [Xen-users] Nested Virtualisation question
From: Jeroen Groenewegen van der Weyden <groen692@xxxxxxxxx>
Date: Sat, 09 Apr 2011 15:32:56 +0200
Cc: "Christoph.Egger@xxxxxxx" <Christoph.Egger@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Dong, Eddie" <eddie.dong@xxxxxxxxx>, Tim Deegan <Tim.Deegan@xxxxxxxxxx>
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I'm now testing on a intel q9450, which does not seem to have this. I will move my testing to a intel e5645 which seems to have this capability.

Question then is, when will the intel support be implemented? is there commitment from some developer? is there a roadmap planned. in short what is the story here.


Op 9-4-2011 13:15, Keir Fraser schreef:
On 09/04/2011 11:18, "Jeroen Groenewegen van der Weyden"
<groen692@xxxxxxxxx>  wrote:

The HAP is default set to one, I check this also with a dry run.
Please confirm all this support just amd, because I only have Intel
Well, quite apart from being AMD only right now (Intel patches have been
posted in the past, but they're not in tree yet, and I very much doubt old
patches would directly apply to our current development tree), I'm also
pretty sure that your machine doesn't support Intel EPT -- if the processor
can't support HAP then we silently discard that configuration request when
creating a domain. That's why you get error 22 (EINVAL). But even if you did
have Intel EPT, because Intel's nested virt patches aren't in tree yet you'd
just get error 95 (EOPNOTSUPP) instead!

By the way you can tell if your system supports EPT by grepping in 'xm
dmesg' output (i.e., Xen's boot log) for a line stating "Extended Page
Tables (EPT)".

  -- Keir


Op 9-4-2011 8:22, Keir Fraser schreef:
On 09/04/2011 06:07, "Jeroen Groenewegen van der Weyden"
<groen692@xxxxxxxxx>   wrote:

The result with c/s23197

Regular domain now start, en stop normaly, (xl seems to have a problem
though, after domain closes a domain null remains in de xl list/ xmdoe
not have this.)
for nestedVM I added the "nestedhvm=1" in the config file of the domain.
but the domain does not start because of "invalid argument"
NestedHVM currently requires you to be using an AMD processor with hardware
nested paging (known as HAP by Xen). Most likely you need to add hap=1 to
your config file (and hope your processor supports it).

   -- Keir

+++++++++ beging console
hydra:/etc/xen/vm # xm create groscNestedVM
Using config file "./groscNestedVM".
Error: (22, 'Invalid argument')
+++++++++ end console

+++++++++ begin xend.log
hydra:/etc/xen/vm # tail /var/log/xen/xend.log
       dominfo = XendDomainInfo.create(config)
     File "/usr/lib64/python2.7/site-packages/xen/xend/XendDomainInfo.py",
line 106, in create
     File "/usr/lib64/python2.7/site-packages/xen/xend/XendDomainInfo.py",
line 473, in start
       XendTask.log_progress(0, 30, self._constructDomain)
     File "/usr/lib64/python2.7/site-packages/xen/xend/XendTask.py", line
209, in log_progress
       retval = func(*args, **kwds)
     File "/usr/lib64/python2.7/site-packages/xen/xend/XendDomainInfo.py",
line 2598, in _constructDomain
       xc.hvm_set_param(self.domid, HVM_PARAM_NESTEDHVM, long(nestedhvm))
Error: (22, 'Invalid argument')
+++++++++++ end xend.log

Op 7-4-2011 12:29, Tim Deegan schreef:
At 08:14 +0100 on 07 Apr (1302164093), Keir Fraser wrote:
On 07/04/2011 08:09, "Keir Fraser"<keir.xen@xxxxxxxxx>    wrote:
Probably the same as this, happening often in the automated tests:
Likely reason: nestedhvm_vcpu_initialise() being called unconditionally in
hvm_vcpu_initialise() even though nestedhvm has not been configured for
domain. This then fails because there is no nestedhvm handler for Intel
This bug should be fixed by 23175:e5a750d1bf9b, arriving at a staging
tree near you at any moment.

And beyond that it's most likely an issue of a broken failure path, or a
problem in the HAP code with cleaning up a half-created guest.
This one I'll look into now.


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