unexpected exit_ini_info when nesting svm

unexpected exit_ini_info when nesting svm

[Olivier Berghmans]

Hi all,

I tried nesting kvm in kvm on an AMD processor with support for svm
and npt (the dmesg told me both were in use). I managed to install the
nested kvm and when starting the L2 guest in order to install an
operating system, I got following messages in the L1 guest:

[ 2016.712047] handle_exit: unexpected exit_ini_info 0x80000008 exit_code 0x60
[ 2031.432032] handle_exit: unexpected exit_ini_info 0x80000008 exit_code 0x60
[ 2034.468058] handle_exit: unexpected exit_ini_info 0x80000008 exit_code 0x60

The guest did not boot at all so I tried to start a pre-installed
image. When booting the pre-installed image it hangs at:

Boot from (hd0,0) ext3
Starting up ...
_

And in the L1 guest I received similar messages (except that it ends
with 76 now):

[ 154.015985] handle_exit: unexpected exit_ini_info 0x80000076 exit_code 0x60
[ 154.022781] handle_exit: unexpected exit_ini_info 0x80000076 exit_code 0x60
...
[ 154.276078] handle_exit: unexpected exit_ini_info 0x80000076 exit_code 0x60

After searching for these messages I saw that the messages come from
the file drivers/kvm/svm.c . What may cause this problem? Is it a part
of the nested svm that still needs to be implemented or something with
performance?

Thanks in advance,
Olivier

Re: unexpected exit_ini_info when nesting svm

[Joerg Roedel]

Hello Oliver,

On Thu, Mar 18, 2010 at 08:43:53PM +0100, Olivier Berghmans wrote:
> I tried nesting kvm in kvm on an AMD processor with support for svm
> and npt (the dmesg told me both were in use). I managed to install the
> nested kvm and when starting the L2 guest in order to install an
> operating system, I got following messages in the L1 guest:
> 
> [ 2016.712047] handle_exit: unexpected exit_ini_info 0x80000008 exit_code 0x60
> [ 2031.432032] handle_exit: unexpected exit_ini_info 0x80000008 exit_code 0x60
> [ 2034.468058] handle_exit: unexpected exit_ini_info 0x80000008 exit_code 0x60

These messages result from a difference between a real hardware svm and
the emulated svm from kvm. Hardware SVM always injects an exception
first before it does an #vmexit(0x60) while the svm emulation does
immediatlt #vmexit again. I have a patch to fix this but it needs more
testing.

The patch implements detection of the above situation and sends an
self-ipi in this case.

	Joerg