[Bug 75981] New: [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[Bug 75981] New: [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

            Bug ID: 75981
           Summary: [Nested kvm on kvm]L2 guest reboot continuously when
                    create a rhel6u5(64bit) as L2 guest.
           Product: Virtualization
           Version: unspecified
    Kernel Version: 3.15.0-rc1
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: kvm
          Assignee: virtualization_kvm@kernel-bugs.osdl.org
          Reporter: chao.zhou@intel.com
        Regression: No

Environment:
------------
Host OS (ia32/ia32e/IA64):ia32e
Guest OS (ia32/ia32e/IA64):ia32e
Guest OS Type (Linux/Windows):Linux
kvm.git Commit:198c74f43f0f5473f99967aead30ddc622804bc1
qemu.git Commit:411f491e0af173cf8f39347574941bd26fbae381
Host Kernel Version:3.15.0-rc1
Hardware:Romley_EP


Bug detailed description:
--------------------------
when create L1 guest with "-cpu host" , then create a 64bit rhel6u5 guest as L2
guest, the L2 guest reboot continuously.

note:
1. create a 64bit RHEL6u4 as L2 guest, the guest reboot continuously.
2. when creat a 32bit rhel6u5 guest as L2 guest, the L2 guest works fine
3. this should be a kernel bug:
kvm      +  qemu     = result
198c74f4 + 411f491e  = bad
0f689a33 + 411f491e  = good


Reproduce steps:
----------------
1. create L1 guest:
qemu-system-x86_64 -enable-kvm -m 8G -smp 4 -net nic,macaddr=00:12:41:51:14:16
-net tap,script=/etc/kvm/qemu-ifup ia32e_nested-kvm.img -cpu host,level=9
2. create L2 guest
qemu-system-x86_64 -enable-kvm -m 1024 -smp 2 -net none ia32e_rhel6u4.img


Current result:
----------------
64bit rhel6u5 as L2 guest reboot continuously

Expected result:
----------------
64bit rhel6u5 as L2 guest works fine

Basic root-causing log:
----------------------

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

--- Comment #1 from Zhou, Chao <chao.zhou@intel.com> ---
the first bad commit is:
commit 346874c9507a2582d0c00021f848de6e115f276c
Author: Nadav Amit <namit@cs.technion.ac.il>
Date:   Fri Apr 18 03:35:09 2014 +0300

    KVM: x86: Fix CR3 reserved bits

    According to Intel specifications, PAE and non-PAE does not have any
reserved
    bits.  In long-mode, regardless to PCIDE, only the high bits (above the
    physical address) are reserved.

    Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
    Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

Jan Kiszka <jan.kiszka@web.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jan.kiszka@web.de

--- Comment #2 from Jan Kiszka <jan.kiszka@web.de> ---
Might be fixed by "KVM: x86: Fix CR3 reserved bits check in long mode"
(http://thread.gmane.org/gmane.linux.kernel/1700662).

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

Paolo Bonzini <bonzini@gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini@gnu.org

--- Comment #3 from Paolo Bonzini <bonzini@gnu.org> ---
I applied that patch to kvm/next and kvm/queue, however I haven't yet tested
nested virt so I'm not yet closing.

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

--- Comment #4 from Zhou, Chao <chao.zhou@intel.com> ---
kvm.git + qemu.git: d9f89b88_e5bfd640
host kernel:3.15.0_rc1
test on Romley_EP, create a 64bit rhel6u5 guest as L2 guest, the L2 guest boots
up fine.

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

--- Comment #5 from Zhou, Chao <chao.zhou@intel.com> ---
this commit fixed the bug:
commit d9f89b88f5102ce235b75a5907838e3c7ed84b97
Author: Jan Kiszka <jan.kiszka@siemens.com>
Date:   Sat May 10 09:24:34 2014 +0200

    KVM: x86: Fix CR3 reserved bits check in long mode

    Regression of 346874c9: PAE is set in long mode, but that does not mean
    we have valid PDPTRs.

    Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

Zhou, Chao <chao.zhou@intel.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |CODE_FIX

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[Bug 75981] [Nested kvm on kvm]L2 guest reboot continuously when create a rhel6u5(64bit) as L2 guest.

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=75981

Zhou, Chao <chao.zhou@intel.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |VERIFIED

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