Re: Unable to boot guest on kernel 2.6.29.1 with kvm-84 or kvm-85

Kenni Lund
2009-05-03T11:49:49Z

>Avi Kivity wrote:
>> Kenni Lund wrote:
>>> Avi Kivity avi@redhat.com wrote:
>>>
>>>> Kenni Lund wrote:
>>>>
>>>>> Ok, but as I write in my message, I'm using the
>>>>>
>>>> KVM modules from the latest> upstream kernel, not the kvm-85
>>>> modules.>
>>>>
>>>>> According to the KVM download page,
>>>>> http://www.linux-kvm.org/page/Downloads,> any kernel above 2.6.25
>>>>> should work with the
>>>>>
>>>> latest KVM userspace. This has> been true until now in my case, but
>>>> it breaks
>>>> with 2.6.29.1 and that's the reason> why I'm posting this bug report.
>>>>
>>>>>
>>>> Can you try a bisect?
>>>>
>>>
>>> Yes, sorry for the late reply. I did the bisect as requested and it
>>> returned the following results:
>>>
>>> # bad: [8d7bff2d72660d9d60aa371ae3d1356bbf329a09] Linux 2.6.29.1
>>> # good: [4a6908a3a050aacc9c3a2f36b276b46c0629ad91] Linux 2.6.28 git
>>> bisect start 'v2.6.29.1' 'v2.6.28' '--' 'arch/x86/kvm' 'virt/kvm'
>>> # good: [b82091824ee4970adf92d5cd6d57b12273171625] KVM: Prevent trace
>>> call into unloaded module text
>>> git bisect good
>>> b82091824ee4970adf92d5cd6d57b12273171625
>>> # good: [7f59f492da722eb3551bbe1f8f4450a21896f05d] KVM: use
>>> cpumask_var_t for cpus_hardware_enabled git bisect good
>>> 7f59f492da722eb3551bbe1f8f4450a21896f05d
>>> # good: [19de40a8472fa64693eab844911eec277d489f6c] KVM: change KVM to
>>> use IOMMU API git bisect good
>>> 19de40a8472fa64693eab844911eec277d489f6c
>>> # good: [2aaf69dcee864f4fb6402638dd2f263324ac839f] KVM: MMU: Map
>>> device MMIO as UC in EPT
>>> git bisect good 2aaf69dcee864f4fb6402638dd2f263324ac839f
>>> # good: [682edb4c01e690c7c7cd772dbd6f4e0fd74dc572] KVM: Fix assigned
>>> devices circular locking dependency
>>> git bisect good 682edb4c01e690c7c7cd772dbd6f4e0fd74dc572
>>> # bad: [f438349efb8247cd0c1d453a4131b1f801bf5691] KVM: VMX: Don't
>>> allow uninhibited access to EFER on i386
>>> git bisect bad f438349efb8247cd0c1d453a4131b1f801bf5691
>>> # good: [516a1a7e9dc80358030fe01aabb3bedf882db9e2] KVM: VMX: Flush
>>> volatile msrs before emulating rdmsr
>>> git bisect good 516a1a7e9dc80358030fe01aabb3bedf882db9e2
>>>
>>> ----------------
>>> And the final output:
>>>
>>> f438349efb8247cd0c1d453a4131b1f801bf5691 is first bad commit
>>> commit f438349efb8247cd0c1d453a4131b1f801bf5691
>>> Author: Avi Kivity Date: Thu Mar 26 23:05:03 2009 +0000
>>>
>>> KVM: VMX: Don't allow uninhibited access to EFER on i386
>>>
>>> upstream commit: 16175a796d061833aacfbd9672235f2d2725df65
>>>
>>> vmx_set_msr() does not allow i386 guests to touch EFER, but they
>>> can still
>>> do so through the default: label in the switch. If they set
>>> EFER_LME, they
>>> can oops the host.
>>>
>>> Fix by having EFER access through the normal channel (which will
>>> check for
>>> EFER_LME) even on i386.
>>>
>>> Reported-and-tested-by: Benjamin Gilbert Cc: stable@kernel.org
>>> Signed-off-by: Avi Kivity Signed-off-by: Chris Wright
>>> :040000 040000 cf7848d35c136beee6665e67839080d450977af0
>>> 0a39980481dd346306b2ac54dbe916741515f1f1 M arch
>>>
>>> ----------------
>>>
>>> FYI, I also tested 2.6.29.2 and the issue still exists.
>>>
>>> Do you need more information?
>>>
>>>
>>
>> Please try the attached patch.
>>
>
>It won't help - I reproduced the issue. Instead, try passing the
>parameter '-cpu qemu32' (or '-cpu qemu64,-nx').

Adding the parameter '-cpu qemu32' (32bit host + 32 bit guest) makes the WinXP guest boot.
...but is this parameter equal to '-no-kvm'? Eg. with emulated CPU?

Best Regards
Kenni Lund