Re: [Qemu-discuss] qemu 2.8.50 Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed

[Matwey V. Kornilov]

2017-02-03 1:00 GMT+03:00 Bandan Das <address@hidden>:
> "Matwey V. Kornilov" <address@hidden> writes:
>
>> 2017-02-03 0:13 GMT+03:00 Bandan Das <address@hidden>:
>>> "Matwey V. Kornilov" <address@hidden> writes:
>>>
>>>> 02.02.2017 22:36, Matwey V. Kornilov пишет:
>>>>>
>>>>> Hello,
>>>>>
>>>>> I see the following when try to run qemu from master as the following:
>>>>>
>>>>> # ./x86_64-softmmu/qemu-system-x86_64 --version
>>>>> QEMU emulator version 2.8.50 (v2.8.0-1006-g4e9f524)
>>>>> Copyright (c) 2003-2016 Fabrice Bellard and the QEMU Project developers
>>>>> # ./x86_64-softmmu/qemu-system-x86_64 -machine accel=kvm -nodefaults
>>>>> -no-reboot -nographic -cpu host -vga none  -kernel .build.kernel.kvm
>>>>> -initrd .build.initrd.kvm -append 'panic=1 no-kvmclock console=ttyS0
>>>>> loglevel=7' -m 1024 -serial stdio
>>>>> qemu-system-x86_64: /home/matwey/lab/qemu/target/i386/kvm.c:1849:
>>>>> kvm_put_msrs: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed.
>>>
>>> I think this means that KVM gave you a list of msrs but
>>> when you tried to set them, it could not set all of them and hence, the
>>> assert triggers.
>>>
>>> Are you using a modified kernel ? There could be something useful in the 
>>> host
>>> dmesg as well.
>>>
>>
>> I use vanilla 4.1.36
>>
>> Nothing relevant to kvm in dmesg except to
>>
>> [    5.265836] kvm: VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL does not work
>> properly. Using workaround
>
> Can you try using -cpu host,-pmu ? Or do you need vPMU for something ?

Hello,
-cpu host,-pmu helps. Unfortunately, I need '-cpu host'

>
>> [   43.574791] kvm [1249]: vcpu0 unhandled wrmsr: 0x38d data 0
>> [   43.580879] kvm [1249]: vcpu0 unhandled wrmsr: 0x38d data 0
>> [   43.706797] kvm [1249]: vcpu0 unhandled rdmsr: 0x38d
>>
>>
>>> Bandan
>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> Hello, I've bisected the first bad commit:
>>>>
>>>>
>>>> 48e1a45c3166d659f781171a47dabf4a187ed7a5 is the first bad commit
>>>> commit 48e1a45c3166d659f781171a47dabf4a187ed7a5
>>>> Author: Paolo Bonzini <address@hidden>
>>>> Date:   Wed Mar 30 22:55:29 2016 +0200
>>>>
>>>>     target-i386: assert that KVM_GET/SET_MSRS can set all requested MSRs
>>>>
>>>>     This would have caught the bug in the previous patch.
>>>>
>>>>     Signed-off-by: Paolo Bonzini <address@hidden>
>>>>
>>>> :040000 040000 5626b58f0d79261bbe8a4fb52bd2cc19c2aa86ad
>>>> d7580353932acab9de5c3d024b3f1215eb5659dc M      target-i386



-- 
With best regards,
Matwey V. Kornilov
http://blog.matwey.name
xmpp://address@hidden