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Re: [Qemu-devel] [Bug 1661386] Re: Assertion `ret == cpu->kvm_msr_buf->n
From: |
Matwey V. Kornilov |
Subject: |
Re: [Qemu-devel] [Bug 1661386] Re: Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed |
Date: |
Sun, 23 Jul 2017 10:24:36 -0000 |
2017-07-23 12:54 GMT+03:00 Matwey V. Kornilov <address@hidden>:
> 2017-02-08 11:49 GMT+03:00 Paolo Bonzini <address@hidden>:
>>> Does qemu follow recommendations from section 4.3?
>>
>> All that QEMU does is initialize MSR values and QEMU is talking to KVM,
>> not to the processor; KVM in turn talks to the host kernel's perf
>> subsystem.
>>
>> It's the host kernel's perf subsystem that needs to follow Intel's
>> recommendation. In particular, QEMU is setting CPUID to the values
>> retrieved by
>>
>> perf_get_x86_pmu_capability(&cap);
>
> I can not find this function mentioned in qemu master sources.
>
Ok, I found this place in kvm kernel module. But it doesn't do what
you expect it to do. It just reassembles 0xA EAX from previously
parsed data.
IA32_MISC_ENABLE is not accessed anywhere here.
> The only thing I see is that has_msr_architectural_pmu is set to be
> true in kvm_arch_init_vcpu() if 0xA EAX has non-zero version. This is
> not enough according to the Intel specs.
>
>>
>> so perhaps it's perf_get_x86_pmu_capability that misreads the
>> performance monitoring capabilities provided by ESX. Please attach
>> dmesg logs from starting the host with loglevel=9, as well as "x86info
>> -a" output from the host, to see if perf misses some problematic
>> CPUID/MSR combination.
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1661386
>>
>> Title:
>> Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed
>>
>> Status in QEMU:
>> New
>>
>> Bug description:
>> 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.
>>
>> First broken commit has been bisected:
>>
>> 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>
>>
>> My cpuinfo is the following:
>>
>> processor : 0
>> vendor_id : GenuineIntel
>> cpu family : 6
>> model : 44
>> model name : Intel(R) Xeon(R) CPU X5675 @ 3.07GHz
>> stepping : 2
>> microcode : 0x14
>> cpu MHz : 3066.775
>> cache size : 12288 KB
>> physical id : 0
>> siblings : 2
>> core id : 0
>> cpu cores : 2
>> apicid : 0
>> initial apicid : 0
>> fpu : yes
>> fpu_exception : yes
>> cpuid level : 11
>> wp : yes
>> flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
>> cmov pat pse36 clflush dts mmx fxsr sse sse2 ss ht syscall nx rdtscp lm
>> constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc
>> aperfmperf pni pclmulqdq vmx ssse3 cx16 sse4_1 sse4_2 popcnt aes hypervisor
>> lahf_lm ida arat epb dtherm tpr_shadow vnmi ept vpid
>> bugs :
>> bogomips : 6133.55
>> clflush size : 64
>> cache_alignment : 64
>> address sizes : 40 bits physical, 48 bits virtual
>> power management:
>>
>> To manage notifications about this bug go to:
>> https://bugs.launchpad.net/qemu/+bug/1661386/+subscriptions
>
>
>
> --
> With best regards,
> Matwey V. Kornilov
--
With best regards,
Matwey V. Kornilov
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1661386
Title:
Assertion `ret == cpu->kvm_msr_buf->nmsrs' failed
Status in QEMU:
New
Bug description:
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.
First broken commit has been bisected:
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>
My cpuinfo is the following:
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 44
model name : Intel(R) Xeon(R) CPU X5675 @ 3.07GHz
stepping : 2
microcode : 0x14
cpu MHz : 3066.775
cache size : 12288 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
cmov pat pse36 clflush dts mmx fxsr sse sse2 ss ht syscall nx rdtscp lm
constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc
aperfmperf pni pclmulqdq vmx ssse3 cx16 sse4_1 sse4_2 popcnt aes hypervisor
lahf_lm ida arat epb dtherm tpr_shadow vnmi ept vpid
bugs :
bogomips : 6133.55
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1661386/+subscriptions