Re: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80

[Wanpeng Li]

Hi Paolo,
2016-06-21 18:24 GMT+08:00 Wanpeng Li <kernellwp@xxxxxxxxx>:
> 2016-06-21 18:10 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>:
>>
>>
>> On 21/06/2016 08:08, Wanpeng Li wrote:
>>> Cc KVM ML, Paolo, Radim,
>>>>> FYI, raw QEMU command line is:
>>>>>
>>>>>         qemu-system-x86_64 -enable-kvm -cpu SandyBridge -kernel /pkg/linux/x86_64-randconfig-w0-06180628/gcc-6/19fa5e73647fde1e6a7038a8f05cddf4c43f08d3/vmlinuz-4.7.0-rc3-00009-g19fa5e7 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-yocto-x86_64-32/bisect_boot-1-yocto-minimal-x86_64.cgz-x86_64-randconfig-w0-06180628-19fa5e73647fde1e6a7038a8f05cddf4c43f08d3-20160618-25535-h82bax-0.yaml~ ARCH=x86_64 kconfig=x86_64-randconfig-w0-06180628 branch=internal-eywa/master commit=19fa5e73647fde1e6a7038a8f05cddf4c43f08d3 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-w0-06180628/gcc-6/19fa5e73647fde1e6a7038a8f05cddf4c43f08d3/vmlinuz-4.7.0-rc3-00009-g19fa5e7 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-kbuild-yocto-x86_64/yocto-minimal-x86_64.cgz/x86_64-randconfig-w0-06180628/gcc-6/19fa5e73647fde1e6a7038a8f05cddf4c43f08d3/0 LKP_SERVER=inn earlyprintk=ttyS0,115200 systemd.log_level=err debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-kbuild-yocto-x86_64-32::dhcp drbd.minor_count=8'  -initrd /fs/sdh1/initrd-vm-kbuild-yocto-x86_64-32 -m 320 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdh1/disk0-vm-kbuild-yocto-x86_64-32,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-yocto-x86_64-32 -serial file:/dev/shm/kboot/serial-vm-kbuild-yocto-x86_64-32 -daemonize -display none -monitor null
>>>>>
>>>> This  problem was caused due to kvm does not support MSR_PLATFORM_INFO(0xce),
>>>> according to Wanpeng's feedback.
>>>>
>>>> Hi Wanpeng, is it possible for kvm to simulate this MSR, otherwise we
>>>> might have to use
>>>> rdmsr_safe instead.
>>>
>>> There is a thread discussed this before
>>> https://patchwork.kernel.org/patch/8833021/, MSR_PLATFORM_INFO can't
>>> be simple emulation.
>>>
>>> Ping Paolo, Radim. :)
>>
>> rdmsr_safe must be used instead.  I'll prepare a patch.
>
> Actually I have such a patch on hand under testing, I will send out soon. :)

I have a temporal patch as below, it seems that guest tsc(~300MHz) is
still not correct and guest kernel panic during boot w/ message
"MP-BIOS bug: 8254 timer not connect to IO-APIC, kernel-panic - not
syncing: IOAPIC + timer doesn't work" etc. Any proposal to improve my
patch is a great appreciated. :) The patch is against x86 branch on
Len Brown's tree. And try to fix this commit:
https://git.kernel.org/cgit/linux/kernel/git/lenb/linux.git/commit/?h=x86&id=fc141535ad8a67fd58623289c04e35465e2a07f2

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