Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1427329 > unrolled thread

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

Started byYu Chen <yu.chen.surf@gmail.com>
First post2016-06-21 07:50 +0200
Last post2016-06-22 01:40 +0200
Articles 6 — 3 participants

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80 Yu Chen <yu.chen.surf@gmail.com> - 2016-06-21 07:50 +0200
    Re: 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 <kernellwp@gmail.com> - 2016-06-21 08:10 +0200
      Re: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80 Paolo Bonzini <pbonzini@redhat.com> - 2016-06-21 12:20 +0200
        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 <kernellwp@gmail.com> - 2016-06-21 12:40 +0200
          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 <kernellwp@gmail.com> - 2016-06-21 16:00 +0200
            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 <kernellwp@gmail.com> - 2016-06-22 01:40 +0200

#1427329 — Re: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80

FromYu Chen <yu.chen.surf@gmail.com>
Date2016-06-21 07:50 +0200
SubjectRe: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80
Message-ID<rMmJs-1D1-11@gated-at.bofh.it>
Hi,

On Mon, Jun 20, 2016 at 3:31 PM, kernel test robot
<xiaolong.ye@intel.com> wrote:
>
> FYI, we noticed the following commit:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux.git x86
> commit 19fa5e73647fde1e6a7038a8f05cddf4c43f08d3 ("x86 tsc: enumerate SKL cpu_khz and tsc_khz via CPUID")
>
>
> on test machine: vm-kbuild-yocto-x86_64: 1 threads qemu-system-x86_64 -enable-kvm -cpu SandyBridge with 320M memory
>
> caused below changes:
>
>
> +------------------------------------------------------------------+------------+------------+
> |                                                                  | cc50dc7f73 | 19fa5e7364 |
> +------------------------------------------------------------------+------------+------------+
> | boot_successes                                                   | 0          | 0          |
> | boot_failures                                                    | 10         | 12         |
> | invoked_oom-killer:gfp_mask=0x                                   | 10         | 10         |
> | Mem-Info                                                         | 10         | 10         |
> | Kernel_panic-not_syncing:Out_of_memory_and_no_killable_processes | 10         | 10         |
> | backtrace:btrfs_test_extent_io                                   | 10         | 10         |
> | backtrace:init_btrfs_fs                                          | 10         | 10         |
> | backtrace:kernel_init_freeable                                   | 10         | 10         |
> | WARNING:at_arch/x86/mm/extable.c:#ex_handler_rdmsr_unsafe        | 0          | 10         |
> | backtrace:native_calibrate_cpu                                   | 0          | 10         |
> | backtrace:tsc_init                                               | 0          | 10         |
> | backtrace:x86_late_time_init                                     | 0          | 10         |
> +------------------------------------------------------------------+------------+------------+
>
>
>
> [    0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604467 ns
> [    0.000000] hpet clockevent registered
> [    0.000000] ------------[ cut here ]------------
> [    0.000000] WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80
> [    0.000000] unchecked MSR access error: RDMSR from 0xce
> [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3-00009-g19fa5e7 #1
> [    0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
> [    0.000000]  0000000000000000 ffffffff83203c38 ffffffff816da89d ffffffff83203c88
> [    0.000000]  0000000000000000 ffffffff82e71808 ffffffff8104e8c2 ffffffff83203c78
> [    0.000000]  ffffffff810b796b 000000328453b4a0 ffffffff82e71808 0000000000000032
> [    0.000000] Call Trace:
> [    0.000000]  [<ffffffff816da89d>] dump_stack+0x83/0xb6
> [    0.000000]  [<ffffffff8104e8c2>] ? ex_handler_rdmsr_unsafe+0x72/0x80
> [    0.000000]  [<ffffffff810b796b>] __warn+0x10b/0x130
> [    0.000000]  [<ffffffff810b79f3>] warn_slowpath_fmt+0x63/0x70
> [    0.000000]  [<ffffffff8104e8c2>] ex_handler_rdmsr_unsafe+0x72/0x80
> [    0.000000]  [<ffffffff8104ea26>] fixup_exception+0x46/0x60
> [    0.000000]  [<ffffffff81020fdb>] do_general_protection+0x7b/0x150
> [    0.000000]  [<ffffffff828101d8>] general_protection+0x28/0x30
> [    0.000000]  [<ffffffff810496d6>] ? native_read_msr+0x6/0x20
> [    0.000000]  [<ffffffff810281e1>] cpu_khz_from_msr+0xf1/0x150
> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
> [    0.000000]  [<ffffffff81027935>] native_calibrate_cpu+0x85/0x5b0
> [    0.000000]  [<ffffffff81049826>] ? native_restore_fl+0x6/0x10
> [    0.000000]  [<ffffffff81112556>] ? __setup_irq+0x196/0x750
> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
> [    0.000000]  [<ffffffff8341ec3f>] tsc_init+0x42/0x3c3
> [    0.000000]  [<ffffffff81112c5f>] ? setup_irq+0x6f/0xc0
> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
> [    0.000000]  [<ffffffff8341b17a>] x86_late_time_init+0xf/0x11
> [    0.000000]  [<ffffffff8341b17a>] ? x86_late_time_init+0xf/0x11
> [    0.000000]  [<ffffffff83414173>] start_kernel+0x3f3/0x4b1
> [    0.000000]  [<ffffffff83413120>] ? early_idt_handler_array+0x120/0x120
> [    0.000000]  [<ffffffff8341329e>] x86_64_start_reservations+0x2f/0x31
> [    0.000000]  [<ffffffff83413386>] x86_64_start_kernel+0xe6/0xf3
> [    0.000000] ---[ end trace 7c0d92684f22f4ac ]---
> [    0.000000] tsc: Fast TSC calibration using PIT
>
>
> 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.

-- 
thanks,
Yu

[toc] | [next] | [standalone]

#1427337

FromWanpeng Li <kernellwp@gmail.com>
Date2016-06-21 08:10 +0200
Message-ID<rMn2N-20i-9@gated-at.bofh.it>
In reply to#1427329
Cc KVM ML, Paolo, Radim,
> Hi,
>
> On Mon, Jun 20, 2016 at 3:31 PM, kernel test robot
> <xiaolong.ye@intel.com> wrote:
>>
>> FYI, we noticed the following commit:
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux.git x86
>> commit 19fa5e73647fde1e6a7038a8f05cddf4c43f08d3 ("x86 tsc: enumerate SKL cpu_khz and tsc_khz via CPUID")
>>
>>
>> on test machine: vm-kbuild-yocto-x86_64: 1 threads qemu-system-x86_64 -enable-kvm -cpu SandyBridge with 320M memory
>>
>> caused below changes:
>>
>>
>> +------------------------------------------------------------------+------------+------------+
>> |                                                                  | cc50dc7f73 | 19fa5e7364 |
>> +------------------------------------------------------------------+------------+------------+
>> | boot_successes                                                   | 0          | 0          |
>> | boot_failures                                                    | 10         | 12         |
>> | invoked_oom-killer:gfp_mask=0x                                   | 10         | 10         |
>> | Mem-Info                                                         | 10         | 10         |
>> | Kernel_panic-not_syncing:Out_of_memory_and_no_killable_processes | 10         | 10         |
>> | backtrace:btrfs_test_extent_io                                   | 10         | 10         |
>> | backtrace:init_btrfs_fs                                          | 10         | 10         |
>> | backtrace:kernel_init_freeable                                   | 10         | 10         |
>> | WARNING:at_arch/x86/mm/extable.c:#ex_handler_rdmsr_unsafe        | 0          | 10         |
>> | backtrace:native_calibrate_cpu                                   | 0          | 10         |
>> | backtrace:tsc_init                                               | 0          | 10         |
>> | backtrace:x86_late_time_init                                     | 0          | 10         |
>> +------------------------------------------------------------------+------------+------------+
>>
>>
>>
>> [    0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604467 ns
>> [    0.000000] hpet clockevent registered
>> [    0.000000] ------------[ cut here ]------------
>> [    0.000000] WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80
>> [    0.000000] unchecked MSR access error: RDMSR from 0xce
>> [    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3-00009-g19fa5e7 #1
>> [    0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
>> [    0.000000]  0000000000000000 ffffffff83203c38 ffffffff816da89d ffffffff83203c88
>> [    0.000000]  0000000000000000 ffffffff82e71808 ffffffff8104e8c2 ffffffff83203c78
>> [    0.000000]  ffffffff810b796b 000000328453b4a0 ffffffff82e71808 0000000000000032
>> [    0.000000] Call Trace:
>> [    0.000000]  [<ffffffff816da89d>] dump_stack+0x83/0xb6
>> [    0.000000]  [<ffffffff8104e8c2>] ? ex_handler_rdmsr_unsafe+0x72/0x80
>> [    0.000000]  [<ffffffff810b796b>] __warn+0x10b/0x130
>> [    0.000000]  [<ffffffff810b79f3>] warn_slowpath_fmt+0x63/0x70
>> [    0.000000]  [<ffffffff8104e8c2>] ex_handler_rdmsr_unsafe+0x72/0x80
>> [    0.000000]  [<ffffffff8104ea26>] fixup_exception+0x46/0x60
>> [    0.000000]  [<ffffffff81020fdb>] do_general_protection+0x7b/0x150
>> [    0.000000]  [<ffffffff828101d8>] general_protection+0x28/0x30
>> [    0.000000]  [<ffffffff810496d6>] ? native_read_msr+0x6/0x20
>> [    0.000000]  [<ffffffff810281e1>] cpu_khz_from_msr+0xf1/0x150
>> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
>> [    0.000000]  [<ffffffff81027935>] native_calibrate_cpu+0x85/0x5b0
>> [    0.000000]  [<ffffffff81049826>] ? native_restore_fl+0x6/0x10
>> [    0.000000]  [<ffffffff81112556>] ? __setup_irq+0x196/0x750
>> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
>> [    0.000000]  [<ffffffff8341ec3f>] tsc_init+0x42/0x3c3
>> [    0.000000]  [<ffffffff81112c5f>] ? setup_irq+0x6f/0xc0
>> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
>> [    0.000000]  [<ffffffff8341b16b>] ? trap_init+0x22e/0x22e
>> [    0.000000]  [<ffffffff8341b17a>] x86_late_time_init+0xf/0x11
>> [    0.000000]  [<ffffffff8341b17a>] ? x86_late_time_init+0xf/0x11
>> [    0.000000]  [<ffffffff83414173>] start_kernel+0x3f3/0x4b1
>> [    0.000000]  [<ffffffff83413120>] ? early_idt_handler_array+0x120/0x120
>> [    0.000000]  [<ffffffff8341329e>] x86_64_start_reservations+0x2f/0x31
>> [    0.000000]  [<ffffffff83413386>] x86_64_start_kernel+0xe6/0xf3
>> [    0.000000] ---[ end trace 7c0d92684f22f4ac ]---
>> [    0.000000] tsc: Fast TSC calibration using PIT
>>
>>
>> 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. :)

Regards,
Wanpeng Li

[toc] | [prev] | [next] | [standalone]

#1427564

FromPaolo Bonzini <pbonzini@redhat.com>
Date2016-06-21 12:20 +0200
Message-ID<rMqWJ-4rb-11@gated-at.bofh.it>
In reply to#1427337

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.

Paolo

[toc] | [prev] | [next] | [standalone]

#1427583

FromWanpeng Li <kernellwp@gmail.com>
Date2016-06-21 12:40 +0200
Message-ID<rMrg6-4Cx-33@gated-at.bofh.it>
In reply to#1427564
2016-06-21 18:10 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
>
>
> 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. :)

Regards,
Wanpeng Li

[toc] | [prev] | [next] | [standalone]

#1427774

FromWanpeng Li <kernellwp@gmail.com>
Date2016-06-21 16:00 +0200
Message-ID<rMunD-6zQ-1@gated-at.bofh.it>
In reply to#1427583
Hi Paolo,
2016-06-21 18:24 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
> 2016-06-21 18:10 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
>>
>>
>> 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

--------------------

From 8033ae4c7e44d6bfe26642b151de03c613125066 Mon Sep 17 00:00:00 2001
From: Wanpeng Li <wanpeng.li@hotmail.com>
Date: Tue, 21 Jun 2016 19:41:12 +0800
Subject: [PATCH] x86: fix rdmsr MSR_PLATFORM_INFO unsafe warning in kvm guest

From: Wanpeng Li <wanpeng.li@hotmail.com>

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50
ex_handler_rdmsr_unsafe+0x6a/0x70
unchecked MSR access error: RDMSR from 0xce
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 0000000000000000 ffffffff81c03ce0 ffffffff813b3eae ffffffff81c03d30
 0000000000000000 ffffffff81c03d20 ffffffff81067181 0000003200000001
 ffffffff81c03df8 ffffffff8179676c 0000000000000000 ffffffff81fcd2c0
Call Trace:
 dump_stack+0x67/0x99
 __warn+0xd1/0xf0
 warn_slowpath_fmt+0x4f/0x60
 ex_handler_rdmsr_unsafe+0x6a/0x70
 fixup_exception+0x39/0x50
 do_general_protection+0x93/0x1b0
 general_protection+0x22/0x30
 ? cpu_khz_from_msr+0xd8/0x1c0
 native_calibrate_cpu+0x30/0x5b0
 tsc_init+0x2b/0x297
 x86_late_time_init+0xf/0x11
 start_kernel+0x398/0x451
 ? set_init_arg+0x55/0x55
 x86_64_start_reservations+0x2f/0x31
 x86_64_start_kernel+0xea/0xed

After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core
Architecture"),
rdmsr MSR_PLATFORM_INFO is used to get maximum non-turbo ratio for
recent Intel Core
Architecture which results in kvm guest rdmsr unsafe warning.

As Radim pointed out before:

| MSR_PLATFORM_INFO: Intel changes it from family to family and there is
| no obvious overlap or default.  If we picked 0 (any other fixed value),
| then the guest would have to know that 0 doesn't mean that
| MSR_PLATFORM_INFO returned 0, but that KVM doesn't emulate this MSR and
| the value cannot be used.  This is very similar to handling a #GP in the
| guest, but also has a disadvantage, because KVM cannot say that
| MSR_PLATFORM_INFO is 0.  Simple emulation is not possible.

This patch fix it by using rdmsr_safe to read MSR_PLATFORM_INFO in kvm guest
in order that #GP can be fixed up.

Reported-by: kernel test robot <xiaolong.ye@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Chen Yu <y.c.chen@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: jacob.jun.pan@intel.com
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
 arch/x86/kernel/tsc_msr.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
index e0c2b30..15e06e1 100644
--- a/arch/x86/kernel/tsc_msr.c
+++ b/arch/x86/kernel/tsc_msr.c
@@ -123,8 +123,11 @@ unsigned long cpu_khz_from_msr(void)
  }

 get_ratio:
- rdmsr(MSR_PLATFORM_INFO, lo, hi);
- ratio = (lo >> 8) & 0xff;
+ if (rdmsr_safe(MSR_PLATFORM_INFO, &lo, &hi)) {
+ rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
+ ratio = (hi >> 8) & 0x1f;
+ } else
+ ratio = (lo >> 8) & 0xff;

 done:
  /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */
-- 
1.9.1

[toc] | [prev] | [next] | [standalone]

#1428262

FromWanpeng Li <kernellwp@gmail.com>
Date2016-06-22 01:40 +0200
Message-ID<rMDqW-3ZI-1@gated-at.bofh.it>
In reply to#1427774
2016-06-21 21:59 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
> Hi Paolo,
> 2016-06-21 18:24 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
>> 2016-06-21 18:10 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
>>>
>>>
>>> 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
>
> --------------------
>
> From 8033ae4c7e44d6bfe26642b151de03c613125066 Mon Sep 17 00:00:00 2001
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> Date: Tue, 21 Jun 2016 19:41:12 +0800
> Subject: [PATCH] x86: fix rdmsr MSR_PLATFORM_INFO unsafe warning in kvm guest
>
> From: Wanpeng Li <wanpeng.li@hotmail.com>
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50
> ex_handler_rdmsr_unsafe+0x6a/0x70
> unchecked MSR access error: RDMSR from 0xce
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc3+ #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>  0000000000000000 ffffffff81c03ce0 ffffffff813b3eae ffffffff81c03d30
>  0000000000000000 ffffffff81c03d20 ffffffff81067181 0000003200000001
>  ffffffff81c03df8 ffffffff8179676c 0000000000000000 ffffffff81fcd2c0
> Call Trace:
>  dump_stack+0x67/0x99
>  __warn+0xd1/0xf0
>  warn_slowpath_fmt+0x4f/0x60
>  ex_handler_rdmsr_unsafe+0x6a/0x70
>  fixup_exception+0x39/0x50
>  do_general_protection+0x93/0x1b0
>  general_protection+0x22/0x30
>  ? cpu_khz_from_msr+0xd8/0x1c0
>  native_calibrate_cpu+0x30/0x5b0
>  tsc_init+0x2b/0x297
>  x86_late_time_init+0xf/0x11
>  start_kernel+0x398/0x451
>  ? set_init_arg+0x55/0x55
>  x86_64_start_reservations+0x2f/0x31
>  x86_64_start_kernel+0xea/0xed
>
> After commit (fc141535ad8 : "x86 tsc_msr: Extend to include Intel Core
> Architecture"),
> rdmsr MSR_PLATFORM_INFO is used to get maximum non-turbo ratio for
> recent Intel Core
> Architecture which results in kvm guest rdmsr unsafe warning.
>
> As Radim pointed out before:
>
> | MSR_PLATFORM_INFO: Intel changes it from family to family and there is
> | no obvious overlap or default.  If we picked 0 (any other fixed value),
> | then the guest would have to know that 0 doesn't mean that
> | MSR_PLATFORM_INFO returned 0, but that KVM doesn't emulate this MSR and
> | the value cannot be used.  This is very similar to handling a #GP in the
> | guest, but also has a disadvantage, because KVM cannot say that
> | MSR_PLATFORM_INFO is 0.  Simple emulation is not possible.
>
> This patch fix it by using rdmsr_safe to read MSR_PLATFORM_INFO in kvm guest
> in order that #GP can be fixed up.
>
> Reported-by: kernel test robot <xiaolong.ye@intel.com>
> Cc: Len Brown <len.brown@intel.com>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Chen Yu <y.c.chen@intel.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: jacob.jun.pan@intel.com
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
>  arch/x86/kernel/tsc_msr.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
> index e0c2b30..15e06e1 100644
> --- a/arch/x86/kernel/tsc_msr.c
> +++ b/arch/x86/kernel/tsc_msr.c
> @@ -123,8 +123,11 @@ unsigned long cpu_khz_from_msr(void)
>   }
>
>  get_ratio:
> - rdmsr(MSR_PLATFORM_INFO, lo, hi);
> - ratio = (lo >> 8) & 0xff;
> + if (rdmsr_safe(MSR_PLATFORM_INFO, &lo, &hi)) {
> + rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
> + ratio = (hi >> 8) & 0x1f;

I think this should fallback to PIT calibration instead of
MSR_IA32_PERF_STATUS. In addition, I remember Radim mentioned that
"PERF_CTL the target value for PERF_STATUS, but OS shouldn't put much
trust in those values ... especially under KVM, where those MSRs make
little sense." I will try it today.

Regards,
Wanpeng Li

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web