Cc KVM ML, Paolo, Radim,

Hi,

On Mon, Jun 20, 2016 at 3:31 PM, kernel test robot
[off-list ref] wrote:

quoted

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-6/19fa5e7364

 7fde1e6a7038a8f05cddf4c43f08d3/0 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

quoted

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