On 2016-07-23 03:20, Marc Zyngier wrote: > On Sat, 23 Jul 2016 00:45:50 -0700 > Stefan Agner <stefan@xxxxxxxx> wrote: > >> On 2016-07-22 11:11, Marc Zyngier wrote: >> > On 22/07/16 18:56, Stefan Agner wrote: >> >> On 2016-07-22 10:49, Marc Zyngier wrote: >> >>> On 22/07/16 18:38, Andrew Jones wrote: >> >>>> On Fri, Jul 22, 2016 at 04:40:15PM +0100, Marc Zyngier wrote: >> >>>>> On 22/07/16 15:35, Andrew Jones wrote: >> >>>>>> On Fri, Jul 22, 2016 at 11:42:02AM +0100, Andre Przywara wrote: >> >>>>>>> Hi Stefan, >> >>>>>>> >> >>>>>>> On 22/07/16 06:57, Stefan Agner wrote: >> >>>>>>>> Hi, >> >>>>>>>> >> >>>>>>>> I tried KVM on a Cortex-A7 platform (i.MX 7Dual SoC) and encountered >> >>>>>>>> this stack trace immediately after invoking qemu-system-arm: >> >>>>>>>> >> >>>>>>>> Unable to handle kernel paging request at virtual address ffffffe4 >> >>>>>>>> pgd = 8ca52740 >> >>>>>>>> [ffffffe4] *pgd=80000080007003, *pmd=8ff7e003, *pte=00000000 >> >>>>>>>> Internal error: Oops: 207 [#1] SMP ARM >> >>>>>>>> Modules linked in: >> >>>>>>>> CPU: 0 PID: 329 Comm: qemu-system-arm Tainted: G W >> >>>>>>>> 4.7.0-rc7-00094-gea3ed2c #109 >> >>>>>>>> Hardware name: Freescale i.MX7 Dual (Device Tree) >> >>>>>>>> task: 8ca3ee40 ti: 8d2b0000 task.ti: 8d2b0000 >> >>>>>>>> PC is at do_raw_spin_lock+0x8/0x1dc >> >>>>>>>> LR is at kvm_vgic_flush_hwstate+0x8c/0x224 >> >>>>>>>> pc : [<8027c87c>] lr : [<802172d4>] psr: 60070013 >> >>>>>>>> sp : 8d2b1e38 ip : 8d2b0000 fp : 00000001 >> >>>>>>>> r10: 8d2b0000 r9 : 00010000 r8 : 8d2b8e54 >> >>>>>>>> fec 30be0000.ethernet eth0: MDIO read timeout >> >>>>>>>> r7 : 8d2b8000 r6 : 8d2b8e74 r5 : 00000000 r4 : ffffffe0 >> >>>>>>>> r3 : 00004ead r2 : 00000000 r1 : 00000000 r0 : ffffffe0 >> >>>>>>>> Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user >> >>>>>>>> Control: 30c5387d Table: 8ca52740 DAC: fffffffd >> >>>>>>>> Process qemu-system-arm (pid: 329, stack limit = 0x8d2b0210) >> >>>>>>>> Stack: (0x8d2b1e38 to 0x8d2b2000) >> >>>>>>>> 1e20: ffffffe0 >> >>>>>>>> 00000000 >> >>>>>>>> 1e40: 8d2b8e74 8d2b8000 8d2b8e54 00010000 8d2b0000 802172d4 8d2b8000 >> >>>>>>>> 810074f8 >> >>>>>>>> 1e60: 81007508 8ca5f800 8d284000 00010000 8d2b0000 8020fbd4 8ce9a000 >> >>>>>>>> 8ca5f800 >> >>>>>>>> 1e80: 00000000 00010000 00000000 00ff0000 8d284000 00000000 00000000 >> >>>>>>>> 7ffbfeff >> >>>>>>>> 1ea0: fffffffe 00000000 8d28b780 00000000 755fec6c 00000000 00000000 >> >>>>>>>> ffffe000 >> >>>>>>>> 1ec0: 8d2b8000 00000000 8d28b780 00000000 755fec6c 8020af90 00000000 >> >>>>>>>> 8023f248 >> >>>>>>>> 1ee0: 0000000a 755fe98c 8d2b1f08 00000008 8021aa84 ffffe000 00000000 >> >>>>>>>> 00000000 >> >>>>>>>> 1f00: 8a00d860 8d28b780 80334f94 00000000 8d2b0000 80334748 00000000 >> >>>>>>>> 00000000 >> >>>>>>>> 1f20: 00000000 8d28b780 00004000 00000009 8d28b500 00000024 8104ebee >> >>>>>>>> 80bc2ec4 >> >>>>>>>> 1f40: 80bafa24 8034138c 00000000 00000000 80341248 00000000 755fec6c >> >>>>>>>> 007c1e70 >> >>>>>>>> 1f60: 00000009 00004258 0000ae80 8d28b781 00000009 8d28b780 0000ae80 >> >>>>>>>> 00000000 >> >>>>>>>> 1f80: 8d2b0000 00000000 755fec6c 80334f94 007c1e70 322a7400 00004258 >> >>>>>>>> 00000036 >> >>>>>>>> 1fa0: 8021aa84 8021a900 007c1e70 322a7400 00000009 0000ae80 00000000 >> >>>>>>>> 755feac0 >> >>>>>>>> 1fc0: 007c1e70 322a7400 00004258 00000036 7e9aff58 01151da4 76f8b4c0 >> >>>>>>>> 755fec6c >> >>>>>>>> 1fe0: 0038192c 755fea9c 00048ae7 7697d66c 60070010 00000009 00000000 >> >>>>>>>> 00000000 >> >>>>>>>> [<8027c87c>] (do_raw_spin_lock) from [<802172d4>] >> >>>>>>>> (kvm_vgic_flush_hwstate+0x8c/0x224) >> >>>>>>>> [<802172d4>] (kvm_vgic_flush_hwstate) from [<8020fbd4>] >> >>>>>>>> (kvm_arch_vcpu_ioctl_run+0x110/0x478) >> >>>>>>>> [<8020fbd4>] (kvm_arch_vcpu_ioctl_run) from [<8020af90>] >> >>>>>>>> (kvm_vcpu_ioctl+0x2e0/0x6d4) >> >>>>>>>> [<8020af90>] (kvm_vcpu_ioctl) from [<80334748>] >> >>>>>>>> (do_vfs_ioctl+0xa0/0x8b8) >> >>>>>>>> [<80334748>] (do_vfs_ioctl) from [<80334f94>] (SyS_ioctl+0x34/0x5c) >> >>>>>>>> [<80334f94>] (SyS_ioctl) from [<8021a900>] (ret_fast_syscall+0x0/0x1c) >> >>>>>>>> Code: e49de004 ea09ea24 e92d47f0 e3043ead (e5902004) >> >>>>>>>> ---[ end trace cb88537fdc8fa206 ]--- >> >>>>>>>> >> >>>>>>>> I use CONFIG_KVM_NEW_VGIC=y. This happens to me with a rather minimal >> >>>>>>>> qemu invocation (qemu-system-arm -enable-kvm -M virt -cpu host >> >>>>>>>> -nographic -serial stdio -kernel zImage). >> >>>>>>>> >> >>>>>>>> Using a bit older Qemu version 2.4.0. >> >>>>>>> >> >>>>>>> I just tried with a self compiled QEMU 2.4.0 and the Ubuntu 14.04 >> >>>>>>> provided 2.0.0, it worked fine with Linus' current HEAD as a host kernel >> >>>>>>> on a Midway (Cortex-A15). >> >>>>>> >> >>>>>> I can reproduce the issue with a latest QEMU build on AMD Seattle >> >>>>>> (I haven't tried anywhere else yet) >> >>>>>> >> >>>>>>> >> >>>>>>> Can you try to disable the new VGIC, just to see if that's a regression? >> >>>>>> >> >>>>>> Disabling NEW_VGIC "fixes" guest boots. >> >>>>>> >> >>>>>> I'm not using defconfig for my host kernel. I'll do a couple more >> >>>>>> tests and provide a comparison of my config vs. a defconfig in >> >>>>>> a few minutes. >> >>>>> >> >>>>> Damn. It is not failing for me, so it has to be a kernel config thing... >> >>>>> If you can narrow it down to the difference with defconfig, that'd be >> >>>>> tremendously helpful. >> >>>> >> >>>> It's PAGE_SIZE; 64K doesn't work, 4K does, regardless of VA_BITS >> >>>> selection. >> >>> >> >>> That definitely doesn't match Stefan's report (32bit only has 4k). I'll >> >> >> >> Hehe, was just plowing through code and came to that conclusion, glad I >> >> got that right :-) >> >> >> >> What defconfig do you use? I could reproduce the issue also with >> >> multi_v7_defconfig + ARM_LPAE + KVM. >> > >> > I have my own config file with the crap I need to make things work on >> > the various platforms I have around. If multi_v7_defconfig works on the >> > cubietruck, I'll give it a spin tomorrow. I need a beer now. >> > >> >> Btw, I am not exactly on vanilla 4.7-rc7, I merged Shawns for-next + >> >> clock next to get to the bits and pieces required for my board... >> >> >> >> That said, it works fine otherwise, and the stacktrace looks rather >> >> platform independent... >> > >> > Yeah, and that's the worrying part. >> >> >> FWIW, I tried here with Qemu 2.6.0, same stack trace... > > I don't think this is userspace related, specially given that Andrew > managed to trigger it on arm64 as well. I guess we're looking at > something that changes the layout of memory (page size in Drew's case), > and exposes another latent bug. I'll try to get multi_v7_defconfig > running on my CT later today, and hopefully the thing will explode. > Fingers crossed. > I hit another issue, this time in the guest. At times, it seemed as if qemu-system-arm freezed (no console output). I then enabled earlyprintk for PL01X UART, and got this: Architected timer frequency not available ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/time/clockevents.c:44 cev_delta2ns+0x114/0x128 Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0-rc7 #5 Hardware name: Generic DT based system [<8010e2a0>] (unwind_backtrace) from [<8010b270>] (show_stack+0x10/0x14) [<8010b270>] (show_stack) from [<8030e734>] (dump_stack+0x84/0x98) [<8030e734>] (dump_stack) from [<8011a718>] (__warn+0xe8/0x100) [<8011a718>] (__warn) from [<8011a7e0>] (warn_slowpath_null+0x20/0x28) [<8011a7e0>] (warn_slowpath_null) from [<8017503c>] (cev_delta2ns+0x114/0x128) [<8017503c>] (cev_delta2ns) from [<8017548c>] (clockevents_config.part.2+0x4c/0x6c) [<8017548c>] (clockevents_config.part.2) from [<801754cc>] (clockevents_config_and_register+0x20/0x2c) [<801754cc>] (clockevents_config_and_register) from [<80435d9c>] (arch_timer_setup+0xd8/0x1b4) [<80435d9c>] (arch_timer_setup) from [<8081c118>] (arch_timer_of_init+0x2a0/0x2c8) [<8081c118>] (arch_timer_of_init) from [<8081bb14>] (clocksource_probe+0x54/0x90) [<8081bb14>] (clocksource_probe) from [<80800b30>] (start_kernel+0x240/0x378) [<80800b30>] (start_kernel) from [<4000807c>] (0x4000807c) ---[ end trace cb88537fdc8fa200 ]--- Architected cp15 timer(s) running at 0.00MHz (virt). Division by zero in kernel. CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.7.0-rc7 #5 Hardware name: Generic DT based system [<8010e2a0>] (unwind_backtrace) from [<8010b270>] (show_stack+0x10/0x14) [<8010b270>] (show_stack) from [<8030e734>] (dump_stack+0x84/0x98) [<8030e734>] (dump_stack) from [<8030c764>] (Ldiv0_64+0x8/0x18) [<8030c764>] (Ldiv0_64) from [<80172360>] (clocks_calc_max_nsecs+0x24/0x78) [<80172360>] (clocks_calc_max_nsecs) from [<801725d8>] (__clocksource_update_freq_scale+0x224/0x2fc) [<801725d8>] (__clocksource_update_freq_scale) from [<801726c4>] (__clocksource_register_scale+0x14/0xa8) [<801726c4>] (__clocksource_register_scale) from [<8081be20>] (arch_timer_common_init+0x1d8/0x230) [<8081be20>] (arch_timer_common_init) from [<8081c0dc>] (arch_timer_of_init+0x264/0x2c8) [<8081c0dc>] (arch_timer_of_init) from [<8081bb14>] (clocksource_probe+0x54/0x90) [<8081bb14>] (clocksource_probe) from [<80800b30>] (start_kernel+0x240/0x378) [<80800b30>] (start_kernel) from [<4000807c>] (0x4000807c) clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x0, max_idle_ns: 0 ns Division by zero in kernel. CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.7.0-rc7 #5 Hardware name: Generic DT based system [<8010e2a0>] (unwind_backtrace) from [<8010b270>] (show_stack+0x10/0x14) [<8010b270>] (show_stack) from [<8030e734>] (dump_stack+0x84/0x98) [<8030e734>] (dump_stack) from [<8030c764>] (Ldiv0_64+0x8/0x18) [<8030c764>] (Ldiv0_64) from [<80172288>] (clocks_calc_mult_shift+0x11c/0x13c) [<80172288>] (clocks_calc_mult_shift) from [<8080a388>] (sched_clock_register+0x64/0x1d8) [<8080a388>] (sched_clock_register) from [<8081be54>] (arch_timer_common_init+0x20c/0x230) [<8081be54>] (arch_timer_common_init) from [<8081c0dc>] (arch_timer_of_init+0x264/0x2c8) [<8081c0dc>] (arch_timer_of_init) from [<8081bb14>] (clocksource_probe+0x54/0x90) [<8081bb14>] (clocksource_probe) from [<80800b30>] (start_kernel+0x240/0x378) [<80800b30>] (start_kernel) from [<4000807c>] (0x4000807c) Division by zero in kernel. CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.7.0-rc7 #5 Hardware name: Generic DT based system [<8010e2a0>] (unwind_backtrace) from [<8010b270>] (show_stack+0x10/0x14) [<8010b270>] (show_stack) from [<8030e734>] (dump_stack+0x84/0x98) [<8030e734>] (dump_stack) from [<8030c764>] (Ldiv0_64+0x8/0x18) [<8030c764>] (Ldiv0_64) from [<80172360>] (clocks_calc_max_nsecs+0x24/0x78) [<80172360>] (clocks_calc_max_nsecs) from [<8080a3cc>] (sched_clock_register+0xa8/0x1d8) [<8080a3cc>] (sched_clock_register) from [<8081be54>] (arch_timer_common_init+0x20c/0x230) [<8081be54>] (arch_timer_common_init) from [<8081c0dc>] (arch_timer_of_init+0x264/0x2c8) [<8081c0dc>] (arch_timer_of_init) from [<8081bb14>] (clocksource_probe+0x54/0x90) [<8081bb14>] (clocksource_probe) from [<80800b30>] (start_kernel+0x240/0x378) [<80800b30>] (start_kernel) from [<4000807c>] (0x4000807c) sched_clock: 56 bits at 0 Hz, resolution 0ns, wraps every 0ns Console: colour dummy device 80x30 Calibrating delay loop... When it works (which tends to be around every 5. try), then the clock of the Architected timer seems to be correctly identified: Architected cp15 timer(s) running at 8.00MHz (virt). Host looks good: # dmesg | grep Architected [ 0.000000] Architected cp15 timer(s) running at 8.00MHz (phys). Afaict, U-Boot correctly initializes the timers frequency in arch/arm/imx-common/syscounter.c. The guest is using a vanilla v4.7-rc7 kernel. The host is running without CONFIG_KVM_NEW_VGIC. Looks like some kind of race during initialization...? Related to the new VGIC issue? -- Stefan _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
