Re: [Xen-devel] xsave=0 workaround needed on 3.2 kernels with Xen 4.1 or Xen-unstable.

[AP <apxeng@xxxxxxxxx>]

On Wed, May 2, 2012 at 2:00 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 30.04.12 at 21:37, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:
>> I somehow thought that this has been fixed but I've been
>> getting reports that people are running into this.
>
> "this" being what? I too thought that all xsave related issues were
> sorted out by now.

I see the following crash if I run without xsave=0 with Ubuntu 11.10
3.0.0-17 kernel (Intel(R) Core(TM) i7-2620M). I don't see this with
Xen 4.1.2. Looks like the OSXSAVE bit is not getting set in CR4.

[    7.509303] invalid opcode: 0000 [#1] SMP
[    7.509319] CPU 0
[    7.509325] Modules linked in:
[    7.509337]
[    7.509347] Pid: 0, comm: swapper Not tainted 3.0.0-17-generic
#30-Ubuntu LENOVO 4286CTO/4286CTO
[    7.509371] RIP: e030:[<ffffffff810140ec>]  [<ffffffff810140ec>]
xstate_enable+0x3c/0x50
[    7.509399] RSP: e02b:ffffffff81c01e58  EFLAGS: 00010046
[    7.509409] RAX: 0000000000000007 RBX: ffffffff81c01e94 RCX: 0000000000000000
[    7.509419] RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000002660
[    7.509430] RBP: ffffffff81c01e58 R08: ffffffff81c01e90 R09: ffffffff81c01e94
[    7.509440] R10: 00000000ffffffff R11: 00000000ffffffff R12: ffffffff81c01e90
[    7.509501] R13: ffffffff81c01e8c R14: ffffffff81c01e88 R15: ffff8801e97ecd00
[    7.509519] FS:  0000000000000000(0000) GS:ffff8801e97e0000(0000)
knlGS:0000000000000000
[    7.509530] CS:  e033 DS: 0000 ES: 0000 CR0: 000000008005003b
[    7.509539] CR2: 0000000000000000 CR3: 0000000001c03000 CR4: 0000000000002660
[    7.509550] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    7.509561] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[    7.509573] Process swapper (pid: 0, threadinfo ffffffff81c00000,
task ffffffff81c0b020)
[    7.509582] Stack:
[    7.509589]  ffffffff81c01ec8 ffffffff81cd97ac 0000000000000040
0000000000000000
[    7.509613]  ffffffff81007b4f ffffffff81004057 0000024000000007
0000000000000340
[    7.509637]  ffff8801e97eb100 0000000000000008 0000000000000004
0000000000000000
[    7.509660] Call Trace:
[    7.509679]  [<ffffffff81cd97ac>] xstate_enable_boot_cpu+0xa9/0x174
[    7.509698]  [<ffffffff81007b4f>] ? xen_restore_fl_direct_reloc+0x4/0x4
[    7.509712]  [<ffffffff81004057>] ? xen_write_cr0+0x77/0x90
[    7.509730]  [<ffffffff815d06eb>] xsave_init+0x26/0x28
[    7.509744]  [<ffffffff815d2932>] cpu_init+0x2bb/0x2d8
[    7.509759]  [<ffffffff81cd5ff4>] trap_init+0x169/0x171
[    7.509774]  [<ffffffff81cd0a27>] start_kernel+0x1d0/0x3df
[    7.509789]  [<ffffffff81cd0388>] x86_64_start_reservations+0x132/0x136
[    7.509805]  [<ffffffff81cd3ec6>] xen_start_kernel+0x5ac/0x5b3
[    7.509814] Code: 00 04 00 ff 14 25 10 33 c1 81 48 89 c7 48 81 cf
00 00 04 00 ff 14 25 18 33 c1 81 48 8b 05 0d 15 db 00 31 c9 48 89 c2
48 c1 ea 20 <0f> 01 d1 5d c3 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00
00 55
[    7.510045] RIP  [<ffffffff810140ec>] xstate_enable+0x3c/0x50
[    7.510062]  RSP <ffffffff81c01e58>
[    7.510086] ---[ end trace a7919e7f17c0a725 ]---
[    7.510097] Kernel panic - not syncing: Attempted to kill the idle task!
[    7.510109] Pid: 0, comm: swapper Tainted: G      D
3.0.0-17-generic #30-Ubuntu
[    7.510119] Call Trace:
[    7.510134]  [<ffffffff815dca66>] panic+0x91/0x194
[    7.510151]  [<ffffffff8106344b>] do_exit+0x40b/0x440
[    7.510168]  [<ffffffff815f4350>] oops_end+0xb0/0xf0
[    7.510181]  [<ffffffff8100d938>] die+0x58/0x90
[    7.510195]  [<ffffffff815f3a34>] do_trap+0xc4/0x170
[    7.510211]  [<ffffffff8100af25>] do_invalid_op+0x95/0xb0
[    7.510226]  [<ffffffff810140ec>] ? xstate_enable+0x3c/0x50
[    7.510240]  [<ffffffff81007b62>] ? check_events+0x12/0x20
[    7.510255]  [<ffffffff81008239>] ? get_phys_to_machine+0x9/0x70
[    7.510269]  [<ffffffff81005c69>] ? pte_mfn_to_pfn+0x89/0xf0
[    7.510283]  [<ffffffff8100743d>] ? xen_force_evtchn_callback+0xd/0x10
[    7.510299]  [<ffffffff815fc2db>] invalid_op+0x1b/0x20
[    7.510315]  [<ffffffff810140ec>] ? xstate_enable+0x3c/0x50
[    7.510329]  [<ffffffff810140dc>] ? xstate_enable+0x2c/0x50
[    7.510343]  [<ffffffff81cd97ac>] xstate_enable_boot_cpu+0xa9/0x174
[    7.510358]  [<ffffffff81007b4f>] ? xen_restore_fl_direct_reloc+0x4/0x4
[    7.510371]  [<ffffffff81004057>] ? xen_write_cr0+0x77/0x90
[    7.510385]  [<ffffffff815d06eb>] xsave_init+0x26/0x28
[    7.510399]  [<ffffffff815d2932>] cpu_init+0x2bb/0x2d8
[    7.510413]  [<ffffffff81cd5ff4>] trap_init+0x169/0x171
[    7.510427]  [<ffffffff81cd0a27>] start_kernel+0x1d0/0x3df
[    7.510441]  [<ffffffff81cd0388>] x86_64_start_reservations+0x132/0x136
[    7.510457]  [<ffffffff81cd3ec6>] xen_start_kernel+0x5ac/0x5b3
(XEN) Domain 0 crashed: rebooting machine in 5 seconds.
(XEN) Resetting with ACPI MEMORY or I/O RESET_REG.


>> What kind of fix do I need the in the kernel? I see this:
>>  255         xen_cpuid(&ax, &bx, &cx, &dx);
>>  256
>>  257         xsave_mask =
>>  258                 (1 << (X86_FEATURE_XSAVE % 32)) |
>>  259                 (1 << (X86_FEATURE_OSXSAVE % 32));
>>  260
>>  261         /* Xen will set CR4.OSXSAVE if supported and not disabled by
>> force */
>>  262         if ((cx & xsave_mask) != xsave_mask)
>>  263                 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE &
>> OSXSAVE */
>>  264 }
>>
>> But do I need some other one?
>
>
>
>
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