RE: [Xen-devel] RE: [Xen-users] Xen in a 32 way system

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

The line you have the BUG in is a VCPUOP_initialize, which ends up in
.../xen/common/domain.c: do_vcpu_op(), where it does essentially the
first thing is a check:
        if ((vcpuid < 0) || (vcpuid >= MAX_VIRT_CPUS))
                return -EINVAL;

And I think this check will fail if vcpuid is 32, unless MAX_VIRT_CPUS
is not the standard value in . RSI is 32 (0x20)

As per this code:
ffff830000106d8c:       83 fe 1f                cmp    $0x1f,%esi
ffff830000106d8f:       41 89 f4                mov    %esi,%r12d
ffff830000106d92:       49 89 d5                mov    %rdx,%r13
ffff830000106d95:       48 8b 58 10             mov    0x10(%rax),%rbx
ffff830000106d99:       48 c7 c0 ea ff ff ff    mov
$0xffffffffffffffea,%rax
ffff830000106da0:       0f 87 9d 01 00 00       ja     ffff830000106f43
<do_vcpu_op+0x1f3>

So it seems like you're trying to start MORE than 32 CPUS to me... Don't
know why... Or is this check bogus? It doesn't look bogus to me... 

By the way, this is a "bug" in XEN-code inside the linux-kernel, so it's
not a because of the general 2.6.16.13 kernel code, and I suspect you'd
hit the same thing with a slightly earlier kernel - although this code
is something I haven't looked much at before - maybe it silently ignored
error-returns from this call before... 

--
Mats

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Pablo Montesinos
> Sent: 01 June 2006 17:11
> To: Ryan Harper
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; Uros Trebec; 
> Puthiyaparambil, Aravindh; xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] RE: [Xen-users] Xen in a 32 way system
> 
> I installed xen-unstable and it seems to solve that problem. 
> However, I am getting a kernel bug. xen-unstable downloaded 
> the 2.6.16.13 kernel. It is possible to use a 2.6.16?
> 
> Thanks,
> Pablo
> 
> PS: if you enjoy kernel bugs:
> 
> 
> Kernel BUG at drivers/xen/core/smpboot.c:224 invalid opcode: 
> 0000 [1] SMP CPU 0 Modules linked in:
> Pid: 1, comm: swapper Not tainted 2.6.16.13-xen #2
> RIP: e030:[<ffffffff802c5d15>] 
> <ffffffff802c5d15>{cpu_initialize_context+514}
> RSP: e02b:ffff8800018bca78  EFLAGS: 00010282
> RAX: ffffffffffffffea RBX: ffff8800018bca88 RCX: 0000000000000101
> RDX: ffff8800018bca88 RSI: 0000000000000020 RDI: 0000000000000000
> RBP: ffff8800018bdee8 R08: ffff8800102b5a20 R09: 0000000000000000
> R10: ffff8800018bca88 R11: 0000000000000200 R12: 0000000000000020
> R13: 0000000000000140 R14: ffff8800102b5860 R15: ffffffff8040be40
> FS:  0000000000000000(0000) GS:ffffffff8052f000(0000) 
> knlGS:0000000000000000
> CS:  e033 DS: 0000 ES: 0000
> Process swapper (pid: 1, threadinfo ffff8800018bc000, task 
> ffff8800018a4760)
> Stack: 00000000002fab4f 0000000000000020 0000000000000000 
> 0000000000000000
>        0000000000000000 0000000000000000 0000000000000000 
> 0000000000000000
>        0000000000000000 0000000000000000 Call Trace: 
> <ffffffff802c5adb>{cpu_bringup+0} <ffffffff8010b758>{divide_error+0}
>        <ffffffff80398fa4>{debug+0} <ffffffff80398fc0>{int3+0}
>        <ffffffff8010b65c>{overflow+0} <ffffffff8010b678>{bounds+0}
>        <ffffffff8010b694>{invalid_op+0}
> <ffffffff8010b640>{device_not_available+0}
>        <ffffffff8010b6b0>{coprocessor_segment_overrun+0}
> <ffffffff8010b6e8>{invalid_TSS+0}
>        <ffffffff8010b704>{segment_not_present+0}
> <ffffffff8010b720>{stack_segment+0}
>        <ffffffff80398fdc>{general_protection+0} 
> <ffffffff80398f88>{page_fault+0}
>        <ffffffff8010b774>{spurious_interrupt_bug+0}
> <ffffffff8010b608>{coprocessor_error+0}
>        <ffffffff8010b73c>{alignment_check+0}
> <ffffffff8010b624>{simd_coprocessor_error+0}
>        <ffffffff8011b2e8>{ia32_syscall+0}
> <ffffffff8010b2a4>{hypervisor_callback+0}
>        <ffffffff8010b3a4>{failsafe_callback+0} 
> <ffffffff8010aa94>{system_call+0}
>        <ffffffff80564e5f>{smp_prepare_cpus+456} 
> <ffffffff80108084>{init+60}
>        <ffffffff8010b532>{child_rip+8}
> <ffffffff80275580>{acpi_ds_init_one_object+0}
>        <ffffffff80108048>{init+0} <ffffffff8010b52a>{child_rip+0}
> 
> Code: 0f 0b 68 e2 61 3d 80 c2 e0 00 48 81 c4 48 14 00 00 5b 
> 41 5c RIP <ffffffff802c5d15>{cpu_initialize_context+514} RSP 
> <ffff8800018bca78>  <0>Kernel panic - not syncing: Attempted 
> to kill init!
>  (XEN) Domain 0 crashed: rebooting machine in 5 seconds.
> (XEN) Reboot disabled on cmdline: require manual reset
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
> 
> 


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