Re: [Xen-devel] [x86/time] 03fa63cc96: ACPI_Error:Table[DMAR]is_not_invalidated_during_early_boot_stage(#/tbxface -#)

[Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>]

Hi Thomas,

At 07/07/2017 11:04 AM, Ye Xiaolong wrote:
> On 07/07, Dou Liyang wrote:
> > Hi xiaolong,
> >
> > Really thanks for your testing.
> >
> > At 07/07/2017 09:54 AM, Ye Xiaolong wrote:
> > > On 07/06, Thomas Gleixner wrote:
> > > > On Thu, 6 Jul 2017, kernel test robot wrote:
> > > >
> > > > > commit: 03fa63cc96ab35592e0a7d522b8edbc1e6b02d22 ("x86/time: Initialize interrupt 
> > > > > mode behind timer init")
> > > > > +----------------+------------+------------+
> > > > > |                | 43436935b7 | 03fa63cc96 |
> > > > > +----------------+------------+------------+
> > > > > | boot_successes | 0          | 4          |
> > > > > +----------------+------------+------------+
> > > > So 03fa63cc96 makes the box boot again. I'm confused as usual by the
> > > > output of this tool.,
> > > >
> > > > > kern  :info  : [    0.005000] tsc: Fast TSC calibration using PIT
> > > > > kern  :info  : [    0.006000] tsc: Detected 2195.020 MHz processor
> > > > > kern  :info  : [    0.007000] Calibrating delay loop (skipped), value 
> > > > > calculated using timer frequency.. 4390.04 BogoMIPS (lpj=2195020)
> > > > > kern  :info  : [    0.008001] pid_max: default: 90112 minimum: 704
> > > > > kern  :info  : [    0.009037] ACPI: Core revision 20170303
> > > > > kern  :err   : [    0.010002] ACPI Error: Table [DMAR] is not invalidated 
> > > > > during early boot stage (20170303/tbxface-193)
> > > > Sure we have a error message here, but compared to what? Compared to
> > > > something which does not boot at all?
> > > Sorry for the confusion, here commit 43436935b7 boot failed due to OOM which
> > > happened at the late stage of kernel boot while the ACPI error showed at the
> > > early boot stage for commit 03fa63cc96 and it didn't appear in 43436935b7's
> > > dmesg.
> > let's make the problem clearly firstly:
> >
> > 1) Commit 43436935b7 ("x86/xen: Bypass intr mode setup in enlighten_pv
> > system") made kernel boot failed, which caused by OOM.
It is so interesting!

This patch only work for XEN in pv mode, if we boot a kernel w/o XEN,
it will not work in fact.


> > 2) Commit 03fa63cc96 ("x86/time: Initialize interrupt mode behind
> > timer init") can make the kernel boot success again, but with an ACPI
> > error happened.
Indeed, the ACPI Error appeared with this patch.

If x2apic is enabled in x86-64, initializing interrupt mode contains
irq remapping setup and the ACPI DMAR table initialization.

default_setup_apic_routing()
  enable_IR_x2apic()
    irq_remapping_prepare()
      intel_prepare_irq_remapping()
        dmar_table_init()

this patch make interrupt mode setup before acpi_early_init() which has
the check of ACPI table state in acpi_reallocate_root_table() where the
ACPI Error generated.

I have got a machine which supports x2apic. I am tracking the code,
try to find out more.

Thanks,

        dou.
> > And both *1* and *2* used the same configuration showed in the
> > attachment.
> >
> > Does anything I missed?
> Yes, this is exactly what I meant.
>
> Thanks,
> Xiaolong
> > Thanks,
> >
> >         dou.
> >
> > > Thanks,
> > > Xiaolong
> > >
> > > > Thanks,
> > > >
> > > >         tglx


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