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

From: Dou Liyang
Date: Fri Jul 07 2017 - 00:46:55 EST

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

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.


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.



And both *1* and *2* used the same configuration showed in the

Does anything I missed?

Yes, this is exactly what I meant.