Messages in this thread | | | Subject | Re: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier | From | Dou Liyang <> | Date | Fri, 28 Jul 2017 10:28:34 +0800 |
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Hi, Zheng
At 07/28/2017 09:53 AM, Zheng, Lv wrote: [...] >> >>> Dmar hardware support interrupt remapping and io remapping separately. But >>> intel_iommu_init() is called later than intel_prepare_irq_remapping(). >>> So what if make dmar_table_init() a reentrant function? You can just >>> have a try, but maybe not a good idea, the dmar table will be parsed >>> twice. >> >> Yes, It is precisely one reason that I gave up invoking >> acpi_put_table(). > > Parsing a table twice is not a problem on x86. > If you check the code, there are many examples. > It's actually required if you want to use a table both in early stage and late stage. >
I am sorry I don't explain clearly.
Yeah, in current kernel, The DMAR table has been parsed twice as well. one is in detect_intel_iommu(), the other is in dmar_table_init().
Here we focus on the reentrant dmar_table_init(), this func contains many callback for parsing different DMAR type structures, such as DRHD, RMRR.
acpi_put_table() can release the mapped DMAR address, but we should clear the remapping structure types manually. and I think parsing these DMAR type structures again may have an influence on interrupt remapping.
Thanks,
dou.
> Thanks > >> >> Thanks, >> >> dou. >> >>> >>>> >>>> >>>> Thanks, >>>> >>>> dou. >>>>> >>>>> Thanks >>>>> Lv >>>>> >>>>>> From: Dou Liyang [mailto:douly.fnst@cn.fujitsu.com] >>>>>> Sent: Friday, July 14, 2017 1:53 PM >>>>>> To: x86@kernel.org; linux-kernel@vger.kernel.org >>>>>> Cc: tglx@linutronix.de; mingo@kernel.org; hpa@zytor.com; ebiederm@xmission.com; bhe@redhat.com; >>>>>> peterz@infradead.org; izumi.taku@jp.fujitsu.com; tokunaga.keiich@jp.fujitsu.com; Dou Liyang >>>>>> <douly.fnst@cn.fujitsu.com>; linux-acpi@vger.kernel.org; Rafael J. Wysocki <rjw@rjwysocki.net>; >> Zheng, >>>>>> Lv <lv.zheng@intel.com>; Julian Wollrath <jwollrath@web.de> >>>>>> Subject: [PATCH v7 12/13] ACPI / init: Invoke early ACPI initialization earlier >>>>>> >>>>>> Linux uses acpi_early_init() to put the ACPI table management into >>>>>> the late stage from the early stage where the mapped ACPI tables is >>>>>> temporary and should be unmapped. >>>>>> >>>>>> But, now initializing interrupt delivery mode should map and parse the >>>>>> DMAR table earlier in the early stage. This causes an ACPI error when >>>>>> Linux reallocates the ACPI root tables. Because Linux doesn't unmapped >>>>>> the DMAR table after using in the early stage. >>>>>> >>>>>> Invoke acpi_early_init() earlier before late_time_init(), Keep the DMAR >>>>>> be mapped and parsed in late stage like before. >>>>>> >>>>>> Reported-by: Xiaolong Ye <xiaolong.ye@intel.com> >>>>>> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> >>>>>> Cc: linux-acpi@vger.kernel.org >>>>>> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> >>>>>> Cc: Zheng, Lv <lv.zheng@intel.com> >>>>>> Cc: Julian Wollrath <jwollrath@web.de> >>>>>> --- >>>>>> Test in my own PC(Lenovo M4340). >>>>>> Ask help for doing regression testing for the bug said in commit c4e1acbb35e4 >>>>>> ("ACPI / init: Invoke early ACPI initialization later"). >>>>>> >>>>>> init/main.c | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/init/main.c b/init/main.c >>>>>> index df58a41..7a09467 100644 >>>>>> --- a/init/main.c >>>>>> +++ b/init/main.c >>>>>> @@ -654,12 +654,12 @@ asmlinkage __visible void __init start_kernel(void) >>>>>> kmemleak_init(); >>>>>> setup_per_cpu_pageset(); >>>>>> numa_policy_init(); >>>>>> + acpi_early_init(); >>>>>> if (late_time_init) >>>>>> late_time_init(); >>>>>> calibrate_delay(); >>>>>> pidmap_init(); >>>>>> anon_vma_init(); >>>>>> - acpi_early_init(); >>>>>> #ifdef CONFIG_X86 >>>>>> if (efi_enabled(EFI_RUNTIME_SERVICES)) >>>>>> efi_enter_virtual_mode(); >>>>>> -- >>>>>> 2.5.5 >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>>> >>> >>> >>> >> > > > >
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