Questions about function detect_intel_iommu(void)

Questions about function detect_intel_iommu(void)

[Li, Zhen-Hua]

Hi all,
     I am debugging a bug about iommu recently and got a question
about the function detect_intel_opmmu,  Could anybody kindly help me?

     In dmar.c, this function :
                void __init detect_intel_iommu(void)
     In 2.6.32 and redhat enterprise kernel 2.6.18, it is called by
x86_64 system . But in kernel 3.5.2, it is only needed on IA64 system.

    And my question is: is this function really needed for x86_64 and
i386 in 2.6.32?


Thanks and Regards.

Li, Zhen-Hua

Re: Questions about function detect_intel_iommu(void)

[Dave Airlie]

On Mon, Nov 26, 2012 at 4:36 PM, Li, Zhen-Hua <lizhenhua.dev@gmail.com> wrote:
> Hi all,
>      I am debugging a bug about iommu recently and got a question
> about the function detect_intel_opmmu,  Could anybody kindly help me?
>
>      In dmar.c, this function :
>                 void __init detect_intel_iommu(void)
>      In 2.6.32 and redhat enterprise kernel 2.6.18, it is called by
> x86_64 system . But in kernel 3.5.2, it is only needed on IA64 system.
>
>     And my question is: is this function really needed for x86_64 and
> i386 in 2.6.32?

Not sure why you think its IA64, its called from the iommu init code
in 3.x here.

via the IOMMU_INIT_POST macro
Dave.
>
>
> Thanks and Regards.
>
> Li, Zhen-Hua
> --
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Re: Questions about function detect_intel_iommu(void)

[Li, Zhen-Hua]

I read the code of kernel 3.5.2, and found this function is only
called in function void __init pci_iommu_alloc(void) in file
arch/ia64/kernel/pci-dma.c .
So I think it is only called on IA64 system.


On Mon, Nov 26, 2012 at 4:25 PM, Dave Airlie <airlied@gmail.com> wrote:
> On Mon, Nov 26, 2012 at 4:36 PM, Li, Zhen-Hua <lizhenhua.dev@gmail.com> wrote:
>> Hi all,
>>      I am debugging a bug about iommu recently and got a question
>> about the function detect_intel_opmmu,  Could anybody kindly help me?
>>
>>      In dmar.c, this function :
>>                 void __init detect_intel_iommu(void)
>>      In 2.6.32 and redhat enterprise kernel 2.6.18, it is called by
>> x86_64 system . But in kernel 3.5.2, it is only needed on IA64 system.
>>
>>     And my question is: is this function really needed for x86_64 and
>> i386 in 2.6.32?
>
> Not sure why you think its IA64, its called from the iommu init code
> in 3.x here.
>
> via the IOMMU_INIT_POST macro
> Dave.
>>
>>
>> Thanks and Regards.
>>
>> Li, Zhen-Hua
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/