Ask for help about the smmu initialization process in the kdump crash kernel

[Liu Song]

Hi，

Does any suggestions for this question? Looking forward to your reply.

Thanks


在 2022/12/21 16:22, Liu Song 写道:
> Hi
>
> We encountered such a problem in our environment. When a kernel panic 
> occurs,
> the DPU still has access to the host device under the kdump crash 
> kernel, but the
> content of the smmu has been cleared during the startup of the crash 
> kernel, thus
> causing errors. Referring to the implementation of X86 here, it will 
> judge whether is
> a crash kernel, and if it is, it will copy the previous IOMMU page 
> table content.
>
> What we want to ask is whether arm64 can also operate in this way to 
> maintain the
> previous page table content of the device under the crash kernel, and 
> are there any
> problems that cannot be solved by the smmu mechanism in the 
> implementation?
>
>
> Thanks
>