Re: [PATCH] x86, kdump: Set crashkernel_low automatically

From: H. Peter Anvin
Date: Mon Mar 11 2013 - 15:59:07 EST


On 03/11/2013 12:14 PM, Eric W. Biederman wrote:
>
> I don't totally follow the reasoning, but there is one real motivating
> example that is not easy to fix and it has little to do with
> kexec-tools. There is a practical issue that so far the easiest way
> to deal with iommus after a kexec on panic is to just not use them.
> The problem is what to do with existing DMAs transfers that were setup
> by the kernel that crashed and are using the iommu.
>
> When you are loaded above 4G not using iommus can be a challenge.
>

Isn't that what swiotlb is for?

-hpa

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