Re: [PATCH] x86/kexec: always ensure EFI systab region is mapped

Junichi Nomura
2019-04-23T06:21:17Z

On 4/22/19 6:28 PM, Kairui Song wrote:
> The reason is the systab region is not mapped by the identity mapping
> provided by kexec. Currently kexec only create identity mapping for
> mem regions, wihch won't cover the systab. So second kernel will be
> accessing a not mapped memory region and cause fault.
> But as kexec tend to pad the map region up to PUD size, the
> systab could be included in the map by accident, so it worked on
> some machines, but that will be broken easily and unstable.

Is the mapping of ACPI tables just by luck, too?

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Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.