Re: [PATCH 2/5 V6] x86/ioremap: strengthen the logic in early_memremap_pgprot_adjust() to adjust encryption mask

From: lijiang
Date: Wed Sep 05 2018 - 10:05:09 EST


å 2018å09æ05æ 14:46, Dave Young åé:
> [snip]
>>
>> As previously mentioned, there are also many differences between kexec and kdump. In general,
>> kexec needs to look at all of available physical memory, but kdump doesn't need.
>>
>> For kexec, kexec-tools will read /sys/firmware/memmap and recreate the e820 ranges for the 2nd
>> kernel. If it fails, will use /proc/iomem.
>>
>> For kdump, kexec-tools will read /proc/iomem and recreate the e820 ranges for kdump kernel.
>> BTW: we can not get the range of persistent memory from /proc/iomem. So e820 ranges don't contain
>> the persistent memory in kdump kernel, this is the real reason why i need to strengthen the logic
>> of adjusting memory encryption mask.
>
> "persistent memory" is different, I think you meant about some reserved
> memory instead
>
>>
>> If kexec-tools also use /sys/firmware/memmap for kdump(like kexec), kdump kernel can also work
>> without a fix, but the kexec-tools will have to be modified. Are you sure that you want me to
>> fix kexec-tools instead of kernel?
>
> Yes, please fix kexec-tools to pass reserved ranges in e820, you will
> not need this patch then.
>

This might be a kexec-tools bug, i have posted a patch for kexec-tools(please check kexec@xxxxxxxxxxxxxxxxxxx).
Thanks.

> Thanks
> Dave
>