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SubjectRe: [PATCH qemu] x86: don't let decompressed kernel image clobber setup_data
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On 12/31/22 20:55, Mika Penttilä wrote:
>>
>> If decompression does clobber the data, then we *also* need to figure
>> out why that is. There are basically three possibilities:
>>
>> 1. If physical KASLR is NOT used:
>>
>>      a. The boot loader doesn't honor the kernel safe area properly;
>>      b. Somewhere in the process a bug in the calculation of the
>>         kernel safe area has crept in.
>>
>> 2. If physical KASLR IS used:
>>
>>      The decompressor doesn't correctly keep track of nor relocate
>>      all the keep-out zones before picking a target address.
>
> Seems setup_data is not included in those mem_avoid regions.
>

[facepalm]


>>
>> One is a bootloader bug, two is a kernel bugs. My guess is (2) is the
>> culprit, but (1b) should be checked, too.
>>

Correction: two are kernel bugs, i.e. (1b) and (2) are both kernel bugs.

-hpa

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