Re: [PATCH] x86/boot: Support uncompressed kernel

[Andy Lutomirski]

On Tue, Mar 28, 2017 at 3:38 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 03/28/17 05:01, Chao Peng wrote:
>>>
>>> I guess the next step would be to use CONFIG_XIP_KERNEL on x86,
>>> which requires an uncompressed kernel but has the additional advantage
>>> of sharing the read-only sections of the kernel image across virtual
>>> machines, resulting in better RAM and cache usage.
>>
>> That is something we wanna look into :)
>>
>
> It is, but that is a second order thing... especially since the x86
> kernel makes heavy use of self-patching at the moment.  What would be
> more significant, though, would be to avoid the memcpy() and instead
> decode the uncompressed kernel in-place.
>

Having looked at this code recently, I'd rather fix it differently:
use the streaming decompression API and integrate it with the ELF
parsing code so we can decompress directly into the actual load
location.  Also, the parse_elf() code needs some serious improved
documentation and robustification.  It's absurdly fragile right now.