Re: [PATCH v8 0/3] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory

From: Masayoshi Mizuma
Date: Thu Oct 25 2018 - 09:41:02 EST

On Thu, Oct 25, 2018 at 12:33:45PM +0200, Borislav Petkov wrote:
> On Mon, Oct 22, 2018 at 11:42:05AM -0400, Masayoshi Mizuma wrote:
> > I'm trying to store the SRAT info and pass it to kernel_randomize_memory(),
> > looks like add_e820ext()/parse_setup_data().
> >
> > Is the approach useful only EFI environment? I'm not sure how I
> Does it matter for non-EFI even?
> I mean, you want this code only for your use case - when you have
> movable memory and you're doing kexec, yes?
> And those machines are all EFI boxes I'd assume...

My actual use case is for EFI boxes, however, I think it's better to useful
for legacy BIOS as well because memory hot-plug affinity in SRAT and KASLR
are available on legacy BIOS.
Actually, we can create such environment in qemu.

I have another idea to solve this issue. Adding a SRAT parsing code
to arch/x86/mm/kaslr.c. It is useful for both EFI and BIOS and
also we don't need a new kernel parameter...
Dose the idea make sense?