linux-kernel - Re: [GIT PULL] x86/boot changes for v6.10

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Date: Wed, 15 May 2024 10:09:56 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Ard Biesheuvel <ardb@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	the arch/x86 maintainers <x86@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [GIT PULL] x86/boot changes for v6.10


* Ard Biesheuvel <ardb@...nel.org> wrote:

> On Tue, 14 May 2024 at 03:03, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
> >
> > On Sun, 12 May 2024 at 23:51, Ingo Molnar <mingo@...nel.org> wrote:
> > >
> > >  - Re-introduce a bootloader quirk wrt. CR4 handling
> >
> > I've pulled this, but shouldn't the compressed boot also just stop
> > setting the G flag that it didn't understand?
> >
> 
> I agree. But not setting CR4 to a known value is what caused the
> regression, and that could cause other problems down the road, so
> fixing it was arguably more important.
> 
> More than happy to send another patch to clear the G bit from the page
> table entries created by the decompressor, but at this point, it
> shouldn't make a difference.

Please - we shouldn't be creating page table entries with random G bits set 
in them. The boot code should at least pretend to maintain the illusion 
that it knows what it's doing. ;-)

Thanks,

	Ingo