lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 19 Dec 2012 17:21:34 -0600
From:	Jacob Shin <>
To:	Borislav Petkov <>, "H. Peter Anvin" <>,
	Yinghai Lu <>,
	"H. Peter Anvin" <>,
	"Yu, Fenghua" <>,
	"" <>,
	"" <>,
	"" <>,
	Konrad Rzeszutek Wilk <>,
	Stefano Stabellini <>
Subject: Re: [tip:x86/microcode] x86/microcode_intel_early.c: Early update
 ucode on Intel's CPU

On Thu, Dec 20, 2012 at 12:03:29AM +0100, Borislav Petkov wrote:
> On Wed, Dec 19, 2012 at 04:59:41PM -0600, Jacob Shin wrote:
> > I can check but right, they might be used up. But even if we had slots
> > available, the memory range that needs to be covered is in large
> > enough address and aligned in such a way that you cannot cover it with
> > variable range MTRRs.
> Actually, if I'm not mistaken, you only need to cover the HT hole with
> one MTRR - the rest remains WB. And in order the mask bits to work, we
> could make it a little bigger - we waste some memory but that's nothing
> in comparison to the MCE.

Actually all memory hole above 4GB and under TOM2 needs to be marked
as UC, if the kernel just blanket calls init_memory_mapping from 4GB
to top of memory.

Right we would be loosing memory, and I think depending on the
alignment of the boundary and how many MTRRs you have avaiable to use,
significant chunks of memory could be lost. I need to go refresh on
how variable range MTRRs are programmed, it has been a while.

> You might need to talk to hw guys about the feasibility of this deal
> though.
> Thanks.
> -- 
> Regards/Gruss,
>     Boris.
> Sent from a fat crate under my desk. Formatting is fine.
> --

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists