lists.openwall.net   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:	Fri, 14 Dec 2007 18:20:04 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	"David P. Reed" <dpreed@...d.com>
CC:	Avi Kivity <avi@...ranet.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	Rene Herman <rene.herman@...access.nl>,
	Pavel Machek <pavel@....cz>,
	kvm-devel <kvm-devel@...ts.sourceforge.net>
Subject: Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80
 on some AMD64x2 laptops, etc.

David P. Reed wrote:
> 
> I believe (though no one seems to have confirming documentation from the 
> chipset or motherboard vendor) that port 80 is actually functional for 
> some unknown function on these machines.   (They do respond to "in" 
> instructions faster than a bus cycle abort does - more evidence).
> 

This is normal.  IN from port 0x80 is used by the DMA address map chip.

As far as I understand, there are other laptops with the same chipset 
which don't have this problem, so it's likely either a motherboard or 
firmware issue.  My guess is that they probably let debugging code out 
in the field (trap port 0x80 in SMM, and then try to output it on some 
debugging bus.)

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists