linux-kernel - Re: [Xen-devel] [PATCH 3/3] x86/xen: sync the CMOS RTC as well as the Xen wallclock

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <51927F2002000078000D6224@nat28.tlf.novell.com>
Date:	Tue, 14 May 2013 17:14:56 +0100
From:	"Jan Beulich" <JBeulich@...e.com>
To:	"John Stultz" <john.stultz@...aro.org>
Cc:	"David Vrabel" <david.vrabel@...rix.com>,
	"Jeremy Fitzhardinge" <jeremy.fitzhardinge@...rix.com>,
	"Thomas Gleixner" <tglx@...utronix.de>, <xen-devel@...ts.xen.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH 3/3] x86/xen: sync the CMOS RTC as well
 as the Xen wallclock

>>> On 14.05.13 at 17:59, John Stultz <john.stultz@...aro.org> wrote:
> On 05/14/2013 12:57 AM, Jan Beulich wrote:
>>>>> On 14.05.13 at 02:52, John Stultz <john.stultz@...aro.org> wrote:
>>> Honestly, it seems a little strange to me. If you're running as dom0,
>>> why does HYPERVISOR_dom0_op() not cause the hypervisor to set the cmos
>>> its virtualizing? This seems to mess with the proper virtualization
>>> layering.
>> Thy hypervisor tries to control as little system and peripheral devices
>> as possible, and the CMOS (including the clock) is among those not
>> controlled by it, but by Dom0.
> 
> Huh. So what does calling HYPERVISOR_dom0_op do then?

Here it merely tells the hypervisor that the wall clock changed (so
it can propagate this on to DomU-s).

Jan

--
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/