linux-kernel - Re: [RFC PATCH 0/2] kvm/vmx: Output TSC offset

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]

Message-ID: <CAJL_ekvb89saY9F0F3ip-8xipuuRyJ1_M8hOyThu_0Q2=5sXgA@mail.gmail.com>
Date:	Tue, 13 Nov 2012 18:03:03 -0800
From:	David Sharp <dhsharp@...gle.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>,
	linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
	kvm@...r.kernel.org, Joerg Roedel <joerg.roedel@....com>,
	Marcelo Tosatti <mtosatti@...hat.com>,
	Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>,
	Ingo Molnar <mingo@...hat.com>, Avi Kivity <avi@...hat.com>,
	yrl.pp-manager.tt@...achi.com,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RFC PATCH 0/2] kvm/vmx: Output TSC offset

On Tue, Nov 13, 2012 at 6:00 PM, Steven Rostedt <rostedt@...dmis.org> wrote:
> On Wed, 2012-11-14 at 10:36 +0900, Yoshihiro YUNOMAE wrote:
>
>> To merge the data like previous pattern, we apply this patch set. Then, we can
>> get TSC offset of the guest as follows:
>>
>> $ dmesg | grep kvm
>> [   57.717180] kvm: (2687) write TSC offset 18446743360465545001, now clock ##
>>                      ^^^^                   ^^^^^^^^^^^^^^^^^^^^            |
>>                      PID                         TSC offset                 |
>>                                                            HOST TSC value --+
>>
>
> Using printk to export something like this is IMO a nasty hack.
>
> Can't we create a /sys or /proc file to export the same thing?

Since the value changes over the course of the trace, and seems to be
part of the context of the trace, I think I'd include it as a
tracepoint.

>
> -- Steve
>
>
--
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/