linux-kernel - Re: [PATCH] Fix emergency_restart (sysrq-b) with kvm loaded on Intel hosts

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: <m1y72lnsqj.fsf@frodo.ebiederm.org>
Date:	Mon, 25 Aug 2008 06:12:36 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Avi Kivity <avi@...ranet.com>, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Subject: Re: [PATCH] Fix emergency_restart (sysrq-b) with kvm loaded on Intel hosts

Ingo Molnar <mingo@...e.hu> writes:

> * Avi Kivity <avi@...ranet.com> wrote:
>
>> Enabling Intel VT has the curious side effect whereby the INIT signal 
>> is blocked.  Rather than comment on the wisdom of this side effect, 
>> this patch adds an emergency restart reboot notifier, and modifies the 
>> kvm reboot notifier to disable VT on emergency reboot.

Please no notifiers in emergency_restart.

First emergency_restart is not supposed to work reliably it is a best effort tickle
the hardware thing.

Second and more importantly whenever someone adds a notifier instead of a proper hook
to one a code path like this it seems like avoiding building a proper interface so
and I believe keeps us from getting all of the logic and the heuristics right.

Why not just add a disable intel_vt if it is enabled call?

Eric
--
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/