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

From: Eric W. Biederman
Date: Mon Aug 25 2008 - 09:24:21 EST


Ingo Molnar <mingo@xxxxxxx> writes:

> * Avi Kivity <avi@xxxxxxxxxxxx> 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
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