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

From: Avi Kivity
Date: Mon Aug 25 2008 - 09:35:59 EST


Eric W. Biederman wrote:
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?


We need to do it across all cpus.

However, a reliable (and simpler) fix has emerged: reset via ACPI. That causes a true reset which VT does not block.


--
error compiling committee.c: too many arguments to function

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