Re: [patch] KVM: T60 resume fix

Avi Kivity
2007-03-05T08:50:14Z

Ingo Molnar wrote:
> * Avi Kivity <avi@qumranet.com> wrote:
>
>
>>> my T60 laptop does not resume correctly due to KVM attempting to
>>> send an IPI to a CPU that might be down (or not up yet). (Doing so
>>> also triggers the send_IPI_mask_bitmask() warning in
>>> arch/i386/kernel/smp.c, line 732.)
>>>
>>> with this fix applied my laptop does not hang during resume.
>>>
>>> [ KVM will have to disable/enable virtualization on the CPU itself
>>> that goes down / comes up, not via an IPI sent from the requesting
>>> CPU. ]
>>>
>
>
>> That is already CPU_ONLINE in my tree (and in the pull request sent to
>> Linus a couple of days ago).
>>
>
> that solves the resume problem - but doesnt solve the CPU_DEAD issue of
> sending an IPI to an already offline CPU. Might be a better idea to do
> it in CPU_DOWN_PREPARE? (and then to also add a CPU_DOWN_FAILED branch?)
>
>

Mainline now has DOWN_PREPARE and UP_CANCELED calling
->hardware_disable(), and ONLINE calling ->hardware_enabled(). What
tree are you looking at?

[but I do see the need for DOWN_FAILED now. Off to find a resumable
machine...]

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.