Re: [patch] KVM: T60 resume fix

[Avi Kivity]

Ingo Molnar wrote:
> * Avi Kivity <avi@xxxxxxxxxxxx> 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.

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