Subject: Re: [patch] KVM: T60 resume fix

From: Avi Kivity <[email-masked]>
Date: Sat, 03 Mar 2007 10:21:38 +0200

Ingo Molnar wrote:
> Subject: [patch] KVM: T60 resume fix
> From: Ingo Molnar <[email-masked]>
>
> 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. ]
>
> Signed-off-by: Ingo Molnar <[email-masked]>
> ---
>  drivers/kvm/kvm_main.c |    6 ------
>  1 file changed, 6 deletions(-)
>
> Index: linux/drivers/kvm/kvm_main.c
> ===================================================================
> --- linux.orig/drivers/kvm/kvm_main.c
> +++ linux/drivers/kvm/kvm_main.c
> @@ -2083,12 +2083,6 @@ static int kvm_cpu_hotplug(struct notifi
>  	case CPU_DEAD:
>  	case CPU_UP_CANCELED:
>  		decache_vcpus_on_cpu(cpu);
> -		smp_call_function_single(cpu, kvm_arch_ops->hardware_disable,
> -					 NULL, 0, 1);
> -		break;
> -	case CPU_UP_PREPARE:
> -		smp_call_function_single(cpu, kvm_arch_ops->hardware_enable,
> -					 NULL, 0, 1);
>  		break;
>  	}
>  	return NOTIFY_OK;
>   

That is already CPU_ONLINE in my tree (and in the pull request sent to 
Linus a couple of days ago).

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