Re: [PATCH] KVM: VMX: Fix repeatlycalling alloc_apic_access_page()

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Dong, Eddie wrote:
>>> -	if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm))
>>> +	if ((vmx->vcpu.vcpu_id == 0) &&
>>> +	    (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)))
>>>  		if (alloc_apic_access_page(vmx->vcpu.kvm) != 0)
>>>  			return -ENOMEM;
>>>
>>>
>>>       
>> We may not have vcpu id 0 (though it's very unlikely).
>>
>>     
>
> Current LAPIC code assume vcpu_id = 0 for BSP.
> And even no real support of APIC_ID change.
>
> How about use  (vcpu->apic_base & MSR_IA32_APICBASE_BSP) ?
>   

Taking kvm->mutex and checking avoids hidden dependencies and is 
necessary anyway.

I need to sit down and document the kvm locking rules.

-- 
Any sufficiently difficult bug is indistinguishable from a feature.


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >> http://get.splunk.com/