Re: [GIT PULL] x86/apic updates for v3.20

[Jiang Liu]

On 2015/2/14 1:00, Linus Torvalds wrote:
> On Fri, Feb 13, 2015 at 7:47 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote:
>>
>> So the condition should rather look like this to keep x2apic disabled
>> like before:
> 
> Yes, this works for me too.
> 
>> diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
>> index b665d24..770a0bb 100644
>> --- a/arch/x86/kernel/apic/apic.c
>> +++ b/arch/x86/kernel/apic/apic.c
>> @@ -1580,8 +1580,8 @@ static __init void try_to_enable_x2apic(int remap_mode)
>>                  * under KVM
>>                  */
>>                 if (max_physical_apicid > 255 ||
>> -                   (IS_ENABLED(CONFIG_HYPERVISOR_GUEST) &&
>> -                    !hypervisor_x2apic_available())) {
>> +                   !(IS_ENABLED(CONFIG_HYPERVISOR_GUEST) &&
>> +                     hypervisor_x2apic_available())) {
>>                         pr_info("x2apic: IRQ remapping doesn't support X2APIC mode\n");
>>                         x2apic_disable();
>>                         return;
>>
>> Another solution would be to just revert 5fcee53ce705. This code is not
>> in any fast-path, so we can live well without that optimization.
> 
> Jiang, preferences? Revert, or fix like the above?
Hi Linus,
	I think reverting is better.
	The IS_ENABLED(CONFIG_HYPERVISOR_GUEST) optimization doesn't
give us much, but it makes the code a little complex.
Regards!
Gerry

> 
>                      Linus
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