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Date: Wed, 13 Jul 2016 16:52:49 +0200
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        "Lan, Tianyu" <tianyu.lan@intel.com>,
        Igor Mammedov <imammedo@redhat.com>, Jan Kiszka <jan.kiszka@web.de>,
        Peter Xu <peterx@redhat.com>, Yang Zhang <yang.zhang.wz@gmail.com>
Subject: Re: [PATCH v3 12/14] KVM: x86: add a flag to disable KVM x2apic
 broadcast quirk
Message-ID: <20160713145249.GC22438@potion>
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 <20160712200930.32143-13-rkrcmar@redhat.com>
 <10fcb396-853f-e08b-48d9-c2e69189798d@redhat.com>
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2016-07-13 12:15+0200, Paolo Bonzini:
> On 12/07/2016 22:09, Radim Krčmář wrote:
>> +static bool kvm_apic_map_need_slowpath(struct kvm *kvm, struct kvm_lapic **src,
>> +		struct kvm_lapic_irq *irq, struct kvm_apic_map *map)
>> +{
>> +	if (!map)
>> +		return true;
>> +
>> +	if (kvm->arch.x2apic_broadcast_quirk_disabled) {
>> +		if ((irq->dest_id == APIC_BROADCAST &&
>> +				map->mode != KVM_APIC_MODE_X2APIC))
>> +			return true;
>> +		if (irq->dest_id == X2APIC_BROADCAST)
>> +			return true;
>> +	} else {
>> +		bool x2apic_ipi = src && *src && apic_x2apic_mode(*src);
>> +		if (irq->dest_id == (x2apic_ipi ?
>> +		                     X2APIC_BROADCAST : APIC_BROADCAST))
>> +			return true;
>> +	}
>> +
>> +	return false;
>> +}
> 
> This isn't the only case where you go through the slowpath.  What about
> renaming to kvm_apic_dest_is_broadcast?

Yeah, sorry.  I have a patch that adds a check for 0xff in flat lapic
mode (can be handled in the fast path) and used the same name even
before the check ...