linux-kernel - Re: [PATCH] KVM: x86: cluster mode broadcast does not work

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Message-ID: <53DA80ED.70003@gmail.com>
Date:	Thu, 31 Jul 2014 20:46:21 +0300
From:	Nadav Amit <nadav.amit@...il.com>
To:	Nadav Amit <namit@...technion.ac.il>, pbonzini@...hat.com
CC:	gleb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Subject: Re: [PATCH] KVM: x86: cluster mode broadcast does not work

cc'ing the kvm mailing list that was mistakenly omitted.

On 7/30/14 10:03 AM, Nadav Amit wrote:
> Local-apic enables cluster mode broadcast. As Intel SDM 10.6.2.2 says:
> "Broadcast to all local APICs is achieved by setting all destination bits to
> one." This patch enables cluster mode broadcast.
> 
> Signed-off-by: Nadav Amit <namit@...technion.ac.il>
> ---
>  arch/x86/kvm/lapic.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index efb1939..05c9a46 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -560,8 +560,8 @@ int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
>  			result = 1;
>  		break;
>  	case APIC_DFR_CLUSTER:
> -		if (((logical_id >> 4) == (mda >> 0x4))
> -		    && (logical_id & mda & 0xf))
> +		if ((((logical_id >> 4) == (mda >> 0x4))
> +		    && (logical_id & mda & 0xf)) || mda == 0xff)
>  			result = 1;
>  		break;
>  	default:
> @@ -644,6 +644,10 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
>  	} else {
>  		u32 mda = irq->dest_id << (32 - map->ldr_bits);
>  
> +		if (irq->dest_id == 0xff &&
> +		    kvm_apic_get_reg(src, APIC_DFR) == APIC_DFR_CLUSTER)
> +			goto out; /* cluster mode broadcast */
> +
>  		dst = map->logical_map[apic_cluster_id(map, mda)];
>  
>  		bitmap = apic_logical_id(map, mda);
> 
--
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