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

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Message-Id: <1406703785-10023-1-git-send-email-namit@cs.technion.ac.il>
Date:	Wed, 30 Jul 2014 10:03:05 +0300
From:	Nadav Amit <namit@...technion.ac.il>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, linux-kernel@...r.kernel.org,
	nadav.amit@...il.com, Nadav Amit <namit@...technion.ac.il>
Subject: [PATCH] KVM: x86: cluster mode broadcast does not work

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);
-- 
1.9.1

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