linux-kernel - [PATCH 4/8] KVM: x86: fix x2apic logical address matching

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Date:	Thu, 29 Jan 2015 22:48:51 +0100
From:	Radim Krčmář <rkrcmar@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
	Nadav Amit <namit@...technion.ac.il>,
	Gleb Natapov <gleb@...nel.org>
Subject: [PATCH 4/8] KVM: x86: fix x2apic logical address matching

We cannot hit the bug now, but future patches will expose this path.

Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
---
 arch/x86/kvm/lapic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0ee743c6b4f1..aae043f38548 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -602,7 +602,8 @@ static bool kvm_apic_match_logical_addr(struct kvm_lapic *apic, u32 mda)
 	logical_id = kvm_apic_get_reg(apic, APIC_LDR);
 
 	if (apic_x2apic_mode(apic))
-		return logical_id & mda;
+		return ((logical_id >> 16) == (mda >> 16))
+		       && (logical_id & mda & 0xffff);
 
 	logical_id = GET_APIC_LOGICAL_ID(logical_id);
 
-- 
2.2.2

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