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From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/6] KVM: arm/arm64: vgic-v2: Limit ITARGETSR bits to number of VCPUs
Date: Fri,  9 Dec 2016 15:53:29 +0000	[thread overview]
Message-ID: <1481298811-30798-5-git-send-email-marc.zyngier@arm.com> (raw)
In-Reply-To: <1481298811-30798-1-git-send-email-marc.zyngier@arm.com>

From: Andre Przywara <andre.przywara@arm.com>

The GICv2 spec says in section 4.3.12 that a "CPU targets field bit that
corresponds to an unimplemented CPU interface is RAZ/WI."
Currently we allow the guest to write any value in there and it can
read that back.
Mask the written value with the proper CPU mask to be spec compliant.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 virt/kvm/arm/vgic/vgic-mmio-v2.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index b44b359..78e34bc 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -129,6 +129,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
 				   unsigned long val)
 {
 	u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
+	u8 cpu_mask = GENMASK(atomic_read(&vcpu->kvm->online_vcpus) - 1, 0);
 	int i;
 
 	/* GICD_ITARGETSR[0-7] are read-only */
@@ -141,7 +142,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
 
 		spin_lock(&irq->irq_lock);
 
-		irq->targets = (val >> (i * 8)) & 0xff;
+		irq->targets = (val >> (i * 8)) & cpu_mask;
 		target = irq->targets ? __ffs(irq->targets) : 0;
 		irq->target_vcpu = kvm_get_vcpu(vcpu->kvm, target);
 
-- 
2.1.4

  parent reply	other threads:[~2016-12-09 15:53 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-09 15:53 [PULL] KVM/ARM updates for 4.10 Marc Zyngier
2016-12-09 15:53 ` [PATCH 1/6] KVM: arm64: vgic-its: Fix compatibility with 32-bit Marc Zyngier
2016-12-09 15:53 ` [PATCH 2/6] ARM: KVM: Support vGICv3 ITS Marc Zyngier
2016-12-09 15:53 ` [PATCH 3/6] arm/arm64: KVM: Clean up useless code in kvm_timer_enable Marc Zyngier
2016-12-09 15:53 ` Marc Zyngier [this message]
2016-12-09 15:53 ` [PATCH 5/6] KVM: arm/arm64: timer: Check for properly initialized timer on init Marc Zyngier
2016-12-09 15:53 ` [PATCH 6/6] arm64: KVM: pmu: Reset PMSELR_EL0.SEL to a sane value before entering the guest Marc Zyngier

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