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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Andre Przywara <andre.przywara@arm.com>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.14 249/496] KVM: arm/arm64: vgic: Add missing irq_lock to vgic_mmio_read_pending
Date:   Mon, 28 May 2018 12:00:34 +0200
Message-Id: <20180528100330.382811591@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

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

[ Upstream commit 62b06f8f429cd233e4e2e7bbd21081ad60c9018f ]

Our irq_is_pending() helper function accesses multiple members of the
vgic_irq struct, so we need to hold the lock when calling it.
Add that requirement as a comment to the definition and take the lock
around the call in vgic_mmio_read_pending(), where we were missing it
before.

Fixes: 96b298000db4 ("KVM: arm/arm64: vgic-new: Add PENDING registers handlers")
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 virt/kvm/arm/vgic/vgic-mmio.c |    3 +++
 virt/kvm/arm/vgic/vgic.h      |    1 +
 2 files changed, 4 insertions(+)

--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -110,9 +110,12 @@ unsigned long vgic_mmio_read_pending(str
 	/* Loop over all IRQs affected by this read */
 	for (i = 0; i < len * 8; i++) {
 		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+		unsigned long flags;
 
+		spin_lock_irqsave(&irq->irq_lock, flags);
 		if (irq_is_pending(irq))
 			value |= (1U << i);
+		spin_unlock_irqrestore(&irq->irq_lock, flags);
 
 		vgic_put_irq(vcpu->kvm, irq);
 	}
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -96,6 +96,7 @@
 /* we only support 64 kB translation table page size */
 #define KVM_ITS_L1E_ADDR_MASK		GENMASK_ULL(51, 16)
 
+/* Requires the irq_lock to be held by the caller. */
 static inline bool irq_is_pending(struct vgic_irq *irq)
 {
 	if (irq->config == VGIC_CONFIG_EDGE)