linux-kernel - [PATCH 4.9 81/83] KVM: arm/arm64: vgic-v2: Handle SGI bits in GICD

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Message-Id: <20190904175310.767573981@linuxfoundation.org>
Date:   Wed,  4 Sep 2019 19:54:13 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Andre Przywara <andre.przywara@....com>,
        Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 81/83] KVM: arm/arm64: vgic-v2: Handle SGI bits in GICD_I{S,C}PENDR0 as WI

[ Upstream commit 82e40f558de566fdee214bec68096bbd5e64a6a4 ]

A guest is not allowed to inject a SGI (or clear its pending state)
by writing to GICD_ISPENDR0 (resp. GICD_ICPENDR0), as these bits are
defined as WI (as per ARM IHI 0048B 4.3.7 and 4.3.8).

Make sure we correctly emulate the architecture.

Fixes: 96b298000db4 ("KVM: arm/arm64: vgic-new: Add PENDING registers handlers")
Cc: stable@...r.kernel.org # 4.7+
Reported-by: Andre Przywara <andre.przywara@....com>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Signed-off-by: Will Deacon <will@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 virt/kvm/arm/vgic/vgic-mmio.c | 18 ++++++++++++++++++
 virt/kvm/arm/vgic/vgic-v2.c   |  5 ++++-
 virt/kvm/arm/vgic/vgic-v3.c   |  5 ++++-
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 85814d1bad11e..87742c9803a75 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -120,6 +120,12 @@ unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
 	return value;
 }
 
+static bool is_vgic_v2_sgi(struct kvm_vcpu *vcpu, struct vgic_irq *irq)
+{
+	return (vgic_irq_is_sgi(irq->intid) &&
+		vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2);
+}
+
 void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
 			      gpa_t addr, unsigned int len,
 			      unsigned long val)
@@ -130,6 +136,12 @@ void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
 	for_each_set_bit(i, &val, len * 8) {
 		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
 
+		/* GICD_ISPENDR0 SGI bits are WI */
+		if (is_vgic_v2_sgi(vcpu, irq)) {
+			vgic_put_irq(vcpu->kvm, irq);
+			continue;
+		}
+
 		spin_lock(&irq->irq_lock);
 		irq->pending = true;
 		if (irq->config == VGIC_CONFIG_LEVEL)
@@ -150,6 +162,12 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
 	for_each_set_bit(i, &val, len * 8) {
 		struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
 
+		/* GICD_ICPENDR0 SGI bits are WI */
+		if (is_vgic_v2_sgi(vcpu, irq)) {
+			vgic_put_irq(vcpu->kvm, irq);
+			continue;
+		}
+
 		spin_lock(&irq->irq_lock);
 
 		if (irq->config == VGIC_CONFIG_LEVEL) {
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 1ab58f7b5d749..4c2919cc13ca6 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -154,7 +154,10 @@ void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
 		if (vgic_irq_is_sgi(irq->intid)) {
 			u32 src = ffs(irq->source);
 
-			BUG_ON(!src);
+			if (WARN_RATELIMIT(!src, "No SGI source for INTID %d\n",
+					   irq->intid))
+				return;
+
 			val |= (src - 1) << GICH_LR_PHYSID_CPUID_SHIFT;
 			irq->source &= ~(1 << (src - 1));
 			if (irq->source)
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index c7924718990e5..267b1cf88a7fe 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -137,7 +137,10 @@ void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
 		    model == KVM_DEV_TYPE_ARM_VGIC_V2) {
 			u32 src = ffs(irq->source);
 
-			BUG_ON(!src);
+			if (WARN_RATELIMIT(!src, "No SGI source for INTID %d\n",
+					   irq->intid))
+				return;
+
 			val |= (src - 1) << GICH_LR_PHYSID_CPUID_SHIFT;
 			irq->source &= ~(1 << (src - 1));
 			if (irq->source)
-- 
2.20.1