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authorChristoffer Dall <christoffer.dall@arm.com>2018-12-11 12:51:03 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-09 17:38:49 +0100
commit47ffaa7decc5ed224efe1da57e6d98fa451a8058 (patch)
tree551c1123ce504b9e975263da5fd260f264da241d /virt
parent6318b1b7c90cf60e2a64918734201edcc0e22b3e (diff)
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KVM: arm/arm64: vgic-v2: Set active_source to 0 when restoring state
commit 60c3ab30d8c2ff3a52606df03f05af2aae07dc6b upstream. When restoring the active state from userspace, we don't know which CPU was the source for the active state, and this is not architecturally exposed in any of the register state. Set the active_source to 0 in this case. In the future, we can expand on this and exposse the information as additional information to userspace for GICv2 if anyone cares. Cc: stable@vger.kernel.org Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/arm/vgic/vgic-mmio.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 46148fcf0838..ceeda7e04a4d 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -317,11 +317,26 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
vgic_hw_irq_change_active(vcpu, irq, active, !requester_vcpu);
} else {
u32 model = vcpu->kvm->arch.vgic.vgic_model;
+ u8 active_source;
irq->active = active;
+
+ /*
+ * The GICv2 architecture indicates that the source CPUID for
+ * an SGI should be provided during an EOI which implies that
+ * the active state is stored somewhere, but at the same time
+ * this state is not architecturally exposed anywhere and we
+ * have no way of knowing the right source.
+ *
+ * This may lead to a VCPU not being able to receive
+ * additional instances of a particular SGI after migration
+ * for a GICv2 VM on some GIC implementations. Oh well.
+ */
+ active_source = (requester_vcpu) ? requester_vcpu->vcpu_id : 0;
+
if (model == KVM_DEV_TYPE_ARM_VGIC_V2 &&
active && vgic_irq_is_sgi(irq->intid))
- irq->active_source = requester_vcpu->vcpu_id;
+ irq->active_source = active_source;
}
if (irq->active)