4.20-stable review patch. If anyone has any objections, please let me know.
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From: Christoffer Dall christoffer.dall@arm.com
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
--- virt/kvm/arm/vgic/vgic-mmio.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
--- 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(stru 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)