[PATCH v3a] KVM: arm/arm64: pmu: abstract access to number of SPIs

[Andre Przywara]

Currently the PMU uses a member of the struct vgic_dist directly,
which not only breaks abstraction, but will fail with the new VGIC.
Abstract this access in the VGIC header file.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
Hi Eric, Marc,

as this if-statement was quite confusing (it wasn't even the negation
that was wrong), I rewrote it a bit to be more readable.
This one works now with PPIs (after fixing kvmtool).

Does that make sense?

Cheers,
Andre.

 include/kvm/arm_vgic.h |  2 ++
 virt/kvm/arm/pmu.c     | 19 +++++++++++--------
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 6a98e05..d406f8e 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -351,6 +351,8 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq);
 #define irqchip_in_kernel(k)	(!!((k)->arch.vgic.in_kernel))
 #define vgic_initialized(k)	(!!((k)->arch.vgic.nr_cpus))
 #define vgic_ready(k)		((k)->arch.vgic.ready)
+#define vgic_valid_spi(k, i)	(((i) >= VGIC_NR_PRIVATE_IRQS) && \
+				 ((i) < (k)->arch.vgic.nr_irqs))
 
 int vgic_v2_probe(struct device_node *vgic_node,
 		  const struct vgic_ops **ops,
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 575c7aa..6ab9d6b 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -436,6 +436,11 @@ static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
+/*
+ * For one VM the interrupt type must be same for each vcpu.
+ * As a PPI, the interrupt number is the same for all vcpus,
+ * while as an SPI it must be a separate number per vcpu.
+ */
 static bool irq_is_valid(struct kvm *kvm, int irq, bool is_ppi)
 {
 	int i;
@@ -457,6 +462,7 @@ static bool irq_is_valid(struct kvm *kvm, int irq, bool is_ppi)
 	return true;
 }
 
+#define irq_is_ppi(irq) ((irq) >= VGIC_NR_SGIS && (irq) < VGIC_NR_PRIVATE_IRQS)
 
 int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 {
@@ -471,14 +477,11 @@ int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 		if (get_user(irq, uaddr))
 			return -EFAULT;
 
-		/*
-		 * The PMU overflow interrupt could be a PPI or SPI, but for one
-		 * VM the interrupt type must be same for each vcpu. As a PPI,
-		 * the interrupt number is the same for all vcpus, while as an
-		 * SPI it must be a separate number per vcpu.
-		 */
-		if (irq < VGIC_NR_SGIS || irq >= vcpu->kvm->arch.vgic.nr_irqs ||
-		    !irq_is_valid(vcpu->kvm, irq, irq < VGIC_NR_PRIVATE_IRQS))
+		/* The PMU overflow interrupt can be a PPI or a valid SPI. */
+		if (!(irq_is_ppi(irq) || vgic_valid_spi(vcpu->kvm, irq)))
+			return -EINVAL;
+
+		if (!irq_is_valid(vcpu->kvm, irq, irq < VGIC_NR_PRIVATE_IRQS))
 			return -EINVAL;
 
 		if (kvm_arm_pmu_irq_initialized(vcpu))
-- 
2.7.3