From 773299a570725d1f253d6046cd6475209b0dcd55 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 24 Jul 2015 11:30:43 +0100 Subject: [PATCH] KVM: arm/arm64: vgic: Prevent userspace injection of a mapped interrupt Virtual interrupts mapped to a HW interrupt should only be triggered from inside the kernel. Otherwise, you could end up confusing the kernel (and the GIC's) state machine. Rearrange the injection path so that kvm_vgic_inject_irq is used for non-mapped interrupts, and kvm_vgic_inject_mapped_irq is used for mapped interrupts. The latter should only be called from inside the kernel (timer, irqfd). Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- include/kvm/arm_vgic.h | 2 + virt/kvm/arm/vgic.c | 103 ++++++++++++++++++++++++++++------------- 2 files changed, 72 insertions(+), 33 deletions(-) diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index e789e4721139..d901f1a47be6 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -350,6 +350,8 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu); void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu); int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level); +int kvm_vgic_inject_mapped_irq(struct kvm *kvm, int cpuid, + struct irq_phys_map *map, bool level); void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg); int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu); int kvm_vgic_vcpu_active_irq(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index b553a8fa6430..9eb489a2c94c 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1555,7 +1555,8 @@ static int vgic_validate_injection(struct kvm_vcpu *vcpu, int irq, int level) } static int vgic_update_irq_pending(struct kvm *kvm, int cpuid, - unsigned int irq_num, bool level) + struct irq_phys_map *map, + unsigned int irq_num, bool level) { struct vgic_dist *dist = &kvm->arch.vgic; struct kvm_vcpu *vcpu; @@ -1563,6 +1564,9 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid, int enabled; bool ret = true, can_inject = true; + if (irq_num >= min(kvm->arch.vgic.nr_irqs, 1020)) + return -EINVAL; + spin_lock(&dist->lock); vcpu = kvm_get_vcpu(kvm, cpuid); @@ -1625,18 +1629,46 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid, out: spin_unlock(&dist->lock); - return ret ? cpuid : -EINVAL; + if (ret) { + /* kick the specified vcpu */ + kvm_vcpu_kick(kvm_get_vcpu(kvm, cpuid)); + } + + return 0; +} + +static int vgic_lazy_init(struct kvm *kvm) +{ + int ret = 0; + + if (unlikely(!vgic_initialized(kvm))) { + /* + * We only provide the automatic initialization of the VGIC + * for the legacy case of a GICv2. Any other type must + * be explicitly initialized once setup with the respective + * KVM device call. + */ + if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2) + return -EBUSY; + + mutex_lock(&kvm->lock); + ret = vgic_init(kvm); + mutex_unlock(&kvm->lock); + } + + return ret; } /** * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic * @kvm: The VM structure pointer * @cpuid: The CPU for PPIs - * @irq_num: The IRQ number that is assigned to the device + * @irq_num: The IRQ number that is assigned to the device. This IRQ + * must not be mapped to a HW interrupt. * @level: Edge-triggered: true: to trigger the interrupt * false: to ignore the call - * Level-sensitive true: activates an interrupt - * false: deactivates an interrupt + * Level-sensitive true: raise the input signal + * false: lower the input signal * * The GIC is not concerned with devices being active-LOW or active-HIGH for * level-sensitive interrupts. You can think of the level parameter as 1 @@ -1645,39 +1677,44 @@ out: int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level) { - int ret = 0; - int vcpu_id; - - if (unlikely(!vgic_initialized(kvm))) { - /* - * We only provide the automatic initialization of the VGIC - * for the legacy case of a GICv2. Any other type must - * be explicitly initialized once setup with the respective - * KVM device call. - */ - if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2) { - ret = -EBUSY; - goto out; - } - mutex_lock(&kvm->lock); - ret = vgic_init(kvm); - mutex_unlock(&kvm->lock); + struct irq_phys_map *map; + int ret; - if (ret) - goto out; - } + ret = vgic_lazy_init(kvm); + if (ret) + return ret; - if (irq_num >= min(kvm->arch.vgic.nr_irqs, 1020)) + map = vgic_irq_map_search(kvm_get_vcpu(kvm, cpuid), irq_num); + if (map) return -EINVAL; - vcpu_id = vgic_update_irq_pending(kvm, cpuid, irq_num, level); - if (vcpu_id >= 0) { - /* kick the specified vcpu */ - kvm_vcpu_kick(kvm_get_vcpu(kvm, vcpu_id)); - } + return vgic_update_irq_pending(kvm, cpuid, NULL, irq_num, level); +} -out: - return ret; +/** + * kvm_vgic_inject_mapped_irq - Inject a physically mapped IRQ to the vgic + * @kvm: The VM structure pointer + * @cpuid: The CPU for PPIs + * @map: Pointer to a irq_phys_map structure describing the mapping + * @level: Edge-triggered: true: to trigger the interrupt + * false: to ignore the call + * Level-sensitive true: raise the input signal + * false: lower the input signal + * + * The GIC is not concerned with devices being active-LOW or active-HIGH for + * level-sensitive interrupts. You can think of the level parameter as 1 + * being HIGH and 0 being LOW and all devices being active-HIGH. + */ +int kvm_vgic_inject_mapped_irq(struct kvm *kvm, int cpuid, + struct irq_phys_map *map, bool level) +{ + int ret; + + ret = vgic_lazy_init(kvm); + if (ret) + return ret; + + return vgic_update_irq_pending(kvm, cpuid, map, map->virt_irq, level); } static irqreturn_t vgic_maintenance_handler(int irq, void *data) -- 2.20.1