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KVM: arm/arm64: vgic: Prevent userspace injection of a mapped interrupt

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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 <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier 2015-07-24 11:30:43 +01:00
parent 6e84e0e067
commit 773299a570
2 changed files with 73 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
include/kvm/arm_vgic.h
View file

@ -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);

105
virt/kvm/arm/vgic.c
View file

@ -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);
@ -1625,28 +1629,17 @@ 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;
}
/**
* 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
* @level: Edge-triggered: true: to trigger the interrupt
* false: to ignore the call
* Level-sensitive true: activates an interrupt
* false: deactivates an interrupt
*
* 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_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
bool level)
static int vgic_lazy_init(struct kvm *kvm)
{
int ret = 0;
int vcpu_id;
if (unlikely(!vgic_initialized(kvm))) {
/*
@ -1655,29 +1648,73 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
* 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;
}
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);
if (ret)
goto out;
}
if (irq_num >= min(kvm->arch.vgic.nr_irqs, 1020))
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. 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: 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_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
bool level)
{
struct irq_phys_map *map;
int ret;
ret = vgic_lazy_init(kvm);
if (ret)
return ret;
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)