[PATCH v6 10/13] ARM: KVM: VGIC interrupt injection

Christoffer Dall
2013-01-16T18:01:25Z

Plug the interrupt injection code. Interrupts can now be generated
from user space.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
arch/arm/include/asm/kvm_vgic.h | 8 +++
arch/arm/kvm/arm.c | 55 +++++++++++++++---
arch/arm/kvm/vgic.c | 117 +++++++++++++++++++++++++++++++++++++++
3 files changed, 170 insertions(+), 10 deletions(-)

diff --git a/arch/arm/include/asm/kvm_vgic.h b/arch/arm/include/asm/kvm_vgic.h
index 1081649..8aea9df 100644
--- a/arch/arm/include/asm/kvm_vgic.h
+++ b/arch/arm/include/asm/kvm_vgic.h
@@ -147,6 +147,8 @@ struct kvm_exit_mmio;
int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr);
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_vcpu_pending_irq(struct kvm_vcpu *vcpu);
bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
struct kvm_exit_mmio *mmio);
@@ -182,6 +184,12 @@ static inline int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
static inline void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu) {}
static inline void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu) {}

+static inline int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid,
+ unsigned int irq_num, bool level)
+{
+ return 0;
+}
+
static inline int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
{
return 0;
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 6e60fd8..a0e93d3 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -805,20 +805,49 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level)

trace_kvm_irq_line(irq_type, vcpu_idx, irq_num, irq_level->level);

- if (irq_type != KVM_ARM_IRQ_TYPE_CPU)
- return -EINVAL;
+ switch (irq_type) {
+ case KVM_ARM_IRQ_TYPE_CPU:
+ if (irqchip_in_kernel(kvm))
+ return -ENXIO;

- if (vcpu_idx >= nrcpus)
- return -EINVAL;
+ if (vcpu_idx >= nrcpus)
+ return -EINVAL;

- vcpu = kvm_get_vcpu(kvm, vcpu_idx);
- if (!vcpu)
- return -EINVAL;
+ vcpu = kvm_get_vcpu(kvm, vcpu_idx);
+ if (!vcpu)
+ return -EINVAL;

- if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
- return -EINVAL;
+ if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
+ return -EINVAL;
+
+ return vcpu_interrupt_line(vcpu, irq_num, level);
+ case KVM_ARM_IRQ_TYPE_PPI:
+ if (!irqchip_in_kernel(kvm))
+ return -ENXIO;
+
+ if (vcpu_idx >= nrcpus)
+ return -EINVAL;
+
+ vcpu = kvm_get_vcpu(kvm, vcpu_idx);
+ if (!vcpu)
+ return -EINVAL;
+
+ if (irq_num < VGIC_NR_SGIS || irq_num >= VGIC_NR_PRIVATE_IRQS)
+ return -EINVAL;

- return vcpu_interrupt_line(vcpu, irq_num, level);
+ return kvm_vgic_inject_irq(kvm, vcpu->vcpu_id, irq_num, level);
+ case KVM_ARM_IRQ_TYPE_SPI:
+ if (!irqchip_in_kernel(kvm))
+ return -ENXIO;
+
+ if (irq_num < VGIC_NR_PRIVATE_IRQS ||
+ irq_num > KVM_ARM_IRQ_GIC_MAX)
+ return -EINVAL;
+
+ return kvm_vgic_inject_irq(kvm, 0, irq_num, level);
+ }
+
+ return -EINVAL;
}

long kvm_arch_vcpu_ioctl(struct file *filp,
@@ -897,6 +926,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
void __user *argp = (void __user *)arg;

switch (ioctl) {
+ case KVM_CREATE_IRQCHIP: {
+ if (vgic_present)
+ return kvm_vgic_create(kvm);
+ else
+ return -ENXIO;
+ }
case KVM_ARM_SET_DEVICE_ADDR: {
struct kvm_arm_device_addr dev_addr;

diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
index 2d5e29f..2e6a585 100644
--- a/arch/arm/kvm/vgic.c
+++ b/arch/arm/kvm/vgic.c
@@ -73,6 +73,7 @@

static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
static void vgic_update_state(struct kvm *kvm);
+static void vgic_kick_vcpus(struct kvm *kvm);
static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);

static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x,
@@ -708,6 +709,9 @@ bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
kvm_prepare_mmio(run, mmio);
kvm_handle_mmio_return(vcpu, run);

+ if (updated_state)
+ vgic_kick_vcpus(vcpu->kvm);
+
return true;
}

@@ -1104,6 +1108,119 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
return test_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
}

+static void vgic_kick_vcpus(struct kvm *kvm)
+{
+ struct kvm_vcpu *vcpu;
+ int c;
+
+ /*
+ * We've injected an interrupt, time to find out who deserves
+ * a good kick...
+ */
+ kvm_for_each_vcpu(c, vcpu, kvm) {
+ if (kvm_vgic_vcpu_pending_irq(vcpu))
+ kvm_vcpu_kick(vcpu);
+ }
+}
+
+static int vgic_validate_injection(struct kvm_vcpu *vcpu, int irq, int level)
+{
+ int is_edge = vgic_irq_is_edge(vcpu, irq);
+ int state = vgic_dist_irq_is_pending(vcpu, irq);
+
+ /*
+ * Only inject an interrupt if:
+ * - edge triggered and we have a rising edge
+ * - level triggered and we change level
+ */
+ if (is_edge)
+ return level > state;
+ else
+ return level != state;
+}
+
+static bool vgic_update_irq_state(struct kvm *kvm, int cpuid,
+ unsigned int irq_num, bool level)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct kvm_vcpu *vcpu;
+ int is_edge, is_level;
+ int enabled;
+ bool ret = true;
+
+ spin_lock(&dist->lock);
+
+ vcpu = kvm_get_vcpu(kvm, cpuid);
+ is_edge = vgic_irq_is_edge(vcpu, irq_num);
+ is_level = !is_edge;
+
+ if (!vgic_validate_injection(vcpu, irq_num, level)) {
+ ret = false;
+ goto out;
+ }
+
+ if (irq_num >= VGIC_NR_PRIVATE_IRQS) {
+ cpuid = dist->irq_spi_cpu[irq_num - VGIC_NR_PRIVATE_IRQS];
+ vcpu = kvm_get_vcpu(kvm, cpuid);
+ }
+
+ kvm_debug("Inject IRQ%d level %d CPU%d\n", irq_num, level, cpuid);
+
+ if (level)
+ vgic_dist_irq_set(vcpu, irq_num);
+ else
+ vgic_dist_irq_clear(vcpu, irq_num);
+
+ enabled = vgic_irq_is_enabled(vcpu, irq_num);
+
+ if (!enabled) {
+ ret = false;
+ goto out;
+ }
+
+ if (is_level && vgic_irq_is_active(vcpu, irq_num)) {
+ /*
+ * Level interrupt in progress, will be picked up
+ * when EOId.
+ */
+ ret = false;
+ goto out;
+ }
+
+ if (level) {
+ vgic_cpu_irq_set(vcpu, irq_num);
+ set_bit(cpuid, &dist->irq_pending_on_cpu);
+ }
+
+out:
+ spin_unlock(&dist->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
+ * @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)
+{
+ if (vgic_update_irq_state(kvm, cpuid, irq_num, level))
+ vgic_kick_vcpus(kvm);
+
+ return 0;
+}
+
static bool vgic_ioaddr_overlap(struct kvm *kvm)
{
phys_addr_t dist = kvm->arch.vgic.vgic_dist_base;