KVM: ARM: Inject IRQs and FIQs from userspace
All interrupt injection is now based on the VM ioctl KVM_IRQ_LINE. This
works semantically well for the GIC as we in fact raise/lower a line on
a machine component (the gic). The IOCTL uses the follwing struct.
struct kvm_irq_level {
union {
__u32 irq; /* GSI */
__s32 status; /* not used for KVM_IRQ_LEVEL */
};
__u32 level; /* 0 or 1 */
};
ARM can signal an interrupt either at the CPU level, or at the in-kernel irqchip
(GIC), and for in-kernel irqchip can tell the GIC to use PPIs designated for
specific cpus. The irq field is interpreted like this:
bits: | 31 ... 24 | 23 ... 16 | 15 ... 0 |
field: | irq_type | vcpu_index | irq_number |
The irq_type field has the following values:
- irq_type[0]: out-of-kernel GIC: irq_number 0 is IRQ, irq_number 1 is FIQ
- irq_type[1]: in-kernel GIC: SPI, irq_number between 32 and 1019 (incl.)
(the vcpu_index field is ignored)
- irq_type[2]: in-kernel GIC: PPI, irq_number between 16 and 31 (incl.)
The irq_number thus corresponds to the irq ID in as in the GICv2 specs.
This is documented in Documentation/kvm/api.txt.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index d810afb..2101152 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -24,6 +24,7 @@
#include <linux/fs.h>
#include <linux/mman.h>
#include <linux/sched.h>
+#include <linux/kvm.h>
#include <trace/events/kvm.h>
#define CREATE_TRACE_POINTS
@@ -284,6 +285,7 @@
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
+ vcpu->cpu = cpu;
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
@@ -319,6 +321,69 @@
return -EINVAL;
}
+static int vcpu_interrupt_line(struct kvm_vcpu *vcpu, int number, bool level)
+{
+ int bit_index;
+ bool set;
+ unsigned long *ptr;
+
+ if (number == KVM_ARM_IRQ_CPU_IRQ)
+ bit_index = __ffs(HCR_VI);
+ else /* KVM_ARM_IRQ_CPU_FIQ */
+ bit_index = __ffs(HCR_VF);
+
+ ptr = (unsigned long *)&vcpu->arch.irq_lines;
+ if (level)
+ set = test_and_set_bit(bit_index, ptr);
+ else
+ set = test_and_clear_bit(bit_index, ptr);
+
+ /*
+ * If we didn't change anything, no need to wake up or kick other CPUs
+ */
+ if (set == level)
+ return 0;
+
+ /*
+ * The vcpu irq_lines field was updated, wake up sleeping VCPUs and
+ * trigger a world-switch round on the running physical CPU to set the
+ * virtual IRQ/FIQ fields in the HCR appropriately.
+ */
+ kvm_vcpu_kick(vcpu);
+
+ return 0;
+}
+
+int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level)
+{
+ u32 irq = irq_level->irq;
+ unsigned int irq_type, vcpu_idx, irq_num;
+ int nrcpus = atomic_read(&kvm->online_vcpus);
+ struct kvm_vcpu *vcpu = NULL;
+ bool level = irq_level->level;
+
+ irq_type = (irq >> KVM_ARM_IRQ_TYPE_SHIFT) & KVM_ARM_IRQ_TYPE_MASK;
+ vcpu_idx = (irq >> KVM_ARM_IRQ_VCPU_SHIFT) & KVM_ARM_IRQ_VCPU_MASK;
+ irq_num = (irq >> KVM_ARM_IRQ_NUM_SHIFT) & KVM_ARM_IRQ_NUM_MASK;
+
+ trace_kvm_irq_line(irq_type, vcpu_idx, irq_num, irq_level->level);
+
+ if (irq_type != KVM_ARM_IRQ_TYPE_CPU)
+ return -EINVAL;
+
+ if (vcpu_idx >= nrcpus)
+ return -EINVAL;
+
+ vcpu = kvm_get_vcpu(kvm, vcpu_idx);
+ if (!vcpu)
+ return -EINVAL;
+
+ if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
+ return -EINVAL;
+
+ return vcpu_interrupt_line(vcpu, irq_num, level);
+}
+
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{