Userspace can inject IRQs and FIQs through the KVM_IRQ_LINE VM ioctl.
This ioctl is used since the sematics are in fact two lines that can be
either raised or lowered on the VCPU - the IRQ and FIQ lines.
KVM needs to know which VCPU it must operate on and whether the FIQ or
IRQ line is raised/lowered. Hence both pieces of information is packed
in the kvm_irq_level->irq field. The irq fild value will be:
IRQ: vcpu_index * 2
FIQ: (vcpu_index * 2) + 1
This is documented in Documentation/kvm/api.txt.
The effect of the ioctl is simply to simply raise/lower the
corresponding virt_irq field on the VCPU struct, which will cause the
world-switch code to raise/lower virtual interrupts when running the
guest on next switch. The wait_for_interrupt flag is also cleared for
raised IRQs causing an idle VCPU to become active again.
Signed-off-by: Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
---
Documentation/kvm/api.txt | 11 ++++++--
arch/arm/include/asm/kvm.h | 8 ++++++
arch/arm/include/asm/kvm_arm.h | 1 +
arch/arm/kvm/arm.c | 54 +++++++++++++++++++++++++++++++++++++++-
arch/arm/kvm/trace.h | 21 ++++++++++++++++
include/linux/kvm.h | 1 +
6 files changed, 91 insertions(+), 5 deletions(-)
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 9bef4e4..1ed5554 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -534,15 +534,20 @@ only go to the IOAPIC. On ia64, a IOSAPIC is created.
4.25 KVM_IRQ_LINE
Capability: KVM_CAP_IRQCHIP
-Architectures: x86, ia64
+Architectures: x86, ia64, arm
Type: vm ioctl
Parameters: struct kvm_irq_level
Returns: 0 on success, -1 on error
Sets the level of a GSI input to the interrupt controller model in the kernel.
Requires that an interrupt controller model has been previously created with
-KVM_CREATE_IRQCHIP. Note that edge-triggered interrupts require the level
-to be set to 1 and then back to 0.
+KVM_CREATE_IRQCHIP (except for ARM). Note that edge-triggered interrupts
+require the level to be set to 1 and then back to 0.
+
+ARM uses two types of interrupt lines per CPU, ie. IRQ and FIQ. The value of the
+irq field should be (VCPU_INDEX * 2) for IRQs and ((VCPU_INDEX * 2) + 1) for
+FIQs. Level is used to raise/lower the line. See arch/arm/include/asm/kvm.h for
+convenience macros.
struct kvm_irq_level {
union {
diff --git a/arch/arm/include/asm/kvm.h b/arch/arm/include/asm/kvm.h
index 87dc33b..8935062 100644
--- a/arch/arm/include/asm/kvm.h
+++ b/arch/arm/include/asm/kvm.h
@@ -20,6 +20,14 @@
#include <asm/types.h>
/*
+ * KVM_IRQ_LINE macros to set/read IRQ/FIQ for specific VCPU index.
+ */
+enum KVM_ARM_IRQ_LINE_TYPE {
+ KVM_ARM_IRQ_LINE = 0,
+ KVM_ARM_FIQ_LINE = 1,
+};
+
+/*
* Modes used for short-hand mode determinition in the world-switch code and
* in emulation code.
*
diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index 835abd1..e378a37 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -49,6 +49,7 @@
#define HCR_VM 1
#define HCR_GUEST_MASK (HCR_TSC | HCR_TWE | HCR_TWI | HCR_VM | HCR_AMO | \
HCR_AMO | HCR_IMO | HCR_FMO | HCR_SWIO)
+#define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF)
/* Hyp System Control Register (HSCTLR) bits */
#define HSCTLR_TE (1 << 30)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 3db6794..071912e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -297,6 +297,43 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
return -EINVAL;
}
+static int kvm_arch_vm_ioctl_irq_line(struct kvm *kvm,
+ struct kvm_irq_level *irq_level)
+{
+ u32 mask;
+ unsigned int vcpu_idx;
+ struct kvm_vcpu *vcpu;
+
+ vcpu_idx = irq_level->irq / 2;
+ if (vcpu_idx >= KVM_MAX_VCPUS)
+ return -EINVAL;
+
+ vcpu = kvm_get_vcpu(kvm, vcpu_idx);
+ if (!vcpu)
+ return -EINVAL;
+
+ switch (irq_level->irq % 2) {
+ case KVM_ARM_IRQ_LINE:
+ mask = HCR_VI;
+ break;
+ case KVM_ARM_FIQ_LINE:
+ mask = HCR_VF;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ trace_kvm_irq_line(irq_level->irq % 2, irq_level->level, vcpu_idx);
+
+ if (irq_level->level) {
+ vcpu->arch.virt_irq |= mask;
+ vcpu->arch.wait_for_interrupts = 0;
+ } else
+ vcpu->arch.virt_irq &= ~mask;
+
+ return 0;
+}
+
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -312,8 +349,21 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
- printk(KERN_ERR "kvm_arch_vm_ioctl: Unsupported ioctl (%d)\n", ioctl);
- return -EINVAL;
+ struct kvm *kvm = filp->private_data;
+ void __user *argp = (void __user *)arg;
+
+ switch (ioctl) {
+ case KVM_IRQ_LINE: {
+ struct kvm_irq_level irq_event;
+
+ if (copy_from_user(&irq_event, argp, sizeof irq_event))
+ return -EFAULT;
+ return kvm_arch_vm_ioctl_irq_line(kvm, &irq_event);
+ }
+ default:
+ kvm_err(-EINVAL, "Unsupported ioctl (%d)", ioctl);
+ return -EINVAL;
+ }
}
/**
diff --git a/arch/arm/kvm/trace.h b/arch/arm/kvm/trace.h
index f8869c1..ac64e3a 100644
--- a/arch/arm/kvm/trace.h
+++ b/arch/arm/kvm/trace.h
@@ -40,6 +40,27 @@ TRACE_EVENT(kvm_exit,
);
+TRACE_EVENT(kvm_irq_line,
+ TP_PROTO(unsigned int type, unsigned int level, unsigned int vcpu_idx),
+ TP_ARGS(type, level, vcpu_idx),
+
+ TP_STRUCT__entry(
+ __field( unsigned int, type )
+ __field( unsigned int, level )
+ __field( unsigned int, vcpu_idx )
+ ),
+
+ TP_fast_assign(
+ __entry->type = type;
+ __entry->level = level;
+ __entry->vcpu_idx = vcpu_idx;
+ ),
+
+ TP_printk("KVM_IRQ_LINE: type: %s, level: %u, vcpu: %u",
+ (__entry->type == KVM_ARM_IRQ_LINE) ? "IRQ" : "FIQ",
+ __entry->level, __entry->vcpu_idx)
+);
+
#endif /* _TRACE_KVM_H */
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index ea2dc1a..4e85b4a 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -111,6 +111,7 @@ struct kvm_irq_level {
* ACPI gsi notion of irq.
* For IA-64 (APIC model) IOAPIC0: irq 0-23; IOAPIC1: irq 24-47..
* For X86 (standard AT mode) PIC0/1: irq 0-15. IOAPIC0: 0-23..
+ * For ARM: IRQ: irq = (2*vcpu_index). FIQ: irq = (2*vcpu_indx + 1).
*/
union {
__u32 irq;
--
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