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authorChristoffer Dall <cdall@cs.columbia.edu>2013-01-21 03:28:08 +0400
committerChristoffer Dall <c.dall@virtualopensystems.com>2013-01-23 22:29:12 +0400
commit86ce85352f0da7e1431ad8efcb04323819a620e7 (patch)
tree0f5a0a971b0092c9cfd74659254f76a4c7117294 /Documentation/virtual
parentd5d8184d35c990b1324d9b30bcd0e4e8aa08f56d (diff)
downloadlinux-86ce85352f0da7e1431ad8efcb04323819a620e7.tar.xz
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>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/api.txt25
1 files changed, 21 insertions, 4 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 4237c27ea612..505049299298 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -615,15 +615,32 @@ 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.
+On some architectures it is required 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.
+
+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_id |
+
+The irq_type field has the following values:
+- irq_type[0]: out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ
+- irq_type[1]: in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.)
+ (the vcpu_index field is ignored)
+- irq_type[2]: in-kernel GIC: PPI, irq_id between 16 and 31 (incl.)
+
+(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs)
+
+In both cases, level is used to raise/lower the line.
struct kvm_irq_level {
union {