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KVM: ARM: Inject IRQs and FIQs from userspace

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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>
This commit is contained in:
Christoffer Dall 2013-01-20 18:28:08 -05:00 • committed by Christoffer Dall
commit 86ce85352f
6 changed files with 134 additions and 4 deletions
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include/uapi/linux/kvm.h
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@ -115,6 +115,7 @@ 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: See Documentation/virtual/kvm/api.txt
*/
union {
__u32 irq;