kvm: Introduce core services for in-kernel irqchip support

Add the basic infrastructure to active in-kernel irqchip support, inject
interrupts into these models, and maintain IRQ routes.

Routing is optional and depends on the host arch supporting
KVM_CAP_IRQ_ROUTING. When it's not available on x86, we looe the HPET as
we can't route GSI0 to IOAPIC pin 2.

In-kernel irqchip support will once be controlled by the machine
property 'kernel_irqchip', but this is not yet wired up.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 1f56492cd..f6f4189f4 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -1939,3 +1939,14 @@ bool kvm_arch_stop_on_emulation_error(CPUState *env)
     return !(env->cr[0] & CR0_PE_MASK) ||
            ((env->segs[R_CS].selector  & 3) != 3);
 }
+
+void kvm_arch_init_irq_routing(KVMState *s)
+{
+    if (!kvm_check_extension(s, KVM_CAP_IRQ_ROUTING)) {
+        /* If kernel can't do irq routing, interrupt source
+         * override 0->2 cannot be set up as required by HPET.
+         * So we have to disable it.
+         */
+        no_hpet = 1;
+    }
+}