Enhance the support for PCI legacy INTx interrupts and enable them in

the virtio backends.
- Add a new ioctl to export the count of pins on the I/O APIC from vmm
  to the hypervisor.
- Use pins on the I/O APIC >= 16 for PCI interrupts leaving 0-15 for
  ISA interrupts.
- Populate the MP Table with I/O interrupt entries for any PCI INTx
  interrupts.
- Create a _PRT table under the PCI root bridge in ACPI to route any
  PCI INTx interrupts appropriately.
- Track which INTx interrupts are in use per-slot so that functions
  that share a slot attempt to distribute their INTx interrupts across
  the four available pins.
- Implicitly mask INTx interrupts if either MSI or MSI-X is enabled
  and when the INTx DIS bit is set in a function's PCI command register.
  Either assert or deassert the associated I/O APIC pin when the
  state of one of those conditions changes.
- Add INTx support to the virtio backends.
- Always advertise the MSI capability in the virtio backends.

Submitted by:	neel (7)
Reviewed by:	neel
MFC after:	2 weeks

2 files changed, 8 insertions, 0 deletions

diff --git a/lib/libvmmapi/vmmapi.c b/lib/libvmmapi/vmmapi.c
index 6fec469..eba3367 100644
--- a/lib/libvmmapi/vmmapi.c
+++ b/lib/libvmmapi/vmmapi.c
@@ -454,6 +454,13 @@ vm_ioapic_pulse_irq(struct vmctx *ctx, int irq)
 }
 
 int
+vm_ioapic_pincount(struct vmctx *ctx, int *pincount)
+{
+
+	return (ioctl(ctx->fd, VM_IOAPIC_PINCOUNT, pincount));
+}
+
+int
 vm_inject_nmi(struct vmctx *ctx, int vcpu)
 {
 	struct vm_nmi vmnmi;
diff --git a/lib/libvmmapi/vmmapi.h b/lib/libvmmapi/vmmapi.h
index 69762c7..8428987 100644
--- a/lib/libvmmapi/vmmapi.h
+++ b/lib/libvmmapi/vmmapi.h
@@ -72,6 +72,7 @@ int	vm_lapic_msi(struct vmctx *ctx, uint64_t addr, uint64_t msg);
 int	vm_ioapic_assert_irq(struct vmctx *ctx, int irq);
 int	vm_ioapic_deassert_irq(struct vmctx *ctx, int irq);
 int	vm_ioapic_pulse_irq(struct vmctx *ctx, int irq);
+int	vm_ioapic_pincount(struct vmctx *ctx, int *pincount);
 int	vm_inject_nmi(struct vmctx *ctx, int vcpu);
 int	vm_capability_name2type(const char *capname);
 const char *vm_capability_type2name(int type);