microvm: add irq table

Add a comment with a table listing the IRQs,
both legacy pc and microvm side-by-side.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 20200928104256.9241-5-kraxel@redhat.com

include/hw/i386/microvm.h

@@ -27,6 +27,28 @@
 #include "hw/acpi/acpi_dev_interface.h"
 #include "qom/object.h"
 
+/*
+ *  IRQ    |  pc        | microvm (acpi=on)
+ * --------+------------+------------------
+ *   0     |  pit       |
+ *   1     |  kbd       |
+ *   2     |  cascade   |
+ *   3     |  serial 1  |
+ *   4     |  serial 0  | serial
+ *   5     |  -         |
+ *   6     |  floppy    |
+ *   7     |  parallel  |
+ *   8     |  rtc       | rtc (rtc=on)
+ *   9     |  acpi      | acpi (ged)
+ *  10     |  pci lnk   |
+ *  11     |  pci lnk   |
+ *  12     |  ps2       |
+ *  13     |  fpu       |
+ *  14     |  ide 0     |
+ *  15     |  ide 1     |
+ *  16-23  |  pci gsi   | virtio
+ */
+
 /* Platform virtio definitions */
 #define VIRTIO_MMIO_BASE      0xfeb00000
 #define VIRTIO_NUM_TRANSPORTS 8