@@ -237,6 +237,23 @@ group and can access them as follows:
/* Gratuitous device reset and go... */
ioctl(device, VFIO_DEVICE_RESET);
+For platform devices, if a device has multiple regions and multiple IRQs the
+index that will be assigned by VFIO to those resources will correspond to the
+order within the associated "reg" and "interrupt" properties in the device tree
+representation of the target device.
+
+For example, if a device is represented like this in the device tree:
+
+ reg = <0x101e2000 0x1000 0x101e4000 0x1000>;
+ interrupts = <24 25 26 27>;
+
+Region #0 is 0x101e2000, region #1 is 0x101e4000
+Interrupt #0 is 24, and so on.
+
+Additionally for a platform device, unlike PCI devices, an offset referring to
+a region within a VFIO device file descriptor will match the physical address
+of that region as defined in the device tree.
+
VFIO User API
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