1QEMU<->ACPI BIOS PCI hotplug interface
2======================================
3
4QEMU supports PCI hotplug via ACPI, for PCI bus 0. This document
5describes the interface between QEMU and the ACPI BIOS.
6
7ACPI GPE block (IO ports 0xafe0-0xafe3, byte access)
8----------------------------------------------------
9
10Generic ACPI GPE block. Bit 1 (GPE.1) used to notify PCI hotplug/eject
11event to ACPI BIOS, via SCI interrupt.
12
13PCI slot injection notification pending (IO port 0xae00-0xae03, 4-byte access)
14------------------------------------------------------------------------------
15
16Slot injection notification pending. One bit per slot.
17
18Read by ACPI BIOS GPE.1 handler to notify OS of injection
19events.  Read-only.
20
21PCI slot removal notification (IO port 0xae04-0xae07, 4-byte access)
22--------------------------------------------------------------------
23
24Slot removal notification pending. One bit per slot.
25
26Read by ACPI BIOS GPE.1 handler to notify OS of removal
27events.  Read-only.
28
29PCI device eject (IO port 0xae08-0xae0b, 4-byte access)
30-------------------------------------------------------
31
32Write: Used by ACPI BIOS _EJ0 method to request device removal.
33One bit per slot.
34
35Read: Hotplug features register.  Used by platform to identify features
36available.  Current base feature set (no bits set):
37
38- Read-only "up" register @0xae00, 4-byte access, bit per slot
39- Read-only "down" register @0xae04, 4-byte access, bit per slot
40- Read/write "eject" register @0xae08, 4-byte access,
41  write: bit per slot eject, read: hotplug feature set
42- Read-only hotplug capable register @0xae0c, 4-byte access, bit per slot
43
44PCI removability status (IO port 0xae0c-0xae0f, 4-byte access)
45--------------------------------------------------------------
46
47Used by ACPI BIOS _RMV method to indicate removability status to OS. One
48bit per slot.  Read-only.
49