import

qemu/docs/specs/acpi_pci_hotplug.txt

@@ -0,0 +1,45 @@
+QEMU<->ACPI BIOS PCI hotplug interface
+--------------------------------------
+
+QEMU supports PCI hotplug via ACPI, for PCI bus 0. This document
+describes the interface between QEMU and the ACPI BIOS.
+
+ACPI GPE block (IO ports 0xafe0-0xafe3, byte access):
+-----------------------------------------
+
+Generic ACPI GPE block. Bit 1 (GPE.1) used to notify PCI hotplug/eject
+event to ACPI BIOS, via SCI interrupt.
+
+PCI slot injection notification pending (IO port 0xae00-0xae03, 4-byte access):
+---------------------------------------------------------------
+Slot injection notification pending. One bit per slot.
+
+Read by ACPI BIOS GPE.1 handler to notify OS of injection
+events.  Read-only.
+
+PCI slot removal notification (IO port 0xae04-0xae07, 4-byte access):
+-----------------------------------------------------
+Slot removal notification pending. One bit per slot.
+
+Read by ACPI BIOS GPE.1 handler to notify OS of removal
+events.  Read-only.
+
+PCI device eject (IO port 0xae08-0xae0b, 4-byte access):
+----------------------------------------
+
+Write: Used by ACPI BIOS _EJ0 method to request device removal.
+One bit per slot.
+
+Read: Hotplug features register.  Used by platform to identify features
+available.  Current base feature set (no bits set):
+ - Read-only "up" register @0xae00, 4-byte access, bit per slot
+ - Read-only "down" register @0xae04, 4-byte access, bit per slot
+ - Read/write "eject" register @0xae08, 4-byte access,
+   write: bit per slot eject, read: hotplug feature set
+ - Read-only hotplug capable register @0xae0c, 4-byte access, bit per slot
+
+PCI removability status (IO port 0xae0c-0xae0f, 4-byte access):
+-----------------------------------------------
+
+Used by ACPI BIOS _RMV method to indicate removability status to OS. One
+bit per slot.  Read-only