| 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. | 
 |  | 
 | 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. | 
 |  | 
 | PCI device eject (IO port 0xae08-0xae0b, 4-byte access): | 
 | ---------------------------------------- | 
 |  | 
 | Used by ACPI BIOS _EJ0 method to request device removal. One bit per slot. | 
 | Reads return 0. | 
 |  | 
 | 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. |