Document how QEMU communicates with ACPI BIOS for PCI hotplug. Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>
--- /dev/null 2010-12-14 09:23:48.414180082 -0200 +++ qemu/docs/specs/acpi_pci_hotplug.txt 2010-12-20 15:00:26.000000000 -0200 @@ -0,0 +1,39 @@ +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 0xafe00-0xafe04): +----------------------------------------- + +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): +--------------------------------------------------------------- +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): +----------------------------------------------------- +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): +---------------------------------------- + +Used by ACPI BIOS _EJ0 method to request device removal. One bit per slot. +Reads return 0. + +PCI removability status (IO port 0xae0c-0xae0f): +----------------------------------------------- + +Used by ACPI BIOS _RMV method to indicate removability status to OS. One +bit per slot. + +
