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qemu/docs/specs/acpi_pci_hotplug.txt

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document QEMU<->ACPIBIOS PCI hotplug interface Document how QEMU communicates with ACPI BIOS for PCI hotplug. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-01-12 00:20:38 +08:00
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
acpi_piix4: Disallow write to up/down PCI hotplug registers The write side of these registers is never used and actually can't be used as defined because any read/modify/write sequence from the guest potentially races with qemu. Drop the write support and define these as read-only registers. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-06 01:07:08 +08:00
events. Read-only.
document QEMU<->ACPIBIOS PCI hotplug interface Document how QEMU communicates with ACPI BIOS for PCI hotplug. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-01-12 00:20:38 +08:00
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
acpi_piix4: Disallow write to up/down PCI hotplug registers The write side of these registers is never used and actually can't be used as defined because any read/modify/write sequence from the guest potentially races with qemu. Drop the write support and define these as read-only registers. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-06 01:07:08 +08:00
events. Read-only.
document QEMU<->ACPIBIOS PCI hotplug interface Document how QEMU communicates with ACPI BIOS for PCI hotplug. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-01-12 00:20:38 +08:00
PCI device eject (IO port 0xae08-0xae0b, 4-byte access):
----------------------------------------
acpi_piix4: Re-define PCI hotplug eject register read The PCI hotplug eject register has always returned 0, so let's redefine it as a hotplug feature register. The existing model of using separate up & down read-only registers and an eject via write to this register becomes the base implementation. As we make use of new interfaces we'll set bits here to allow the BIOS and AML implementation to optimize for the platform implementation. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-06 01:07:28 +08:00
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
document QEMU<->ACPIBIOS PCI hotplug interface Document how QEMU communicates with ACPI BIOS for PCI hotplug. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-01-12 00:20:38 +08:00
PCI removability status (IO port 0xae0c-0xae0f, 4-byte access):
-----------------------------------------------
Used by ACPI BIOS _RMV method to indicate removability status to OS. One
acpi_piix4: Remove PCI_RMV_BASE write code Clarify this register as read-only and remove write code. No change in existing behavior. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-06 01:07:21 +08:00
bit per slot. Read-only
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