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9290f364c1
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>
46 lines
1.7 KiB
Plaintext
46 lines
1.7 KiB
Plaintext
QEMU<->ACPI BIOS PCI hotplug interface
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--------------------------------------
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QEMU supports PCI hotplug via ACPI, for PCI bus 0. This document
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describes the interface between QEMU and the ACPI BIOS.
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ACPI GPE block (IO ports 0xafe0-0xafe3, byte access):
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-----------------------------------------
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Generic ACPI GPE block. Bit 1 (GPE.1) used to notify PCI hotplug/eject
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event to ACPI BIOS, via SCI interrupt.
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PCI slot injection notification pending (IO port 0xae00-0xae03, 4-byte access):
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---------------------------------------------------------------
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Slot injection notification pending. One bit per slot.
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Read by ACPI BIOS GPE.1 handler to notify OS of injection
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events. Read-only.
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PCI slot removal notification (IO port 0xae04-0xae07, 4-byte access):
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-----------------------------------------------------
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Slot removal notification pending. One bit per slot.
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Read by ACPI BIOS GPE.1 handler to notify OS of removal
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events. Read-only.
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PCI device eject (IO port 0xae08-0xae0b, 4-byte access):
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----------------------------------------
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Write: Used by ACPI BIOS _EJ0 method to request device removal.
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One bit per slot.
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Read: Hotplug features register. Used by platform to identify features
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available. Current base feature set (no bits set):
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- Read-only "up" register @0xae00, 4-byte access, bit per slot
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- Read-only "down" register @0xae04, 4-byte access, bit per slot
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- Read/write "eject" register @0xae08, 4-byte access,
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write: bit per slot eject, read: hotplug feature set
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- Read-only hotplug capable register @0xae0c, 4-byte access, bit per slot
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PCI removability status (IO port 0xae0c-0xae0f, 4-byte access):
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-----------------------------------------------
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Used by ACPI BIOS _RMV method to indicate removability status to OS. One
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bit per slot. Read-only
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