9c046d96d4
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>
38 lines
1.3 KiB
Plaintext
38 lines
1.3 KiB
Plaintext
QEMU<->ACPI BIOS PCI hotplug interface
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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.
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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.
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PCI device eject (IO port 0xae08-0xae0b, 4-byte access):
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----------------------------------------
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Used by ACPI BIOS _EJ0 method to request device removal. One bit per slot.
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Reads return 0.
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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.
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