3ef77acab2
- implements QEMU hardware part of memory hotplug protocol described at "docs/specs/acpi_mem_hotplug.txt" - handles only memory add notification event for now Signed-off-by: Igor Mammedov <imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
45 lines
2 KiB
Plaintext
45 lines
2 KiB
Plaintext
QEMU<->ACPI BIOS memory hotplug interface
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--------------------------------------
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ACPI BIOS GPE.3 handler is dedicated for notifying OS about memory hot-add
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events.
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Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
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---------------------------------------------------------------
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0xa00:
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read access:
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[0x0-0x3] Lo part of memory device phys address
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[0x4-0x7] Hi part of memory device phys address
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[0x8-0xb] Lo part of memory device size in bytes
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[0xc-0xf] Hi part of memory device size in bytes
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[0x10-0x13] Memory device proximity domain
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[0x14] Memory device status fields
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bits:
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0: Device is enabled and may be used by guest
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1: Device insert event, used to distinguish device for which
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no device check event to OSPM was issued.
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It's valid only when bit 1 is set.
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2-7: reserved and should be ignored by OSPM
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[0x15-0x17] reserved
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write access:
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[0x0-0x3] Memory device slot selector, selects active memory device.
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All following accesses to other registers in 0xa00-0xa17
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region will read/store data from/to selected memory device.
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[0x4-0x7] OST event code reported by OSPM
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[0x8-0xb] OST status code reported by OSPM
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[0xc-0x13] reserved, writes into it are ignored
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[0x14] Memory device control fields
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bits:
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0: reserved, OSPM must clear it before writing to register
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1: if set to 1 clears device insert event, set by OSPM
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after it has emitted device check event for the
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selected memory device
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2-7: reserved, OSPM must clear them before writing to register
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Selecting memory device slot beyond present range has no effect on platform:
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- write accesses to memory hot-plug registers not documented above are
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ignored
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- read accesses to memory hot-plug registers not documented above return
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all bits set to 1.
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