WAET

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The WAET (Windows ACPI Emulated Devices Table) is a table in ACPI running in guest partitions in a virtual machine environment.


For the latest information, see: Microsoft's WAET specifications


Windows ACPI Emulated Devices Table Format

ACPI Standard Header Field Byte length Byte offset Description
Signature 4 0x0 Signature for the WAET
Length 4 0x4 Length, in bytes, of the WAET
Revision 1 0x8 1
Checksum 1 0x9 Entire table, which must sum to zero
OEMID 6 0x10 Original equipment manufacturer (OEM) identifier (ID)
OEM Table ID 8 0x16 Manufacturer model ID
OEM Revision 4 0x24 OEM revision for supplied OEM table ID
Creator ID 4 0x28 Vendor ID of the ASL compiler utility that created the table
Creator Revision 4 0x32 Revision of the ASL compiler utility that created the table
Emulated Device Flags 4 0x36 Container of a bitmask of Windows behavior that this system requires

Emulated Device Flags

Bit offset Description
0 RTC good Indicates whether the RTC has been enhanced not to require acknowledgment after it asserts an interrupt. With this bit set, an interrupt handler can bypass reading the RTC register C to unlatch the pending interrupt.
1 ACPI PM timer good Indicates whether the ACPI PM timer has been enhanced not to require multiple reads. With this bit set, only one read of the ACPI PM timer is necessary to obtain a reliable value.
31:2 Reserved; must return 0 when read.

This explanation is a formated strict copy of the .docx document from https://download.microsoft.com/download/7/E/7/7E7662CF-CBEA-470B-A97E-CE7CE0D98DC2/WAET.docx