LibreOffice/5.2.3.3$Linux_X86_64 LibreOffice_project/20m0$Build-3 0 2342 17861 7788 true false view2 3041 3464 2342 0 20202 7786 1 1 false 228 false false true true true 0 true true false false true false true false true true true true true false true true false false true false true true false false false true false true true false true false false 1430233 false false true false true true false false 0 false true high-resolution false false false false true true true false false false true false false false true true 1362860 true 1 true false false 0 false false false ACPI Specification for Xen Environment Table Specification: LINARO-0003 Author: Parth Dixit<parth.dixit@linaro.org>, Julien Grall<julien.grall@citrix.com> Revision History: Version Date Comments 0.1 4 December 2014 Initial draft. 0.2 4 January 2015 First Revision Title: Define Xen Environment table for passing Xen specific information to DOM0. License: This work is licensed under the BSD License. To view a copy of this license, visit http://opensource.org/licenses/BSD-3-Clause. Problem Statement: DOM0(Linux) requires additional information about the Xen environment for proper communication with Xen. DOM0 shares some memory pages with Xen and it need the address and size of the memory allocated to it. DOM0 also needs to configure interrupt that will be used for notification of events. The Xen Environment Table: This specification lays out the structure and content of a new ACPI table – the Xen Environment Table (XENV). This table, while not currently part of the ACPI specification, may or may not become part of the specification at a later date. The purpose of the XENV is to pass the starting memory address,memory size and event channel interrupt from Xen to DOM0. The structure of the XENV is defined in Table 1. Table 1. Xen Environment Table Field Byte Length Byte Offset Description Signature 4 0 XENV to indicate that this is the Xen Environment Table. Length 4 4 Length in bytes of the entire Table Revision 1 8 1 – current revision level of the XENV Checksum 1 9 Standard ACPI table checksum; i.e., the entire table must sum to zero OEMID 6 10 OEM ID OEM Table ID 8 16 OEM model ID OEM Revision 4 24 OEM Revision of the XENV for the OEM Table ID Creator ID 4 28 Vendor ID of the utility that created the table Creator Revision 4 32 Revision of the utility that created the table GNT Start 8 36 Starting address of the Grant Table Region GNT Size 8 44 Size of the Grant Table Region Evtchn Intr 4 52 PPI used to notify an event channel Evtchn Intr Flags 1 56 Flags for the Evtchn Intr The Grant Table region is optional. If not provided, the field “GNT Size" must be 0. The field "GNT start" is unknown. The Event Channel Interrupt is optional. If not provided, the field "Evtchn Intr" must be 0 (consistent with other tables such as the GTDT). The field "Evtchn intr flags" is unknown. Flags Definition for the Evtchn intr are defined in Table 2. Table 2. Evtchn Intr Flags Bit Field Bit Offset Number of bits Description Evtchn Intr Mode 0 1 This bit indicates the mode of the Evtchn Intr 1: Interrupt is Edge triggered 0: Interrupt is Level triggered Evtchn Intr Polarity 1 1 This bit indicates the polarity the Evtchn Intr 1: Interrupt is Active low 0: Interrupt is Active high Reserved 2 2 Reserved, must be zero Example: Below, we define a simple table with arbitrary address and interrupt number: /* * Template for [XENV] ACPI Table * Format: [ByteLength] FieldName : HexFieldValue */ [0004] Signature : “XENV” // Xen Environment Table [0004] Table Length : 00000000 [0001] Revision : 01 [0001] Checksum : 00 [0006] Oem ID : "XenVMM" [0008] Oem Table ID : "TEMPLATE" [0004] Oem Revision : 00000000 [0004] Asl Compiler ID : "INTL" [0004] Asl Compiler Revision : 20140214 [0008] GNT Start : 0000000010000000 [0008] GNT Size : 0000000000002000 [0004] Evtchn Intr : 25 [0001] Evtchn Intr Flags(decoded below) : 03 Evtchn Intr Mode : 1 Evtchn Intr Polarity : 1