[PATCH v3 06/17] cxl: docs/platform/example-configs documentation

Gregory Price
2025-05-12T16:21:52Z

Add example ACPI Table configurations for different sample platforms.

Signed-off-by: Gregory Price <gourry@gourry.net>
---
Documentation/driver-api/cxl/index.rst | 1 +
.../cxl/platform/example-configs.rst | 13 +
.../example-configurations/flexible.rst | 296 ++++++++++++++++++
.../example-configurations/hb-interleave.rst | 107 +++++++
.../multi-dev-per-hb.rst | 90 ++++++
.../example-configurations/one-dev-per-hb.rst | 136 ++++++++
6 files changed, 643 insertions(+)
create mode 100644 Documentation/driver-api/cxl/platform/example-configs.rst
create mode 100644 Documentation/driver-api/cxl/platform/example-configurations/flexible.rst
create mode 100644 Documentation/driver-api/cxl/platform/example-configurations/hb-interleave.rst
create mode 100644 Documentation/driver-api/cxl/platform/example-configurations/multi-dev-per-hb.rst
create mode 100644 Documentation/driver-api/cxl/platform/example-configurations/one-dev-per-hb.rst

diff --git a/Documentation/driver-api/cxl/index.rst b/Documentation/driver-api/cxl/index.rst
index 336322dc35a0..6a5fb7e00c52 100644
--- a/Documentation/driver-api/cxl/index.rst
+++ b/Documentation/driver-api/cxl/index.rst
@@ -27,6 +27,7 @@ that have impacts on each other. The docs here break up configurations steps.

platform/bios-and-efi
platform/acpi
+ platform/example-configs

.. toctree::
:maxdepth: 1
diff --git a/Documentation/driver-api/cxl/platform/example-configs.rst b/Documentation/driver-api/cxl/platform/example-configs.rst
new file mode 100644
index 000000000000..90a10d7473c6
--- /dev/null
+++ b/Documentation/driver-api/cxl/platform/example-configs.rst
@@ -0,0 +1,13 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Example Platform Configurations
+###############################
+
+.. toctree::
+ :maxdepth: 1
+ :caption: Contents
+
+ example-configurations/one-dev-per-hb.rst
+ example-configurations/multi-dev-per-hb.rst
+ example-configurations/hb-interleave.rst
+ example-configurations/flexible.rst
diff --git a/Documentation/driver-api/cxl/platform/example-configurations/flexible.rst b/Documentation/driver-api/cxl/platform/example-configurations/flexible.rst
new file mode 100644
index 000000000000..e39daba65fa0
--- /dev/null
+++ b/Documentation/driver-api/cxl/platform/example-configurations/flexible.rst
@@ -0,0 +1,296 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=====================
+Flexible Presentation
+=====================
+This system has a single socket with two CXL host bridges. Each host bridge
+has two CXL memory expanders with a 4GB of memory (32GB total).
+
+On this system, the platform designer wanted to provide the user flexibility
+to configure the memory devices in various interleave or NUMA node
+configurations. So they provided every combination.
+
+Things to note:
+
+* Cross-Bridge interleave is described in one CFMWS that covers all capacity.
+* One CFMWS is also described per-host bridge.
+* One CFMWS is also described per-device.
+* This SRAT describes one node for each of the above CFMWS.
+* The HMAT describes performance for each node in the SRAT.
+
+CEDT ::
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000007
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010370400000
+ Register length : 0000000000010000
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000006
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010380800000
+ Register length : 0000000000010000
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000001000000000
+ Window size : 0000000400000000
+ Interleave Members (2^n) : 01
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+ Second Target : 00000006
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000002000000000
+ Window size : 0000000200000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000002200000000
+ Window size : 0000000200000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000006
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000003000000000
+ Window size : 0000000100000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000003100000000
+ Window size : 0000000100000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000003200000000
+ Window size : 0000000100000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000006
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000003300000000
+ Window size : 0000000100000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000006
+
+SRAT ::
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000001
+ Reserved1 : 0000
+ Base Address : 0000001000000000
+ Address Length : 0000000400000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000002
+ Reserved1 : 0000
+ Base Address : 0000002000000000
+ Address Length : 0000000200000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000003
+ Reserved1 : 0000
+ Base Address : 0000002200000000
+ Address Length : 0000000200000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000004
+ Reserved1 : 0000
+ Base Address : 0000003000000000
+ Address Length : 0000000100000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000005
+ Reserved1 : 0000
+ Base Address : 0000003100000000
+ Address Length : 0000000100000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000006
+ Reserved1 : 0000
+ Base Address : 0000003200000000
+ Address Length : 0000000100000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000007
+ Reserved1 : 0000
+ Base Address : 0000003300000000
+ Address Length : 0000000100000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+HMAT ::
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 00 [Latency]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Target Proximity Domain List : 00000002
+ Target Proximity Domain List : 00000003
+ Target Proximity Domain List : 00000004
+ Target Proximity Domain List : 00000005
+ Target Proximity Domain List : 00000006
+ Target Proximity Domain List : 00000007
+ Entry : 0080
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 03 [Bandwidth]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Target Proximity Domain List : 00000002
+ Target Proximity Domain List : 00000003
+ Target Proximity Domain List : 00000004
+ Target Proximity Domain List : 00000005
+ Target Proximity Domain List : 00000006
+ Target Proximity Domain List : 00000007
+ Entry : 1200
+ Entry : 0400
+ Entry : 0200
+ Entry : 0200
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+ Entry : 0100
+
+SLIT ::
+
+ Signature : "SLIT" [System Locality Information Table]
+ Localities : 0000000000000003
+ Locality 0 : 10 20 20 20 20 20 20 20
+ Locality 1 : FF 0A FF FF FF FF FF FF
+ Locality 2 : FF FF 0A FF FF FF FF FF
+ Locality 3 : FF FF FF 0A FF FF FF FF
+ Locality 4 : FF FF FF FF 0A FF FF FF
+ Locality 5 : FF FF FF FF FF 0A FF FF
+ Locality 6 : FF FF FF FF FF FF 0A FF
+ Locality 7 : FF FF FF FF FF FF FF 0A
+
+DSDT ::
+
+ Scope (_SB)
+ {
+ Device (S0D0)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x07) // _UID: Unique ID
+ }
+ ...
+ Device (S0D5)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x06) // _UID: Unique ID
+ }
+ }
diff --git a/Documentation/driver-api/cxl/platform/example-configurations/hb-interleave.rst b/Documentation/driver-api/cxl/platform/example-configurations/hb-interleave.rst
new file mode 100644
index 000000000000..ce07e6162f26
--- /dev/null
+++ b/Documentation/driver-api/cxl/platform/example-configurations/hb-interleave.rst
@@ -0,0 +1,107 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============================
+Cross-Host-Bridge Interleave
+============================
+This system has a single socket with two CXL host bridges. Each host bridge
+has a single CXL memory expander with a 4GB of memory.
+
+Things to note:
+
+* Cross-Bridge interleave is described.
+* The expanders are described by a single CFMWS.
+* This SRAT describes one node for both host bridges.
+* The HMAT describes a single node's performance.
+
+CEDT ::
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000007
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010370400000
+ Register length : 0000000000010000
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000006
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010380800000
+ Register length : 0000000000010000
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000001000000000
+ Window size : 0000000200000000
+ Interleave Members (2^n) : 01
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+ Second Target : 00000006
+
+SRAT ::
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000001
+ Reserved1 : 0000
+ Base Address : 0000001000000000
+ Address Length : 0000000200000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+HMAT ::
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 00 [Latency]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Target Proximity Domain List : 00000002
+ Entry : 0080
+ Entry : 0100
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 03 [Bandwidth]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Target Proximity Domain List : 00000002
+ Entry : 1200
+ Entry : 0400
+
+SLIT ::
+
+ Signature : "SLIT" [System Locality Information Table]
+ Localities : 0000000000000003
+ Locality 0 : 10 20
+ Locality 1 : FF 0A
+
+DSDT ::
+
+ Scope (_SB)
+ {
+ Device (S0D0)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x07) // _UID: Unique ID
+ }
+ ...
+ Device (S0D5)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x06) // _UID: Unique ID
+ }
+ }
diff --git a/Documentation/driver-api/cxl/platform/example-configurations/multi-dev-per-hb.rst b/Documentation/driver-api/cxl/platform/example-configurations/multi-dev-per-hb.rst
new file mode 100644
index 000000000000..6adf7c639490
--- /dev/null
+++ b/Documentation/driver-api/cxl/platform/example-configurations/multi-dev-per-hb.rst
@@ -0,0 +1,90 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================================
+Multiple Devices per Host Bridge
+================================
+
+In this example system we will have a single socket and one CXL host bridge.
+There are two CXL memory expanders with 4GB attached to the host bridge.
+
+Things to note:
+
+* Intra-Bridge interleave is not described here.
+* The expanders are described by a single CEDT/CFMWS.
+* This CEDT/SRAT describes one node for both devices.
+* There is only one proximity domain the HMAT for both devices.
+
+CEDT ::
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000007
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010370400000
+ Register length : 0000000000010000
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000001000000000
+ Window size : 0000000200000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+
+SRAT ::
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000001
+ Reserved1 : 0000
+ Base Address : 0000001000000000
+ Address Length : 0000000200000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+HMAT ::
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 00 [Latency]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Entry : 0080
+ Entry : 0100
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 03 [Bandwidth]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Entry : 1200
+ Entry : 0200
+
+SLIT ::
+
+ Signature : "SLIT" [System Locality Information Table]
+ Localities : 0000000000000003
+ Locality 0 : 10 20
+ Locality 1 : FF 0A
+
+DSDT ::
+
+ Scope (_SB)
+ {
+ Device (S0D0)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x07) // _UID: Unique ID
+ }
+ ...
+ }
diff --git a/Documentation/driver-api/cxl/platform/example-configurations/one-dev-per-hb.rst b/Documentation/driver-api/cxl/platform/example-configurations/one-dev-per-hb.rst
new file mode 100644
index 000000000000..b89ba3cab98f
--- /dev/null
+++ b/Documentation/driver-api/cxl/platform/example-configurations/one-dev-per-hb.rst
@@ -0,0 +1,136 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+One Device per Host Bridge
+==========================
+
+This system has a single socket with two CXL host bridges. Each host bridge
+has a single CXL memory expander with a 4GB of memory.
+
+Things to note:
+
+* Cross-Bridge interleave is not being used.
+* The expanders are in two separate but adjascent memory regions.
+* This CEDT/SRAT describes one node per device
+* The expanders have the same performance and will be in the same memory tier.
+
+CEDT ::
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000007
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010370400000
+ Register length : 0000000000010000
+
+ Subtable Type : 00 [CXL Host Bridge Structure]
+ Reserved : 00
+ Length : 0020
+ Associated host bridge : 00000006
+ Specification version : 00000001
+ Reserved : 00000000
+ Register base : 0000010380800000
+ Register length : 0000000000010000
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000001000000000
+ Window size : 0000000100000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000007
+
+ Subtable Type : 01 [CXL Fixed Memory Window Structure]
+ Reserved : 00
+ Length : 002C
+ Reserved : 00000000
+ Window base address : 0000001100000000
+ Window size : 0000000100000000
+ Interleave Members (2^n) : 00
+ Interleave Arithmetic : 00
+ Reserved : 0000
+ Granularity : 00000000
+ Restrictions : 0006
+ QtgId : 0001
+ First Target : 00000006
+
+SRAT ::
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000001
+ Reserved1 : 0000
+ Base Address : 0000001000000000
+ Address Length : 0000000100000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+ Subtable Type : 01 [Memory Affinity]
+ Length : 28
+ Proximity Domain : 00000002
+ Reserved1 : 0000
+ Base Address : 0000001100000000
+ Address Length : 0000000100000000
+ Reserved2 : 00000000
+ Flags (decoded below) : 0000000B
+ Enabled : 1
+ Hot Pluggable : 1
+ Non-Volatile : 0
+
+HMAT ::
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 00 [Latency]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Target Proximity Domain List : 00000002
+ Entry : 0080
+ Entry : 0100
+ Entry : 0100
+
+ Structure Type : 0001 [SLLBI]
+ Data Type : 03 [Bandwidth]
+ Target Proximity Domain List : 00000000
+ Target Proximity Domain List : 00000001
+ Target Proximity Domain List : 00000002
+ Entry : 1200
+ Entry : 0200
+ Entry : 0200
+
+SLIT ::
+
+ Signature : "SLIT" [System Locality Information Table]
+ Localities : 0000000000000003
+ Locality 0 : 10 20 20
+ Locality 1 : FF 0A FF
+ Locality 2 : FF FF 0A
+
+DSDT ::
+
+ Scope (_SB)
+ {
+ Device (S0D0)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x07) // _UID: Unique ID
+ }
+ ...
+ Device (S0D5)
+ {
+ Name (_HID, "ACPI0016" /* Compute Express Link Host Bridge */) // _HID: Hardware ID
+ ...
+ Name (_UID, 0x06) // _UID: Unique ID
+ }
+ }
--
2.49.0