Merge tag 'cxl-for-6.9' of git:https://git.kernel.org/pub/scm/linux/kernel/…

…git/cxl/cxl

Pull CXL updates from Dan Williams:
 "CXL has mechanisms to enumerate the performance characteristics of
  memory devices. Those mechanisms allow Linux to build the equivalent
  of ACPI SRAT, SLIT, and HMAT tables dynamically at runtime. That
  capability is necessary because static ACPI can not represent dynamic
  CXL configurations (and reconfigurations).

  So, building on the v6.8 work to add "Quality of Service" enumeration,
  this update plumbs CXL "access coordinates" (read/write access latency
  and bandwidth) in all the same places that ACPI HMAT feeds similar
  data. Follow-on patches from the -mm side can then use that data to
  feed mechanisms like mm/memory-tiers.c. Greg has acked the touch to
  drivers/base/.

  The other feature update this cycle is support for CXL error injection
  via the ACPI EINJ module. That facility enables injection of bus
  protocol errors provided the user knows the magic address values to
  insert in the interface. To hide that magic, and make this easier to
  use, new error injection attributes were added to CXL debugfs. That
  interface injects the errors relative to a CXL object rather than
  require user tooling to know how to lookup and inject RCRB (Root
  Complex Register Block) addresses into the raw EINJ debugfs interface.
  It received some helpful review comments from Tony, but no explicit
  acks from the ACPI side. The primary user visible change for existing
  EINJ users is that they may find that einj.ko was already loaded by
  cxl_core.ko. Previously, einj.ko was only loaded on demand.

  The usual collection of miscellaneous cleanups are also present this
  cycle.

  Summary:

   - Supplement ACPI HMAT reported memory performance with native CXL
     memory performance enumeration

   - Add support for CXL error injection via the ACPI EINJ mechanism

   - Cleanup CXL DOE and CDAT integration

   - Miscellaneous cleanups and fixes"

* tag 'cxl-for-6.9' of git:https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (21 commits)
  Documentation/ABI/testing/debugfs-cxl: Fix "Unexpected indentation"
  lib/firmware_table: Provide buffer length argument to cdat_table_parse()
  cxl/pci: Get rid of pointer arithmetic reading CDAT table
  cxl/pci: Rename DOE mailbox handle to doe_mb
  cxl: Fix the incorrect assignment of SSLBIS entry pointer initial location
  cxl/core: Add CXL EINJ debugfs files
  EINJ, Documentation: Update EINJ kernel doc
  EINJ: Add CXL error type support
  EINJ: Migrate to a platform driver
  cxl/region: Deal with numa nodes not enumerated by SRAT
  cxl/region: Add memory hotplug notifier for cxl region
  cxl/region: Add sysfs attribute for locality attributes of CXL regions
  cxl/region: Calculate performance data for a region
  cxl: Set cxlmd->endpoint before adding port device
  cxl: Move QoS class to be calculated from the nearest CPU
  cxl: Split out host bridge access coordinates
  cxl: Split out combine_coordinates() for common shared usage
  ACPI: HMAT / cxl: Add retrieval of generic port coordinates for both access classes
  ACPI: HMAT: Introduce 2 levels of generic port access class
  base/node / ACPI: Enumerate node access class for 'struct access_coordinate'
  ...

Documentation/ABI/testing/debugfs-cxl

@@ -33,3 +33,37 @@ Description:
  device cannot clear poison from the address, -ENXIO is returned.
  The clear_poison attribute is only visible for devices
  supporting the capability.
+
+What: /sys/kernel/debug/cxl/einj_types
+Date: January, 2024
+KernelVersion: v6.9
+Contact: [email protected]
+Description:
+ (RO) Prints the CXL protocol error types made available by
+ the platform in the format:
+
+ 0x<error number> <error type>
+
+ The possible error types are (as of ACPI v6.5):
+
+ 0x1000 CXL.cache Protocol Correctable
+ 0x2000 CXL.cache Protocol Uncorrectable non-fatal
+ 0x4000 CXL.cache Protocol Uncorrectable fatal
+ 0x8000 CXL.mem Protocol Correctable
+ 0x10000 CXL.mem Protocol Uncorrectable non-fatal
+ 0x20000 CXL.mem Protocol Uncorrectable fatal
+
+ The <error number> can be written to einj_inject to inject
+ <error type> into a chosen dport.
+
+What: /sys/kernel/debug/cxl/$dport_dev/einj_inject
+Date: January, 2024
+KernelVersion: v6.9
+Contact: [email protected]
+Description:
+ (WO) Writing an integer to this file injects the corresponding
+ CXL protocol error into $dport_dev ($dport_dev will be a device
+ name from /sys/bus/pci/devices). The integer to type mapping for
+ injection can be found by reading from einj_types. If the dport
+ was enumerated in RCH mode, a CXL 1.1 error is injected, otherwise
+ a CXL 2.0 error is injected.

Documentation/ABI/testing/sysfs-bus-cxl

@@ -552,3 +552,37 @@ Description:
  attribute is only visible for devices supporting the
  capability. The retrieved errors are logged as kernel
  events when cxl_poison event tracing is enabled.
+
+
+What: /sys/bus/cxl/devices/regionZ/accessY/read_bandwidth
+ /sys/bus/cxl/devices/regionZ/accessY/write_banwidth
+Date: Jan, 2024
+KernelVersion: v6.9
+Contact: [email protected]
+Description:
+ (RO) The aggregated read or write bandwidth of the region. The
+ number is the accumulated read or write bandwidth of all CXL memory
+ devices that contributes to the region in MB/s. It is
+ identical data that should appear in
+ /sys/devices/system/node/nodeX/accessY/initiators/read_bandwidth or
+ /sys/devices/system/node/nodeX/accessY/initiators/write_bandwidth.
+ See Documentation/ABI/stable/sysfs-devices-node. access0 provides
+ the number to the closest initiator and access1 provides the
+ number to the closest CPU.
+
+
+What: /sys/bus/cxl/devices/regionZ/accessY/read_latency
+ /sys/bus/cxl/devices/regionZ/accessY/write_latency
+Date: Jan, 2024
+KernelVersion: v6.9
+Contact: [email protected]
+Description:
+ (RO) The read or write latency of the region. The number is
+ the worst read or write latency of all CXL memory devices that
+ contributes to the region in nanoseconds. It is identical data
+ that should appear in
+ /sys/devices/system/node/nodeX/accessY/initiators/read_latency or
+ /sys/devices/system/node/nodeX/accessY/initiators/write_latency.
+ See Documentation/ABI/stable/sysfs-devices-node. access0 provides
+ the number to the closest initiator and access1 provides the
+ number to the closest CPU.

Documentation/firmware-guide/acpi/apei/einj.rst

@@ -32,6 +32,10 @@ configuration::
  CONFIG_ACPI_APEI
  CONFIG_ACPI_APEI_EINJ
 
+...and to (optionally) enable CXL protocol error injection set::
+
+ CONFIG_ACPI_APEI_EINJ_CXL
+
 The EINJ user interface is in <debugfs mount point>/apei/einj.
 
 The following files belong to it:
@@ -118,6 +122,24 @@ The following files belong to it:
  this actually works depends on what operations the BIOS actually
  includes in the trigger phase.
 
+CXL error types are supported from ACPI 6.5 onwards (given a CXL port
+is present). The EINJ user interface for CXL error types is at
+<debugfs mount point>/cxl. The following files belong to it:
+
+- einj_types:
+
+ Provides the same functionality as available_error_types above, but
+ for CXL error types
+
+- $dport_dev/einj_inject:
+
+ Injects a CXL error type into the CXL port represented by $dport_dev,
+ where $dport_dev is the name of the CXL port (usually a PCIe device name).
+ Error injections targeting a CXL 2.0+ port can use the legacy interface
+ under <debugfs mount point>/apei/einj, while CXL 1.1/1.0 port injections
+ must use this file.
+
+
 BIOS versions based on the ACPI 4.0 specification have limited options
 in controlling where the errors are injected. Your BIOS may support an
 extension (enabled with the param_extension=1 module parameter, or boot
@@ -181,6 +203,18 @@ You should see something like this in dmesg::
  [22715.834759] EDAC sbridge MC3: PROCESSOR 0:306e7 TIME 1422553404 SOCKET 0 APIC 0
  [22716.616173] EDAC MC3: 1 CE memory read error on CPU_SrcID#0_Channel#0_DIMM#0 (channel:0 slot:0 page:0x12345 offset:0x0 grain:32 syndrome:0x0 - area:DRAM err_code:0001:0090 socket:0 channel_mask:1 rank:0)
 
+A CXL error injection example with $dport_dev=0000:e0:01.1::
+
+ # cd /sys/kernel/debug/cxl/
+ # ls
+ 0000:e0:01.1 0000:0c:00.0
+ # cat einj_types # See which errors can be injected
+ 0x00008000 CXL.mem Protocol Correctable
+ 0x00010000 CXL.mem Protocol Uncorrectable non-fatal
+ 0x00020000 CXL.mem Protocol Uncorrectable fatal
+ # cd 0000:e0:01.1 # Navigate to dport to inject into
+ # echo 0x8000 > einj_inject # Inject error
+
 Special notes for injection into SGX enclaves:
 
 There may be a separate BIOS setup option to enable SGX injection.

MAINTAINERS

@@ -5321,6 +5321,7 @@ M: Dan Williams <[email protected]>
 L: [email protected]
 S: Maintained
 F: drivers/cxl/
+F: include/linux/cxl-einj.h
 F: include/linux/cxl-event.h
 F: include/uapi/linux/cxl_mem.h
 F: tools/testing/cxl/

drivers/acpi/apei/Kconfig

@@ -60,6 +60,19 @@ config ACPI_APEI_EINJ
  mainly used for debugging and testing the other parts of
  APEI and some other RAS features.
 
+config ACPI_APEI_EINJ_CXL
+ bool "CXL Error INJection Support"
+ default ACPI_APEI_EINJ
+ depends on ACPI_APEI_EINJ
+ depends on CXL_BUS && CXL_BUS <= ACPI_APEI_EINJ
+ help
+ Support for CXL protocol Error INJection through debugfs/cxl.
+ Availability and which errors are supported is dependent on
+ the host platform. Look to ACPI v6.5 section 18.6.4 and kernel
+ EINJ documentation for more information.
+
+ If unsure say 'n'
+
 config ACPI_APEI_ERST_DEBUG
  tristate "APEI Error Record Serialization Table (ERST) Debug Support"
  depends on ACPI_APEI

drivers/acpi/apei/Makefile

@@ -2,6 +2,8 @@
 obj-$(CONFIG_ACPI_APEI) += apei.o
 obj-$(CONFIG_ACPI_APEI_GHES) += ghes.o
 obj-$(CONFIG_ACPI_APEI_EINJ) += einj.o
+einj-y := einj-core.o
+einj-$(CONFIG_ACPI_APEI_EINJ_CXL) += einj-cxl.o
 obj-$(CONFIG_ACPI_APEI_ERST_DEBUG) += erst-dbg.o
 
 apei-y := apei-base.o hest.o erst.o bert.o

drivers/acpi/apei/apei-internal.h

@@ -130,4 +130,22 @@ static inline u32 cper_estatus_len(struct acpi_hest_generic_status *estatus)
 }
 
 int apei_osc_setup(void);
+
+int einj_get_available_error_type(u32 *type);
+int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, u64 param3,
+ u64 param4);
+int einj_cxl_rch_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
+ u64 param3, u64 param4);
+bool einj_is_cxl_error_type(u64 type);
+int einj_validate_error_type(u64 type);
+
+#ifndef ACPI_EINJ_CXL_CACHE_CORRECTABLE
+#define ACPI_EINJ_CXL_CACHE_CORRECTABLE BIT(12)
+#define ACPI_EINJ_CXL_CACHE_UNCORRECTABLE BIT(13)
+#define ACPI_EINJ_CXL_CACHE_FATAL BIT(14)
+#define ACPI_EINJ_CXL_MEM_CORRECTABLE BIT(15)
+#define ACPI_EINJ_CXL_MEM_UNCORRECTABLE BIT(16)
+#define ACPI_EINJ_CXL_MEM_FATAL BIT(17)
+#endif
+
 #endif