[PATCH v6 0/6] cxl: Add CXL type2 accelerator support for cxl_test

[PATCH v6 0/6] cxl: Add CXL type2 accelerator support for cxl_test

[Dave Jiang]

v6 rebases against v7.2-rc1 and sits on top of the the immutable branch [1]
for type 2.

See individual patches for changes from previous version.
Fixed up sashiko reported issues.

Series adds a 'type2_test' module parameter where it setup a mock type2
hierarchy with a mock type2 accelerator device directly under a root
port that has an auto region setup.

It also includes a CXL fix that was encountered when running tests with
the new code.

[
  {
    "memdevs":[
      {
        "memdev":"mem0",
        "ram_size":536870912,
        "ram_qos_class":42,
        "host":"cxl_type2_accel.0",
        "poison_injectable":false
      }
    ]
  },
  {
    "regions":[
      {
        "region":"region0",
        "resource":70300293136384,
        "size":536870912,
        "type":"ram",
        "interleave_ways":1,
        "interleave_granularity":4096,
        "decode_state":"commit"
      }
    ]
  }
]

    "root decoders":[
      {
        "decoder":"decoder0.0",
        "resource":70300293136384,
        "size":1073741824,
        "interleave_ways":1,
        "accelmem_capable":true,
        "qos_class":42,
        "nr_targets":1
      },

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git/log/?h=for-7.3/cxl-type2-support

Dave Jiang (6):
  cxl/test: Add test for module parameters
  cxl/test: Add type2 support for mock CFMWS0
  cxl/test: Refactor platform device enumerations
  cxl/test: Add hierarchy enumeration support for type2 device
  cxl/test: Fixup hdm init for auto region to support type2
  cxl/test: Add cxl_test accelerator driver

 tools/testing/cxl/test/Kbuild      |   2 +
 tools/testing/cxl/test/accel.c     |  66 +++
 tools/testing/cxl/test/cxl.c       | 820 ++++++++++++++++++++++-------
 tools/testing/cxl/test/hmem_test.c |   3 +-
 tools/testing/cxl/test/mock.h      |   2 +
 5 files changed, 695 insertions(+), 198 deletions(-)
 create mode 100644 tools/testing/cxl/test/accel.c


base-commit: 96ddf1af34f5f9e29891a5bfb7a18dd0a5bab9d6
-- 
2.54.0

[PATCH v6 1/6] cxl/test: Add test for module parameters

[Dave Jiang]

Add a test for module paraters during module init to make sure that
only one is activated.

Suggested-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v6:
- rebased against v7.2-rc1
---
 tools/testing/cxl/test/cxl.c       | 20 ++++++++++++++++++++
 tools/testing/cxl/test/hmem_test.c |  3 ++-
 tools/testing/cxl/test/mock.h      |  2 ++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index ef92dd35e030..198a128181b9 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -1827,11 +1827,31 @@ static struct attribute *cxl_acpi_attrs[] = {
 };
 ATTRIBUTE_GROUPS(cxl_acpi);
 
+static bool __init have_multiple_modparms(void)
+{
+	int count = 0;
+
+	if (interleave_arithmetic)
+		count++;
+	if (extended_linear_cache)
+		count++;
+	if (fail_autoassemble)
+		count++;
+	if (hmem_test)
+		count++;
+
+	return count > 1;
+}
+
 static __init int cxl_test_init(void)
 {
 	int rc, i;
 	struct range mappable;
 
+	/* Enforce a single module param active at a time */
+	if (have_multiple_modparms())
+		return -EINVAL;
+
 	if (!IS_ALIGNED(mock_auto_region_size, PMD_SIZE)) {
 		pr_err_once("mock_auto_region_size %d must be PMD-aligned\n",
 			    mock_auto_region_size);
diff --git a/tools/testing/cxl/test/hmem_test.c b/tools/testing/cxl/test/hmem_test.c
index 3a1a089e1721..0fa00f7e16db 100644
--- a/tools/testing/cxl/test/hmem_test.c
+++ b/tools/testing/cxl/test/hmem_test.c
@@ -3,8 +3,9 @@
 #include <linux/moduleparam.h>
 #include <linux/workqueue.h>
 #include "../../../drivers/dax/bus.h"
+#include "mock.h"
 
-static bool hmem_test;
+bool hmem_test;
 
 static void hmem_test_work(struct work_struct *work)
 {
diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
index 4f57dc80ae7d..846d7c5d6eaa 100644
--- a/tools/testing/cxl/test/mock.h
+++ b/tools/testing/cxl/test/mock.h
@@ -5,6 +5,8 @@
 #include <linux/dax.h>
 #include <cxl.h>
 
+extern bool hmem_test;
+
 struct cxl_mock_ops {
 	struct list_head list;
 	bool (*is_mock_adev)(struct acpi_device *dev);
-- 
2.54.0

[PATCH v6 2/6] cxl/test: Add type2 support for mock CFMWS0

[Dave Jiang]

Add a module parameter 'type2_test' for triggering type2 test support
in cxl_test. Setup the CFMWS0 configuration to be type2 when 'type2_test'
is set.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v6:
- Rebased against v7.2-rc1
---
 tools/testing/cxl/test/cxl.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 198a128181b9..32964420e470 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -17,6 +17,7 @@
 static int interleave_arithmetic;
 static bool extended_linear_cache;
 static bool fail_autoassemble;
+static bool type2_test;
 
 #define FAKE_QTG_ID	42
 
@@ -384,6 +385,19 @@ static struct {
 	},
 };
 
+static struct acpi_cedt_cfmws type2_cfmws0 = {
+	.header = {
+		.type = ACPI_CEDT_TYPE_CFMWS,
+		.length = sizeof(mock_cedt.cfmws0),
+	},
+	.interleave_ways = 0,
+	.granularity = 4,
+	.restrictions = ACPI_CEDT_CFMWS_RESTRICT_DEVMEM |
+			ACPI_CEDT_CFMWS_RESTRICT_VOLATILE,
+	.qtg_id = FAKE_QTG_ID,
+	.window_size = SZ_256M * 4,
+};
+
 struct acpi_cedt_cfmws *mock_cfmws[] = {
 	[0] = &mock_cedt.cfmws0.cfmws,
 	[1] = &mock_cedt.cfmws1.cfmws,
@@ -476,6 +490,11 @@ static void cfmws_elc_update(struct acpi_cedt_cfmws *window, int index)
 	window->window_size = mock_auto_region_size * 2;
 }
 
+static void update_type2_cfmws(void)
+{
+	memcpy(&mock_cedt.cfmws0.cfmws, &type2_cfmws0, sizeof(type2_cfmws0));
+}
+
 static int populate_cedt(void)
 {
 	struct cxl_mock_res *res;
@@ -497,11 +516,15 @@ static int populate_cedt(void)
 		chbs->length = size;
 	}
 
+	if (type2_test)
+		update_type2_cfmws();
+
 	for (i = cfmws_start; i <= cfmws_end; i++) {
 		struct acpi_cedt_cfmws *window = mock_cfmws[i];
 		int align = SZ_256M;
 
-		cfmws_elc_update(window, i);
+		if (i == 0 && !type2_test)
+			cfmws_elc_update(window, i);
 		if (window->restrictions & ACPI_CEDT_CFMWS_RESTRICT_VOLATILE)
 			align = max_t(int, SZ_256M, PMD_SIZE);
 		res = alloc_mock_res(window->window_size, align);
@@ -1839,6 +1862,8 @@ static bool __init have_multiple_modparms(void)
 		count++;
 	if (hmem_test)
 		count++;
+	if (type2_test)
+		count++;
 
 	return count > 1;
 }
@@ -2069,6 +2094,8 @@ module_param(extended_linear_cache, bool, 0444);
 MODULE_PARM_DESC(extended_linear_cache, "Enable extended linear cache support");
 module_param(fail_autoassemble, bool, 0444);
 MODULE_PARM_DESC(fail_autoassemble, "Simulate missing member of an auto-region");
+module_param(type2_test, bool, 0444);
+MODULE_PARM_DESC(type2_test, "Enable type 2 support testing");
 module_init(cxl_test_init);
 module_exit(cxl_test_exit);
 MODULE_LICENSE("GPL v2");
-- 
2.54.0

[PATCH v6 3/6] cxl/test: Refactor platform device enumerations

[Dave Jiang]

Split all the host bridges, rootports, upstream and downstream ports
enumerations to separate helper functions. This should make adding
type2 hierarchy easier later on.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 tools/testing/cxl/test/cxl.c | 312 ++++++++++++++++++++++++-----------
 1 file changed, 214 insertions(+), 98 deletions(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 32964420e470..8abe066080bc 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -1868,10 +1868,204 @@ static bool __init have_multiple_modparms(void)
 	return count > 1;
 }
 
+static void host_bridges_remove(void)
+{
+	int i;
+
+	for (i = ARRAY_SIZE(cxl_host_bridge) - 1; i >= 0; i--) {
+		struct platform_device *pdev = cxl_host_bridge[i];
+
+		if (!pdev)
+			continue;
+
+		sysfs_remove_link(&pdev->dev.kobj, "physical_node");
+		platform_device_unregister(cxl_host_bridge[i]);
+	}
+}
+
+static int host_bridges_populate(void)
+{
+	int rc = 0;
+
+	for (int i = 0; i < ARRAY_SIZE(cxl_host_bridge); i++) {
+		struct acpi_device *adev = &host_bridge[i];
+		struct platform_device *pdev;
+
+		pdev = platform_device_alloc("cxl_host_bridge", i);
+		if (!pdev) {
+			rc = -ENOMEM;
+			goto err_bridge;
+		}
+
+		mock_companion(adev, &pdev->dev);
+		rc = cxl_mock_platform_device_add(pdev, &cxl_host_bridge[i]);
+		if (rc)
+			goto err_bridge;
+
+		mock_pci_bus[i].bridge = &pdev->dev;
+		rc = sysfs_create_link(&pdev->dev.kobj, &pdev->dev.kobj,
+				       "physical_node");
+		if (rc)
+			goto err_bridge;
+	}
+
+	return 0;
+
+err_bridge:
+	host_bridges_remove();
+	return rc;
+}
+
+static void cxl_rootports_remove(void)
+{
+	for (int i = ARRAY_SIZE(cxl_root_port) - 1; i >= 0; i--) {
+		struct platform_device *pdev = cxl_root_port[i];
+
+		if (!pdev)
+			continue;
+
+		platform_device_unregister(pdev);
+	}
+}
+
+static int cxl_rootports_populate(void)
+{
+	int rc = 0;
+
+	for (int i = 0; i < ARRAY_SIZE(cxl_root_port); i++) {
+		struct platform_device *bridge =
+			cxl_host_bridge[i % ARRAY_SIZE(cxl_host_bridge)];
+		struct platform_device *pdev;
+
+		pdev = platform_device_alloc("cxl_root_port", i);
+		if (!pdev) {
+			rc = -ENOMEM;
+			goto err_port;
+		}
+
+		pdev->dev.parent = &bridge->dev;
+
+		rc = cxl_mock_platform_device_add(pdev, &cxl_root_port[i]);
+		if (rc)
+			goto err_port;
+	}
+
+	return 0;
+
+err_port:
+	cxl_rootports_remove();
+	return rc;
+}
+
+static void cxl_usps_remove(void)
+{
+	for (int i = ARRAY_SIZE(cxl_switch_uport) - 1; i >= 0; i--) {
+		struct platform_device *pdev = cxl_switch_uport[i];
+
+		if (!pdev)
+			continue;
+
+		platform_device_unregister(cxl_switch_uport[i]);
+	}
+}
+
+static int cxl_usps_populate(void)
+{
+	int rc = 0;
+
+	for (int i = 0; i < ARRAY_SIZE(cxl_switch_uport); i++) {
+		struct platform_device *root_port = cxl_root_port[i];
+		struct platform_device *pdev;
+
+		pdev = platform_device_alloc("cxl_switch_uport", i);
+		if (!pdev) {
+			rc = -ENOMEM;
+			goto err_uport;
+		}
+
+		pdev->dev.parent = &root_port->dev;
+
+		rc = cxl_mock_platform_device_add(pdev, &cxl_switch_uport[i]);
+		if (rc)
+			goto err_uport;
+	}
+
+	return 0;
+
+err_uport:
+	cxl_usps_remove();
+	return rc;
+}
+
+static void cxl_dsps_remove(void)
+{
+	for (int i = ARRAY_SIZE(cxl_switch_dport) - 1; i >= 0; i--) {
+		struct platform_device *pdev = cxl_switch_dport[i];
+
+		if (!pdev)
+			continue;
+
+		platform_device_unregister(cxl_switch_dport[i]);
+	}
+}
+
+
+static int cxl_dsps_populate(void)
+{
+	int rc = 0;
+
+	for (int i = 0; i < ARRAY_SIZE(cxl_switch_dport); i++) {
+		struct platform_device *uport =
+			cxl_switch_uport[i % ARRAY_SIZE(cxl_switch_uport)];
+		struct platform_device *pdev;
+
+		pdev = platform_device_alloc("cxl_switch_dport", i);
+		if (!pdev) {
+			rc = -ENOMEM;
+			goto err_dport;
+		}
+		pdev->dev.parent = &uport->dev;
+
+		rc = cxl_mock_platform_device_add(pdev, &cxl_switch_dport[i]);
+		if (rc)
+			goto err_dport;
+	}
+
+	return 0;
+
+err_dport:
+	cxl_dsps_remove();
+	return rc;
+}
+
+static void cxl_switches_remove(void)
+{
+	cxl_dsps_remove();
+	cxl_usps_remove();
+}
+
+static int cxl_switches_populate(void)
+{
+	int rc;
+
+	BUILD_BUG_ON(ARRAY_SIZE(cxl_switch_uport) != ARRAY_SIZE(cxl_root_port));
+	rc = cxl_usps_populate();
+	if (rc)
+		return rc;
+
+	rc = cxl_dsps_populate();
+	if (rc) {
+		cxl_usps_remove();
+		return rc;
+	}
+
+	return 0;
+}
+
 static __init int cxl_test_init(void)
 {
-	int rc, i;
 	struct range mappable;
+	int rc;
 
 	/* Enforce a single module param active at a time */
 	if (have_multiple_modparms())
@@ -1917,74 +2111,21 @@ static __init int cxl_test_init(void)
 	if (rc)
 		goto err_populate;
 
-	for (i = 0; i < ARRAY_SIZE(cxl_host_bridge); i++) {
-		struct acpi_device *adev = &host_bridge[i];
-		struct platform_device *pdev;
+	rc = host_bridges_populate();
+	if (rc)
+		goto err_populate;
 
-		pdev = platform_device_alloc("cxl_host_bridge", i);
-		if (!pdev)
-			goto err_bridge;
+	rc = cxl_rootports_populate();
+	if (rc)
+		goto err_host_bridges;
 
-		mock_companion(adev, &pdev->dev);
-		rc = cxl_mock_platform_device_add(pdev, &cxl_host_bridge[i]);
-		if (rc)
-			goto err_bridge;
-
-		mock_pci_bus[i].bridge = &pdev->dev;
-		rc = sysfs_create_link(&pdev->dev.kobj, &pdev->dev.kobj,
-				       "physical_node");
-		if (rc)
-			goto err_bridge;
-	}
-
-	for (i = 0; i < ARRAY_SIZE(cxl_root_port); i++) {
-		struct platform_device *bridge =
-			cxl_host_bridge[i % ARRAY_SIZE(cxl_host_bridge)];
-		struct platform_device *pdev;
-
-		pdev = platform_device_alloc("cxl_root_port", i);
-		if (!pdev)
-			goto err_port;
-		pdev->dev.parent = &bridge->dev;
-
-		rc = cxl_mock_platform_device_add(pdev, &cxl_root_port[i]);
-		if (rc)
-			goto err_port;
-	}
-
-	BUILD_BUG_ON(ARRAY_SIZE(cxl_switch_uport) != ARRAY_SIZE(cxl_root_port));
-	for (i = 0; i < ARRAY_SIZE(cxl_switch_uport); i++) {
-		struct platform_device *root_port = cxl_root_port[i];
-		struct platform_device *pdev;
-
-		pdev = platform_device_alloc("cxl_switch_uport", i);
-		if (!pdev)
-			goto err_uport;
-		pdev->dev.parent = &root_port->dev;
-
-		rc = cxl_mock_platform_device_add(pdev, &cxl_switch_uport[i]);
-		if (rc)
-			goto err_uport;
-	}
-
-	for (i = 0; i < ARRAY_SIZE(cxl_switch_dport); i++) {
-		struct platform_device *uport =
-			cxl_switch_uport[i % ARRAY_SIZE(cxl_switch_uport)];
-		struct platform_device *pdev;
-
-		pdev = platform_device_alloc("cxl_switch_dport", i);
-		if (!pdev)
-			goto err_dport;
-		pdev->dev.parent = &uport->dev;
-
-		rc = cxl_mock_platform_device_add(pdev, &cxl_switch_dport[i]);
-		if (rc)
-			goto err_dport;
-	}
+	rc = cxl_switches_populate();
+	if (rc)
+		goto err_root_ports;
 
 	rc = cxl_single_topo_init();
 	if (rc)
-		goto err_dport;
+		goto err_switches;
 
 	rc = cxl_rch_topo_init();
 	if (rc)
@@ -2020,24 +2161,12 @@ static __init int cxl_test_init(void)
 	cxl_rch_topo_exit();
 err_single:
 	cxl_single_topo_exit();
-err_dport:
-	for (i = ARRAY_SIZE(cxl_switch_dport) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_switch_dport[i]);
-err_uport:
-	for (i = ARRAY_SIZE(cxl_switch_uport) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_switch_uport[i]);
-err_port:
-	for (i = ARRAY_SIZE(cxl_root_port) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_root_port[i]);
-err_bridge:
-	for (i = ARRAY_SIZE(cxl_host_bridge) - 1; i >= 0; i--) {
-		struct platform_device *pdev = cxl_host_bridge[i];
-
-		if (!pdev)
-			continue;
-		sysfs_remove_link(&pdev->dev.kobj, "physical_node");
-		platform_device_unregister(cxl_host_bridge[i]);
-	}
+err_switches:
+	cxl_switches_remove();
+err_root_ports:
+	cxl_rootports_remove();
+err_host_bridges:
+	host_bridges_remove();
 err_populate:
 	depopulate_all_mock_resources();
 err_gen_pool_add:
@@ -2060,27 +2189,14 @@ static void free_decoder_registry(void)
 
 static __exit void cxl_test_exit(void)
 {
-	int i;
-
 	hmem_test_exit();
 	cxl_mem_exit();
 	platform_device_unregister(cxl_acpi);
 	cxl_rch_topo_exit();
 	cxl_single_topo_exit();
-	for (i = ARRAY_SIZE(cxl_switch_dport) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_switch_dport[i]);
-	for (i = ARRAY_SIZE(cxl_switch_uport) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_switch_uport[i]);
-	for (i = ARRAY_SIZE(cxl_root_port) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_root_port[i]);
-	for (i = ARRAY_SIZE(cxl_host_bridge) - 1; i >= 0; i--) {
-		struct platform_device *pdev = cxl_host_bridge[i];
-
-		if (!pdev)
-			continue;
-		sysfs_remove_link(&pdev->dev.kobj, "physical_node");
-		platform_device_unregister(cxl_host_bridge[i]);
-	}
+	cxl_switches_remove();
+	cxl_rootports_remove();
+	host_bridges_remove();
 	depopulate_all_mock_resources();
 	gen_pool_destroy(cxl_mock_pool);
 	unregister_cxl_mock_ops(&cxl_mock_ops);
-- 
2.54.0

[PATCH v6 4/6] cxl/test: Add hierarchy enumeration support for type2 device

[Dave Jiang]

Add enumeration of type2 device hierarchy in cxl-test. The type2 device
is setup to be directly attached to a root port instead of rp -> switch
-> device that type3 hierarchy is setup..

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 tools/testing/cxl/test/cxl.c | 240 ++++++++++++++++++++++++++++-------
 1 file changed, 193 insertions(+), 47 deletions(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 8abe066080bc..1eac06ad4660 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -28,6 +28,7 @@ static bool type2_test;
 #define NR_CXL_SWITCH_PORTS 2
 #define NR_CXL_PORT_DECODERS 8
 #define NR_BRIDGES (NR_CXL_HOST_BRIDGES + NR_CXL_SINGLE_HOST + NR_CXL_RCH)
+#define NR_CXL_TYPE2_ACCEL 1
 
 #define MOCK_AUTO_REGION_SIZE_DEFAULT SZ_512M
 static int mock_auto_region_size = MOCK_AUTO_REGION_SIZE_DEFAULT;
@@ -1747,19 +1748,93 @@ static void cxl_single_topo_exit(void)
 	}
 }
 
+static void cxl_type3_mem_exit(void)
+{
+	struct platform_device *pdev;
+	int i;
+
+	for (i = ARRAY_SIZE(cxl_rcd) - 1; i >= 0; i--) {
+		pdev = cxl_rcd[i];
+		if (!pdev)
+			continue;
+		platform_device_unregister(cxl_rcd[i]);
+	}
+
+	for (i = ARRAY_SIZE(cxl_mem_single) - 1; i >= 0; i--) {
+		pdev = cxl_mem_single[i];
+		if (!pdev)
+			continue;
+		platform_device_unregister(cxl_mem_single[i]);
+	}
+
+	for (i = ARRAY_SIZE(cxl_mem) - 1; i >= 0; i--) {
+		pdev = cxl_mem[i];
+		if (!pdev)
+			continue;
+		platform_device_unregister(pdev);
+	}
+}
+
+static void cxl_type2_mem_exit(void)
+{
+	for (int i = NR_CXL_TYPE2_ACCEL - 1; i >= 0; i--) {
+		struct platform_device *pdev = cxl_mem[i];
+
+		if (!pdev)
+			continue;
+		platform_device_unregister(pdev);
+	}
+}
+
 static void cxl_mem_exit(void)
 {
-	int i;
-
-	for (i = ARRAY_SIZE(cxl_rcd) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_rcd[i]);
-	for (i = ARRAY_SIZE(cxl_mem_single) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_mem_single[i]);
-	for (i = ARRAY_SIZE(cxl_mem) - 1; i >= 0; i--)
-		platform_device_unregister(cxl_mem[i]);
+	if (type2_test) {
+		cxl_type2_mem_exit();
+		return;
+	}
+
+	cxl_type3_mem_exit();
+}
+
+static int cxl_type2_mem_init(void)
+{
+	int i, rc;
+
+	for (i = 0; i < NR_CXL_TYPE2_ACCEL; i++) {
+		struct platform_device *dport = cxl_root_port[i];
+		struct platform_device *pdev;
+
+		pdev = platform_device_alloc("cxl_type2_accel", i);
+		if (!pdev) {
+			rc = -ENOMEM;
+			goto err_mem;
+		}
+		pdev->dev.parent = &dport->dev;
+		set_dev_node(&pdev->dev, i % 2);
+
+		rc = platform_device_add(pdev);
+		if (rc) {
+			rc = -ENOMEM;
+			platform_device_put(pdev);
+			goto err_mem;
+		}
+		cxl_mem[i] = pdev;
+	}
+
+	return 0;
+
+err_mem:
+	for (i = NR_CXL_TYPE2_ACCEL - 1; i >= 0; i--) {
+		struct platform_device *pdev = cxl_mem[i];
+
+		if (!pdev)
+			continue;
+		platform_device_unregister(pdev);
+	}
+	return rc;
 }
 
-static int cxl_mem_init(void)
+static int cxl_type3_mem_init(void)
 {
 	int i, rc;
 
@@ -1768,8 +1843,10 @@ static int cxl_mem_init(void)
 		struct platform_device *pdev;
 
 		pdev = platform_device_alloc("cxl_mem", i);
-		if (!pdev)
+		if (!pdev) {
+			rc = -ENOMEM;
 			goto err_mem;
+		}
 		pdev->dev.parent = &dport->dev;
 		set_dev_node(&pdev->dev, i % 2);
 
@@ -1783,8 +1860,10 @@ static int cxl_mem_init(void)
 		struct platform_device *pdev;
 
 		pdev = platform_device_alloc("cxl_mem", NR_MEM_MULTI + i);
-		if (!pdev)
+		if (!pdev) {
+			rc = -ENOMEM;
 			goto err_single;
+		}
 		pdev->dev.parent = &dport->dev;
 		set_dev_node(&pdev->dev, i % 2);
 
@@ -1799,8 +1878,10 @@ static int cxl_mem_init(void)
 		struct platform_device *pdev;
 
 		pdev = platform_device_alloc("cxl_rcd", idx);
-		if (!pdev)
+		if (!pdev) {
+			rc = -ENOMEM;
 			goto err_rcd;
+		}
 		pdev->dev.parent = &rch->dev;
 		set_dev_node(&pdev->dev, i % 2);
 
@@ -1823,6 +1904,13 @@ static int cxl_mem_init(void)
 	return rc;
 }
 
+static int cxl_mem_init(void)
+{
+	if (type2_test)
+		return cxl_type2_mem_init();
+	return cxl_type3_mem_init();
+}
+
 static ssize_t
 decoder_reset_preserve_registry_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
@@ -2062,6 +2150,92 @@ static int cxl_switches_populate(void)
 	return 0;
 }
 
+static void cxl_type2_topo_exit(void)
+{
+	cxl_rootports_remove();
+	host_bridges_remove();
+}
+
+static int cxl_type2_topo_init(void)
+{
+	int rc;
+
+	rc = host_bridges_populate();
+	if (rc)
+		return rc;
+
+	rc = cxl_rootports_populate();
+	if (rc) {
+		host_bridges_remove();
+		return rc;
+	}
+
+	return 0;
+}
+
+static void cxl_type3_topo_exit(void)
+{
+	cxl_rch_topo_exit();
+	cxl_single_topo_exit();
+	cxl_switches_remove();
+	cxl_rootports_remove();
+	host_bridges_remove();
+}
+
+static int cxl_type3_topo_init(void)
+{
+	int rc;
+
+	rc = host_bridges_populate();
+	if (rc)
+		return rc;
+
+	rc = cxl_rootports_populate();
+	if (rc)
+		goto err_host_bridges;
+
+	rc = cxl_switches_populate();
+	if (rc)
+		goto err_root_ports;
+
+	rc = cxl_single_topo_init();
+	if (rc)
+		goto err_switches;
+
+	rc = cxl_rch_topo_init();
+	if (rc)
+		goto err_single;
+
+	return 0;
+
+err_single:
+	cxl_single_topo_exit();
+err_switches:
+	cxl_switches_remove();
+err_root_ports:
+	cxl_rootports_remove();
+err_host_bridges:
+	host_bridges_remove();
+	return rc;
+}
+
+static void cxl_topo_exit(void)
+{
+	if (type2_test) {
+		cxl_type2_topo_exit();
+		return;
+	}
+
+	cxl_type3_topo_exit();
+}
+
+static int cxl_topo_init(void)
+{
+	if (type2_test)
+		return cxl_type2_topo_init();
+	return cxl_type3_topo_init();
+}
+
 static __init int cxl_test_init(void)
 {
 	struct range mappable;
@@ -2111,29 +2285,13 @@ static __init int cxl_test_init(void)
 	if (rc)
 		goto err_populate;
 
-	rc = host_bridges_populate();
+	rc = cxl_topo_init();
 	if (rc)
 		goto err_populate;
 
-	rc = cxl_rootports_populate();
-	if (rc)
-		goto err_host_bridges;
-
-	rc = cxl_switches_populate();
-	if (rc)
-		goto err_root_ports;
-
-	rc = cxl_single_topo_init();
-	if (rc)
-		goto err_switches;
-
-	rc = cxl_rch_topo_init();
-	if (rc)
-		goto err_single;
-
 	cxl_acpi = platform_device_alloc("cxl_acpi", 0);
 	if (!cxl_acpi)
-		goto err_rch;
+		goto err_topo;
 
 	mock_companion(&acpi0017_mock, &cxl_acpi->dev);
 	acpi0017_mock.dev.bus = &platform_bus_type;
@@ -2141,7 +2299,7 @@ static __init int cxl_test_init(void)
 
 	rc = cxl_mock_platform_device_add(cxl_acpi, NULL);
 	if (rc)
-		goto err_rch;
+		goto err_topo;
 
 	rc = cxl_mem_init();
 	if (rc)
@@ -2156,17 +2314,9 @@ static __init int cxl_test_init(void)
 err_mem:
 	cxl_mem_exit();
 err_root:
-	platform_device_unregister(cxl_acpi);
-err_rch:
-	cxl_rch_topo_exit();
-err_single:
-	cxl_single_topo_exit();
-err_switches:
-	cxl_switches_remove();
-err_root_ports:
-	cxl_rootports_remove();
-err_host_bridges:
-	host_bridges_remove();
+	platform_device_put(cxl_acpi);
+err_topo:
+	cxl_topo_exit();
 err_populate:
 	depopulate_all_mock_resources();
 err_gen_pool_add:
@@ -2192,11 +2342,7 @@ static __exit void cxl_test_exit(void)
 	hmem_test_exit();
 	cxl_mem_exit();
 	platform_device_unregister(cxl_acpi);
-	cxl_rch_topo_exit();
-	cxl_single_topo_exit();
-	cxl_switches_remove();
-	cxl_rootports_remove();
-	host_bridges_remove();
+	cxl_topo_exit();
 	depopulate_all_mock_resources();
 	gen_pool_destroy(cxl_mock_pool);
 	unregister_cxl_mock_ops(&cxl_mock_ops);
-- 
2.54.0

[PATCH v6 5/6] cxl/test: Fixup hdm init for auto region to support type2

[Dave Jiang]

Add support to setup initialization of decoders in order to support
type2 auto region.

Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 tools/testing/cxl/test/cxl.c | 255 +++++++++++++++++++++++++----------
 1 file changed, 186 insertions(+), 69 deletions(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 1eac06ad4660..910c8b9abc00 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -1084,74 +1084,26 @@ static int first_decoder(struct device *dev, const void *data)
 	return 0;
 }
 
-/*
- * Initialize a decoder during HDM enumeration.
- *
- * If a saved registry entry exists:
- *   - enabled decoders are restored from the saved programming
- *   - disabled decoders are initialized in a clean disabled state
- *
- * If no registry entry exists the decoder follows the normal mock
- * initialization path, including the special auto-region setup for
- * the first endpoints under host-bridge0.
- *
- * Returns true if decoder state was restored from the registry. In
- * that case the saved decode configuration (including target mapping)
- * has already been applied and the map_targets() is skipped.
- */
-static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
+enum cxld_init_type {
+	MOCK_DECODER_INIT_DEFAULT,
+	MOCK_DECODER_INIT_SAVED,
+	MOCK_DECODER_INIT_TYPE3_AUTO,
+	MOCK_DECODER_INIT_TYPE2_AUTO,
+};
+
+static enum cxld_init_type get_decoder_init_type(struct cxl_decoder *cxld,
+						 struct platform_device *pdev,
+						 bool hb0,
+						 struct cxl_test_decoder **td)
 {
-	struct acpi_cedt_cfmws *window = mock_cfmws[0];
-	struct platform_device *pdev = NULL;
-	struct cxl_endpoint_decoder *cxled;
-	struct cxl_switch_decoder *cxlsd;
-	struct cxl_port *port, *iter;
-	struct cxl_test_decoder *td;
-	struct cxl_memdev *cxlmd;
-	struct cxl_dport *dport;
-	struct device *dev;
-	bool hb0 = false;
-	u64 base;
-	int i;
+	struct cxl_test_decoder *found_td = cxld_registry_find(cxld);
 
-	if (is_endpoint_decoder(&cxld->dev)) {
-		cxled = to_cxl_endpoint_decoder(&cxld->dev);
-		cxlmd = cxled_to_memdev(cxled);
-		WARN_ON(!dev_is_platform(cxlmd->dev.parent));
-		pdev = to_platform_device(cxlmd->dev.parent);
-
-		/* check is endpoint is attach to host-bridge0 */
-		port = cxled_to_port(cxled);
-		do {
-			if (port->uport_dev == &cxl_host_bridge[0]->dev) {
-				hb0 = true;
-				break;
-			}
-			if (is_cxl_port(port->dev.parent))
-				port = to_cxl_port(port->dev.parent);
-			else
-				port = NULL;
-		} while (port);
-		port = cxled_to_port(cxled);
-	} else {
-		port = to_cxl_port(cxld->dev.parent);
+	if (found_td) {
+		*td = found_td;
+		return MOCK_DECODER_INIT_SAVED;
 	}
 
-	td = cxld_registry_find(cxld);
-	if (td) {
-		bool enabled;
-
-		if (is_switch_decoder(&cxld->dev))
-			enabled = td->cxlsd.cxld.flags & CXL_DECODER_F_ENABLE;
-		else
-			enabled = td->cxled.cxld.flags & CXL_DECODER_F_ENABLE;
-
-		if (enabled)
-			return !cxld_registry_restore(cxld, td);
-
-		init_disabled_mock_decoder(cxld);
-		return false;
-	}
+	*td = NULL;
 
 	/*
 	 * The first decoder on the first 2 devices on the first switch
@@ -1162,15 +1114,111 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
 	 * See 'cxl list -BMPu -m cxl_mem.0,cxl_mem.4'
 	 */
 	if (!is_endpoint_decoder(&cxld->dev) || !hb0 || pdev->id % 4 ||
-	    pdev->id > 4 || cxld->id > 0) {
-		default_mock_decoder(cxld);
-		return false;
-	}
+	    pdev->id > 4 || cxld->id > 0)
+		return MOCK_DECODER_INIT_DEFAULT;
+
+	return type2_test ? MOCK_DECODER_INIT_TYPE2_AUTO :
+			    MOCK_DECODER_INIT_TYPE3_AUTO;
+}
+
+static bool mock_decoder_handle_saved(struct cxl_decoder *cxld, struct cxl_test_decoder *td)
+{
+	bool enabled;
+
+	if (is_switch_decoder(&cxld->dev))
+		enabled = td->cxlsd.cxld.flags & CXL_DECODER_F_ENABLE;
+	else
+		enabled = td->cxled.cxld.flags & CXL_DECODER_F_ENABLE;
+
+	if (enabled)
+		return !cxld_registry_restore(cxld, td);
+
+	init_disabled_mock_decoder(cxld);
+	return false;
+}
+
+static void mock_init_hdm_type2_cxled(struct cxl_endpoint_decoder *cxled,
+				      struct cxl_port *port,
+				      struct platform_device *pdev)
+{
+	struct acpi_cedt_cfmws *window = mock_cfmws[0];
+	struct cxl_decoder *cxld = &cxled->cxld;
+	struct cxl_switch_decoder *cxlsd;
+	struct cxl_dport *dport;
+	struct cxl_port *root_port;
+	struct device *dev;
+	u64 base;
+
+	base = window->base_hpa;
+	cxld->hpa_range = (struct range) {
+		.start = base,
+		.end = base + mock_auto_region_size - 1,
+	};
+
+	cxld->interleave_ways = 1;
+	eig_to_granularity(window->granularity, &cxld->interleave_granularity);
+	cxld->target_type = CXL_DECODER_DEVMEM;
+	cxld->flags = CXL_DECODER_F_ENABLE;
+	cxled->state = CXL_DECODER_STATE_AUTO;
+	port->commit_end = cxld->id;
+	devm_cxl_dpa_reserve(cxled, 0,
+			     mock_auto_region_size / cxld->interleave_ways, 0);
+	cxld->commit = mock_decoder_commit;
+	cxld->reset = mock_decoder_reset;
+
+	WARN_ON_ONCE(!cxld_registry_new(cxld));
+	/*
+	 * Now that endpoint decoder is set up, walk up the hierarchy
+	 * and setup the root port decoder targeting @cxlmd.
+	 */
+	dport = port->parent_dport;
+	root_port = dport->port;
+	dev = device_find_child(&root_port->dev, NULL, first_decoder);
+	/*
+	 * Ancestor ports are guaranteed to be enumerated before
+	 * @port, and all ports have at least one decoder.
+	 */
+	if (WARN_ON(!dev))
+		return;
+
+	cxlsd = to_cxl_switch_decoder(dev);
+	cxlsd->target[0] = dport;
+	cxlsd->cxld.target_map[0] = dport->port_id;
+	cxld = &cxlsd->cxld;
+	cxld->target_type = CXL_DECODER_DEVMEM;
+	cxld->flags = CXL_DECODER_F_ENABLE;
+	root_port->commit_end = 0;
+	cxld->interleave_ways = 1;
+	cxld->interleave_granularity = 4096;
+	cxld->hpa_range = (struct range) {
+		.start = base,
+		.end = base + mock_auto_region_size - 1,
+	};
+	cxld->commit = mock_decoder_commit;
+	cxld->reset = mock_decoder_reset;
+
+	cxld_registry_update(cxld);
+	put_device(dev);
+}
+
+static void mock_init_hdm_type3_cxled(struct cxl_endpoint_decoder *cxled,
+				      struct cxl_port *port,
+				      struct platform_device *pdev,
+				      bool hb0)
+{
+	struct acpi_cedt_cfmws *window = mock_cfmws[0];
+	struct cxl_decoder *cxld = &cxled->cxld;
+	struct cxl_switch_decoder *cxlsd;
+	struct cxl_dport *dport;
+	struct cxl_port *iter;
+	struct device *dev;
+	u64 base;
+	int i;
 
 	/* Simulate missing cxl_mem.4 configuration */
 	if (hb0 && pdev->id == 4 && cxld->id == 0 && fail_autoassemble) {
 		default_mock_decoder(cxld);
-		return false;
+		return;
 	}
 
 	base = window->base_hpa;
@@ -1252,7 +1300,76 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
 		cxld_registry_update(cxld);
 		put_device(dev);
 	}
+}
 
+/*
+ * Initialize a decoder during HDM enumeration.
+ *
+ * If a saved registry entry exists:
+ *   - enabled decoders are restored from the saved programming
+ *   - disabled decoders are initialized in a clean disabled state
+ *
+ * If no registry entry exists the decoder follows the normal mock
+ * initialization path, including the special auto-region setup for
+ * the first endpoints under host-bridge0.
+ *
+ * Returns true if decoder state was restored from the registry. In
+ * that case the saved decode configuration (including target mapping)
+ * has already been applied and the map_targets() is skipped.
+ */
+static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
+{
+	struct cxl_endpoint_decoder *cxled = NULL;
+	struct platform_device *pdev = NULL;
+	struct cxl_test_decoder *td;
+	struct cxl_memdev *cxlmd;
+	struct cxl_port *port;
+	bool hb0 = false;
+
+	if (is_endpoint_decoder(&cxld->dev)) {
+		cxled = to_cxl_endpoint_decoder(&cxld->dev);
+		cxlmd = cxled_to_memdev(cxled);
+		WARN_ON(!dev_is_platform(cxlmd->dev.parent));
+		pdev = to_platform_device(cxlmd->dev.parent);
+
+		/* check is endpoint is attach to host-bridge0 */
+		port = cxled_to_port(cxled);
+		do {
+			if (port->uport_dev == &cxl_host_bridge[0]->dev) {
+				hb0 = true;
+				break;
+			}
+			if (is_cxl_port(port->dev.parent))
+				port = to_cxl_port(port->dev.parent);
+			else
+				port = NULL;
+		} while (port);
+		port = cxled_to_port(cxled);
+	} else {
+		port = to_cxl_port(cxld->dev.parent);
+	}
+
+	switch (get_decoder_init_type(cxld, pdev, hb0, &td)) {
+	case MOCK_DECODER_INIT_SAVED:
+		if (WARN_ON(!td))
+			return false;
+		return mock_decoder_handle_saved(cxld, td);
+	case MOCK_DECODER_INIT_DEFAULT:
+		/*
+		 * The default path picks up all the decoders that are not
+		 * endpoint.
+		 */
+		default_mock_decoder(cxld);
+		return false;
+	case MOCK_DECODER_INIT_TYPE3_AUTO:
+		mock_init_hdm_type3_cxled(cxled, port, pdev, hb0);
+		return false;
+	case MOCK_DECODER_INIT_TYPE2_AUTO:
+		mock_init_hdm_type2_cxled(cxled, port, pdev);
+		return false;
+	default:
+		return false;
+	}
 	return false;
 }
 
-- 
2.54.0

[PATCH v6 6/6] cxl/test: Add cxl_test accelerator driver

[Dave Jiang]

Add a type2 accelerator mock driver for the platform device that
simulates a CXL type2 device. The driver exercises the same
minimal API calls that a real CXL type2 driver would utilize.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v6:
- drop extra init member in platform_device_id init. (Uwe)
---
 tools/testing/cxl/test/Kbuild  |  2 ++
 tools/testing/cxl/test/accel.c | 66 ++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 tools/testing/cxl/test/accel.c

diff --git a/tools/testing/cxl/test/Kbuild b/tools/testing/cxl/test/Kbuild
index c168e3c998a7..9a24ddc28488 100644
--- a/tools/testing/cxl/test/Kbuild
+++ b/tools/testing/cxl/test/Kbuild
@@ -5,10 +5,12 @@ obj-m += cxl_test.o
 obj-m += cxl_mock.o
 obj-m += cxl_mock_mem.o
 obj-m += cxl_translate.o
+obj-m += cxl_mock_accel.o
 
 cxl_test-y := cxl.o
 cxl_test-y += hmem_test.o
 cxl_mock-y := mock.o
 cxl_mock_mem-y := mem.o
+cxl_mock_accel-y := accel.o
 
 KBUILD_CFLAGS := $(filter-out -Wmissing-prototypes -Wmissing-declarations, $(KBUILD_CFLAGS))
diff --git a/tools/testing/cxl/test/accel.c b/tools/testing/cxl/test/accel.c
new file mode 100644
index 000000000000..8e6f4687ca02
--- /dev/null
+++ b/tools/testing/cxl/test/accel.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright(c) 2026 Intel Corporation. All rights reserved.
+
+#include <linux/platform_device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <cxl/mailbox.h>
+#include <cxlmem.h>
+
+struct mock_cxl_accel {
+	struct cxl_dev_state cxlds;
+	struct cxl_memdev *cxlmd;
+};
+
+static int cxl_mock_accel_probe(struct platform_device *pdev)
+{
+	struct mock_cxl_accel *cxl_accel;
+	struct device *dev = &pdev->dev;
+	struct cxl_dev_state *cxlds;
+	struct cxl_memdev *cxlmd;
+	struct range mock_range;
+	int rc;
+
+	cxl_accel = devm_cxl_dev_state_create(&pdev->dev, CXL_DEVTYPE_DEVMEM,
+					      pdev->id + 1, 0,
+					      struct mock_cxl_accel, cxlds,
+					      false);
+	if (!cxl_accel)
+		return -ENOMEM;
+
+	cxlds = &cxl_accel->cxlds;
+	cxlds->media_ready = true;
+	rc = cxl_set_capacity(cxlds, SZ_512M);
+	if (rc)
+		return rc;
+
+	cxlmd = devm_cxl_probe_mem(cxlds, &mock_range);
+	if (IS_ERR(cxlmd))
+		return PTR_ERR(cxlmd);
+	cxl_accel->cxlmd = cxlmd;
+
+	dev_dbg(dev, "Probed mock accelerator with range %pra\n", &mock_range);
+
+	return 0;
+}
+
+static const struct platform_device_id cxl_mock_accel_ids[] = {
+	{ .name = "cxl_type2_accel" },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, cxl_mock_accel_ids);
+
+static struct platform_driver cxl_mock_accel_driver = {
+	.probe = cxl_mock_accel_probe,
+	.id_table = cxl_mock_accel_ids,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+
+module_platform_driver(cxl_mock_accel_driver);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("cxl_test: accelerator device mock module");
+MODULE_IMPORT_NS("CXL");
-- 
2.54.0

Re: [PATCH v6 4/6] cxl/test: Add hierarchy enumeration support for type2 device

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The error path for cxl_test_init() incorrectly replaces platform_device_unregister() with platform_device_put() for cxl_acpi, leading to a resource leak and potential use-after-free.
--

commit 74917ddebbac04cd137d2f935b0132cdc7d979fe
Author: Dave Jiang <dave.jiang@intel.com>
cxl/test: Add hierarchy enumeration support for type2 device

This commit adds enumeration of type2 device hierarchy in cxl-test. The type2 
device is configured to be directly attached to a root port instead of the 
rp -> switch -> device setup used for type3 hierarchy.

> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 8abe066080bc8..1eac06ad46601 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c
[ ... ]
> @@ -2156,17 +2314,9 @@ static __init int cxl_test_init(void)
>  err_mem:
>  	cxl_mem_exit();
>  err_root:
> -	platform_device_unregister(cxl_acpi);
> -err_rch:
> -	cxl_rch_topo_exit();
> -err_single:
> -	cxl_single_topo_exit();
> -err_switches:
> -	cxl_switches_remove();
> -err_root_ports:
> -	cxl_rootports_remove();
> -err_host_bridges:
> -	host_bridges_remove();
> +	platform_device_put(cxl_acpi);

[Severity: High]
Does this error path properly tear down the device if cxl_mem_init() or
hmem_test_init() fails?

Since cxl_acpi was already successfully registered with the driver core via
cxl_mock_platform_device_add() earlier in cxl_test_init(), it seems
platform_device_unregister() should be used instead of platform_device_put().

Using platform_device_put() here only drops the initial allocation reference,
leaving the device actively linked in the platform bus and sysfs hierarchies.

Because the module unload upon initialization failure will free its memory,
could any subsequent access to the device's sysfs files dereference invalid
memory and cause a use-after-free?

> +err_topo:
> +	cxl_topo_exit();
>  err_populate:
>  	depopulate_all_mock_resources();
>  err_gen_pool_add:

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260629202720.3658117-1-dave.jiang@intel.com?part=4

Re: [PATCH v6 6/6] cxl/test: Add cxl_test accelerator driver

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The module calls an undefined function `cxl_set_capacity()`, resulting in a build failure.
--

commit 4857e7bc9c7f23612e9f8b197d31f99d7d824ef0
Author: Dave Jiang <dave.jiang@intel.com>

cxl/test: Add cxl_test accelerator driver

This commit adds a mock driver for a platform device that simulates a CXL 
type2 accelerator. It exercises the minimal API calls that a real CXL type2 
driver would use.

> diff --git a/tools/testing/cxl/test/accel.c b/tools/testing/cxl/test/accel.c
> new file mode 100644
> index 0000000000000..8e6f4687ca02a
> --- /dev/null
> +++ b/tools/testing/cxl/test/accel.c
[ ... ]
> +static int cxl_mock_accel_probe(struct platform_device *pdev)
> +{
[ ... ]
> +	cxlds = &cxl_accel->cxlds;
> +	cxlds->media_ready = true;
> +	rc = cxl_set_capacity(cxlds, SZ_512M);

[Severity: Low]
Does cxl_set_capacity() exist in the kernel tree? I am unable to locate a 
declaration or definition for this function, which seems like it would 
trigger a build failure during module compilation.

> +	if (rc)
> +		return rc;
> +
> +	cxlmd = devm_cxl_probe_mem(cxlds, &mock_range);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260629202720.3658117-1-dave.jiang@intel.com?part=6

Re: [PATCH v6 5/6] cxl/test: Fixup hdm init for auto region to support type2

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [Medium] mock_init_hdm_type2_cxled bypasses cxl_port_update_decoder_targets() and modifies the live decoder target array directly without the cxl_rwsem.region lock.
- [Medium] Missing return value check for devm_cxl_dpa_reserve().
- [Low] Unused parameter `pdev` in `mock_init_hdm_type2_cxled`.
--

commit 0f9c8e2fe22ac8d4fe6d8be6b13b11102337bb2b
Author: Dave Jiang <dave.jiang@intel.com>

cxl/test: Fixup hdm init for auto region to support type2

This commit adds support to set up the initialization of decoders
to support type 2 auto regions in the cxl test framework.

> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 1eac06ad46601..910c8b9abc003 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c

[ ... ]

> +static void mock_init_hdm_type2_cxled(struct cxl_endpoint_decoder *cxled,
> +				      struct cxl_port *port,
> +				      struct platform_device *pdev)

[Severity: Low]
This isn't a bug, but it looks like pdev is never evaluated or used in
this function. Is this parameter necessary?

> +{
> +	struct acpi_cedt_cfmws *window = mock_cfmws[0];
> +	struct cxl_decoder *cxld = &cxled->cxld;

[ ... ]

> +	cxld->target_type = CXL_DECODER_DEVMEM;
> +	cxld->flags = CXL_DECODER_F_ENABLE;
> +	cxled->state = CXL_DECODER_STATE_AUTO;
> +	port->commit_end = cxld->id;
> +	devm_cxl_dpa_reserve(cxled, 0,
> +			     mock_auto_region_size / cxld->interleave_ways, 0);

[Severity: Medium]
Does this code need to check the return value of devm_cxl_dpa_reserve()?

If this call fails with an error like -ENOMEM or -EBUSY, the mock framework
will silently proceed with an invalid or unreserved DPA state, which could
mask bugs or cause test crashes later on.

> +	cxld->commit = mock_decoder_commit;
> +	cxld->reset = mock_decoder_reset;
> +
> +	WARN_ON_ONCE(!cxld_registry_new(cxld));
> +	/*
> +	 * Now that endpoint decoder is set up, walk up the hierarchy
> +	 * and setup the root port decoder targeting @cxlmd.
> +	 */
> +	dport = port->parent_dport;
> +	root_port = dport->port;
> +	dev = device_find_child(&root_port->dev, NULL, first_decoder);
> +	/*
> +	 * Ancestor ports are guaranteed to be enumerated before
> +	 * @port, and all ports have at least one decoder.
> +	 */
> +	if (WARN_ON(!dev))
> +		return;
> +
> +	cxlsd = to_cxl_switch_decoder(dev);
> +	cxlsd->target[0] = dport;
> +	cxlsd->cxld.target_map[0] = dport->port_id;

[Severity: Medium]
Is it safe to directly assign to the live decoder target array here
without holding the cxl_rwsem.region lock for synchronization?

Bypassing cxl_port_update_decoder_targets() and modifying the decoder target
array directly creates a data race against concurrent sysfs readers like
target_list_show() that rely on this lock. Should this use
cxl_port_update_decoder_targets() instead?

> +	cxld = &cxlsd->cxld;
> +	cxld->target_type = CXL_DECODER_DEVMEM;
> +	cxld->flags = CXL_DECODER_F_ENABLE;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260629202720.3658117-1-dave.jiang@intel.com?part=5

Re: [PATCH v6 3/6] cxl/test: Refactor platform device enumerations

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Failure to assign an error code to `rc` (e.g., `-ENOMEM`) on device allocation failures in `cxl_test_init()`, `cxl_single_topo_init()`, and `cxl_rch_topo_init()`. This causes the functions to return `0` (success) or an uninitialized stack value on failure.
--

commit 49a38c246be39e985c66be86964ee186b899793d
Author: Dave Jiang <dave.jiang@intel.com>

cxl/test: Refactor platform device enumerations

Split all the host bridges, rootports, upstream and downstream ports
enumerations to separate helper functions. This should make adding
type2 hierarchy easier later on.

> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 32964420e470a..8abe066080bc8 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c
[ ... ]
> @@ -1868,62 +1868,34 @@ static bool __init have_multiple_modparms(void)
[ ... ]
> +static int host_bridges_populate(void)
> +{
> +	int rc = 0;
>  
> -	for (i = 0; i < ARRAY_SIZE(cxl_host_bridge); i++) {
> +	for (int i = 0; i < ARRAY_SIZE(cxl_host_bridge); i++) {
>  		struct acpi_device *adev = &host_bridge[i];
>  		struct platform_device *pdev;
>  
>  		pdev = platform_device_alloc("cxl_host_bridge", i);
> -		if (!pdev)
> +		if (!pdev) {
> +			rc = -ENOMEM;
>  			goto err_bridge;
> +		}

[Severity: High]
This is a pre-existing issue, but I see you fixed the missing rc = -ENOMEM
assignments during failure paths in this newly refactored function and others.

However, does the same missing rc = -ENOMEM assignment still exist in
other unrefactored topology initialization functions in
tools/testing/cxl/test/cxl.c?

For example, in cxl_single_topo_init():

	pdev = platform_device_alloc("cxl_host_bridge",
				     NR_CXL_HOST_BRIDGES + i);
	if (!pdev)
		goto err_bridge;

And similarly in cxl_rch_topo_init(), and for cxl_acpi in cxl_test_init()?

If platform_device_alloc() fails in these functions, could they return an
uninitialized rc or 0?

If they return 0, the test module is successfully loaded despite having freed
mock resources, leaving dangling pointers. When the module is subsequently
unloaded, cxl_test_exit() unregisters these platform devices again.

Could this cause a double-free and a kernel panic?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260629202720.3658117-1-dave.jiang@intel.com?part=3

Re: [PATCH v6 4/6] cxl/test: Add hierarchy enumeration support for type2 device

[Dave Jiang]

On 6/29/26 1:36 PM, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] The error path for cxl_test_init() incorrectly replaces platform_device_unregister() with platform_device_put() for cxl_acpi, leading to a resource leak and potential use-after-free.
> --

Uck. Merge error when doing the rebase. I'll get that fixed up.


> 
> commit 74917ddebbac04cd137d2f935b0132cdc7d979fe
> Author: Dave Jiang <dave.jiang@intel.com>
> cxl/test: Add hierarchy enumeration support for type2 device
> 
> This commit adds enumeration of type2 device hierarchy in cxl-test. The type2 
> device is configured to be directly attached to a root port instead of the 
> rp -> switch -> device setup used for type3 hierarchy.
> 
>> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
>> index 8abe066080bc8..1eac06ad46601 100644
>> --- a/tools/testing/cxl/test/cxl.c
>> +++ b/tools/testing/cxl/test/cxl.c
> [ ... ]
>> @@ -2156,17 +2314,9 @@ static __init int cxl_test_init(void)
>>  err_mem:
>>  	cxl_mem_exit();
>>  err_root:
>> -	platform_device_unregister(cxl_acpi);
>> -err_rch:
>> -	cxl_rch_topo_exit();
>> -err_single:
>> -	cxl_single_topo_exit();
>> -err_switches:
>> -	cxl_switches_remove();
>> -err_root_ports:
>> -	cxl_rootports_remove();
>> -err_host_bridges:
>> -	host_bridges_remove();
>> +	platform_device_put(cxl_acpi);
> 
> [Severity: High]
> Does this error path properly tear down the device if cxl_mem_init() or
> hmem_test_init() fails?
> 
> Since cxl_acpi was already successfully registered with the driver core via
> cxl_mock_platform_device_add() earlier in cxl_test_init(), it seems
> platform_device_unregister() should be used instead of platform_device_put().
> 
> Using platform_device_put() here only drops the initial allocation reference,
> leaving the device actively linked in the platform bus and sysfs hierarchies.
> 
> Because the module unload upon initialization failure will free its memory,
> could any subsequent access to the device's sysfs files dereference invalid
> memory and cause a use-after-free?
> 
>> +err_topo:
>> +	cxl_topo_exit();
>>  err_populate:
>>  	depopulate_all_mock_resources();
>>  err_gen_pool_add:
>