[PATCH v6 2/7] libcxl: Add Dynamic RAM A partition mode support
From: Anisa Su
Date: Sat May 23 2026 - 05:56:39 EST
From: Ira Weiny <ira.weiny@xxxxxxxxx>
Dynamic capacity partitions are exposed as a singular dynamic ram
partition.
Add CXL library support to read this partition information.
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
Documentation/cxl/lib/libcxl.txt | 6 +++--
cxl/lib/libcxl.c | 43 ++++++++++++++++++++++++++++++++
cxl/lib/libcxl.sym | 4 +++
cxl/lib/private.h | 3 +++
cxl/libcxl.h | 10 +++++++-
5 files changed, 63 insertions(+), 3 deletions(-)
diff --git a/Documentation/cxl/lib/libcxl.txt b/Documentation/cxl/lib/libcxl.txt
index 5c3ebd4..9921ac1 100644
--- a/Documentation/cxl/lib/libcxl.txt
+++ b/Documentation/cxl/lib/libcxl.txt
@@ -74,6 +74,7 @@ int cxl_memdev_get_major(struct cxl_memdev *memdev);
int cxl_memdev_get_minor(struct cxl_memdev *memdev);
unsigned long long cxl_memdev_get_pmem_size(struct cxl_memdev *memdev);
unsigned long long cxl_memdev_get_ram_size(struct cxl_memdev *memdev);
+unsigned long long cxl_memdev_get_dynamic_ram_a_size(struct cxl_memdev *memdev);
const char *cxl_memdev_get_firmware_version(struct cxl_memdev *memdev);
size_t cxl_memdev_get_label_size(struct cxl_memdev *memdev);
int cxl_memdev_nvdimm_bridge_active(struct cxl_memdev *memdev);
@@ -93,8 +94,8 @@ The character device node for command submission can be found by default
at /dev/cxl/mem%d, or created with a major / minor returned from
cxl_memdev_get_{major,minor}().
-The 'pmem_size' and 'ram_size' attributes return the current
-provisioning of DPA (Device Physical Address / local capacity) in the
+The 'pmem_size', 'ram_size', and 'dynamic_ram_a_size' attributes return the
+current provisioning of DPA (Device Physical Address / local capacity) in the
device.
cxl_memdev_get_numa_node() returns the affinitized CPU node number if
@@ -453,6 +454,7 @@ enum cxl_decoder_mode {
CXL_DECODER_MODE_MIXED,
CXL_DECODER_MODE_PMEM,
CXL_DECODER_MODE_RAM,
+ CXL_DECODER_MODE_DYNAMIC_RAM_A,
};
enum cxl_decoder_mode cxl_decoder_get_mode(struct cxl_decoder *decoder);
int cxl_decoder_set_mode(struct cxl_decoder *decoder, enum cxl_decoder_mode mode);
diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
index e55a7b4..be0bc03 100644
--- a/cxl/lib/libcxl.c
+++ b/cxl/lib/libcxl.c
@@ -501,6 +501,9 @@ CXL_EXPORT bool cxl_region_qos_class_mismatch(struct cxl_region *region)
} else if (region->mode == CXL_DECODER_MODE_PMEM) {
if (root_decoder->qos_class != memdev->pmem_qos_class)
return true;
+ } else if (region->mode == CXL_DECODER_MODE_DYNAMIC_RAM_A) {
+ if (root_decoder->qos_class != memdev->dynamic_ram_a_qos_class)
+ return true;
}
}
@@ -1426,6 +1429,10 @@ static void *add_cxl_memdev(void *parent, int id, const char *cxlmem_base)
if (sysfs_read_attr(ctx, path, buf) == 0)
memdev->ram_size = strtoull(buf, NULL, 0);
+ sprintf(path, "%s/dynamic_ram_a/size", cxlmem_base);
+ if (sysfs_read_attr(ctx, path, buf) == 0)
+ memdev->dynamic_ram_a_size = strtoull(buf, NULL, 0);
+
sprintf(path, "%s/pmem/qos_class", cxlmem_base);
if (sysfs_read_attr(ctx, path, buf) < 0)
memdev->pmem_qos_class = CXL_QOS_CLASS_NONE;
@@ -1438,6 +1445,12 @@ static void *add_cxl_memdev(void *parent, int id, const char *cxlmem_base)
else
memdev->ram_qos_class = atoi(buf);
+ sprintf(path, "%s/dynamic_ram_a/qos_class", cxlmem_base);
+ if (sysfs_read_attr(ctx, path, buf) < 0)
+ memdev->dynamic_ram_a_qos_class = CXL_QOS_CLASS_NONE;
+ else
+ memdev->dynamic_ram_a_qos_class = atoi(buf);
+
sprintf(path, "%s/payload_max", cxlmem_base);
if (sysfs_read_attr(ctx, path, buf) == 0) {
memdev->payload_max = strtoull(buf, NULL, 0);
@@ -1685,6 +1698,11 @@ CXL_EXPORT unsigned long long cxl_memdev_get_ram_size(struct cxl_memdev *memdev)
return memdev->ram_size;
}
+CXL_EXPORT unsigned long long cxl_memdev_get_dynamic_ram_a_size(struct cxl_memdev *memdev)
+{
+ return memdev->dynamic_ram_a_size;
+}
+
CXL_EXPORT int cxl_memdev_get_pmem_qos_class(struct cxl_memdev *memdev)
{
return memdev->pmem_qos_class;
@@ -1695,6 +1713,11 @@ CXL_EXPORT int cxl_memdev_get_ram_qos_class(struct cxl_memdev *memdev)
return memdev->ram_qos_class;
}
+CXL_EXPORT int cxl_memdev_get_dynamic_ram_a_qos_class(struct cxl_memdev *memdev)
+{
+ return memdev->dynamic_ram_a_qos_class;
+}
+
CXL_EXPORT const char *cxl_memdev_get_firmware_verison(struct cxl_memdev *memdev)
{
return memdev->firmware_version;
@@ -2465,6 +2488,8 @@ static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)
decoder->mode = CXL_DECODER_MODE_MIXED;
else if (strcmp(buf, "none") == 0)
decoder->mode = CXL_DECODER_MODE_NONE;
+ else if (strcmp(buf, "dynamic_ram_a") == 0)
+ decoder->mode = CXL_DECODER_MODE_DYNAMIC_RAM_A;
else
decoder->mode = CXL_DECODER_MODE_MIXED;
} else
@@ -2504,6 +2529,7 @@ static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)
case CXL_PORT_SWITCH:
decoder->pmem_capable = true;
decoder->volatile_capable = true;
+ decoder->dynamic_ram_a_capable = true;
decoder->mem_capable = true;
decoder->accelmem_capable = true;
sprintf(path, "%s/locked", cxldecoder_base);
@@ -2528,6 +2554,7 @@ static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)
{ "cap_type3", &decoder->mem_capable },
{ "cap_ram", &decoder->volatile_capable },
{ "cap_pmem", &decoder->pmem_capable },
+ { "cap_dynamic_ram_a", &decoder->dynamic_ram_a_capable },
{ "locked", &decoder->locked },
};
@@ -2778,6 +2805,9 @@ CXL_EXPORT int cxl_decoder_set_mode(struct cxl_decoder *decoder,
case CXL_DECODER_MODE_RAM:
sprintf(buf, "ram");
break;
+ case CXL_DECODER_MODE_DYNAMIC_RAM_A:
+ sprintf(buf, "dynamic_ram_a");
+ break;
default:
err(ctx, "%s: unsupported mode: %d\n",
cxl_decoder_get_devname(decoder), mode);
@@ -2829,6 +2859,11 @@ CXL_EXPORT bool cxl_decoder_is_volatile_capable(struct cxl_decoder *decoder)
return decoder->volatile_capable;
}
+CXL_EXPORT bool cxl_decoder_is_dynamic_ram_a_capable(struct cxl_decoder *decoder)
+{
+ return decoder->dynamic_ram_a_capable;
+}
+
CXL_EXPORT bool cxl_decoder_is_mem_capable(struct cxl_decoder *decoder)
{
return decoder->mem_capable;
@@ -2903,6 +2938,8 @@ static struct cxl_region *cxl_decoder_create_region(struct cxl_decoder *decoder,
sprintf(path, "%s/create_pmem_region", decoder->dev_path);
else if (mode == CXL_DECODER_MODE_RAM)
sprintf(path, "%s/create_ram_region", decoder->dev_path);
+ else if (mode == CXL_DECODER_MODE_DYNAMIC_RAM_A)
+ sprintf(path, "%s/create_dynamic_ram_a_region", decoder->dev_path);
rc = sysfs_read_attr(ctx, path, buf);
if (rc < 0) {
@@ -2954,6 +2991,12 @@ cxl_decoder_create_ram_region(struct cxl_decoder *decoder)
return cxl_decoder_create_region(decoder, CXL_DECODER_MODE_RAM);
}
+CXL_EXPORT struct cxl_region *
+cxl_decoder_create_dynamic_ram_a_region(struct cxl_decoder *decoder)
+{
+ return cxl_decoder_create_region(decoder, CXL_DECODER_MODE_DYNAMIC_RAM_A);
+}
+
CXL_EXPORT int cxl_decoder_get_nr_targets(struct cxl_decoder *decoder)
{
return decoder->nr_targets;
diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym
index ed4429f..258bdd3 100644
--- a/cxl/lib/libcxl.sym
+++ b/cxl/lib/libcxl.sym
@@ -294,6 +294,10 @@ global:
cxl_memdev_get_fwctl;
cxl_fwctl_get_major;
cxl_fwctl_get_minor;
+ cxl_memdev_get_dynamic_ram_a_size;
+ cxl_memdev_get_dynamic_ram_a_qos_class;
+ cxl_decoder_is_dynamic_ram_a_capable;
+ cxl_decoder_create_dynamic_ram_a_region;
} LIBECXL_8;
LIBCXL_10 {
diff --git a/cxl/lib/private.h b/cxl/lib/private.h
index d2d71fc..37b7b06 100644
--- a/cxl/lib/private.h
+++ b/cxl/lib/private.h
@@ -52,8 +52,10 @@ struct cxl_memdev {
struct list_node list;
unsigned long long pmem_size;
unsigned long long ram_size;
+ unsigned long long dynamic_ram_a_size;
int ram_qos_class;
int pmem_qos_class;
+ int dynamic_ram_a_qos_class;
int payload_max;
size_t lsa_size;
struct kmod_module *module;
@@ -159,6 +161,7 @@ struct cxl_decoder {
unsigned int interleave_granularity;
bool pmem_capable;
bool volatile_capable;
+ bool dynamic_ram_a_capable;
bool mem_capable;
bool accelmem_capable;
bool locked;
diff --git a/cxl/libcxl.h b/cxl/libcxl.h
index e91af90..fd41122 100644
--- a/cxl/libcxl.h
+++ b/cxl/libcxl.h
@@ -75,8 +75,10 @@ struct cxl_fwctl *cxl_memdev_get_fwctl(struct cxl_memdev *memdev);
struct cxl_ctx *cxl_memdev_get_ctx(struct cxl_memdev *memdev);
unsigned long long cxl_memdev_get_pmem_size(struct cxl_memdev *memdev);
unsigned long long cxl_memdev_get_ram_size(struct cxl_memdev *memdev);
+unsigned long long cxl_memdev_get_dynamic_ram_a_size(struct cxl_memdev *memdev);
int cxl_memdev_get_pmem_qos_class(struct cxl_memdev *memdev);
int cxl_memdev_get_ram_qos_class(struct cxl_memdev *memdev);
+int cxl_memdev_get_dynamic_ram_a_qos_class(struct cxl_memdev *memdev);
const char *cxl_memdev_get_firmware_verison(struct cxl_memdev *memdev);
bool cxl_memdev_fw_update_in_progress(struct cxl_memdev *memdev);
size_t cxl_memdev_fw_update_get_remaining(struct cxl_memdev *memdev);
@@ -210,6 +212,7 @@ enum cxl_decoder_mode {
CXL_DECODER_MODE_MIXED,
CXL_DECODER_MODE_PMEM,
CXL_DECODER_MODE_RAM,
+ CXL_DECODER_MODE_DYNAMIC_RAM_A,
};
static inline const char *cxl_decoder_mode_name(enum cxl_decoder_mode mode)
@@ -219,9 +222,10 @@ static inline const char *cxl_decoder_mode_name(enum cxl_decoder_mode mode)
[CXL_DECODER_MODE_MIXED] = "mixed",
[CXL_DECODER_MODE_PMEM] = "pmem",
[CXL_DECODER_MODE_RAM] = "ram",
+ [CXL_DECODER_MODE_DYNAMIC_RAM_A] = "dynamic_ram_a",
};
- if (mode < CXL_DECODER_MODE_NONE || mode > CXL_DECODER_MODE_RAM)
+ if (mode < CXL_DECODER_MODE_NONE || mode > CXL_DECODER_MODE_DYNAMIC_RAM_A)
mode = CXL_DECODER_MODE_NONE;
return names[mode];
}
@@ -235,6 +239,8 @@ cxl_decoder_mode_from_ident(const char *ident)
return CXL_DECODER_MODE_RAM;
else if (strcmp(ident, "pmem") == 0)
return CXL_DECODER_MODE_PMEM;
+ else if (strcmp(ident, "dynamic_ram_a") == 0)
+ return CXL_DECODER_MODE_DYNAMIC_RAM_A;
return CXL_DECODER_MODE_NONE;
}
@@ -264,6 +270,7 @@ cxl_decoder_get_target_type(struct cxl_decoder *decoder);
bool cxl_decoder_is_pmem_capable(struct cxl_decoder *decoder);
bool cxl_decoder_is_volatile_capable(struct cxl_decoder *decoder);
bool cxl_decoder_is_mem_capable(struct cxl_decoder *decoder);
+bool cxl_decoder_is_dynamic_ram_a_capable(struct cxl_decoder *decoder);
bool cxl_decoder_is_accelmem_capable(struct cxl_decoder *decoder);
bool cxl_decoder_is_locked(struct cxl_decoder *decoder);
unsigned int
@@ -272,6 +279,7 @@ unsigned int cxl_decoder_get_interleave_ways(struct cxl_decoder *decoder);
struct cxl_region *cxl_decoder_get_region(struct cxl_decoder *decoder);
struct cxl_region *cxl_decoder_create_pmem_region(struct cxl_decoder *decoder);
struct cxl_region *cxl_decoder_create_ram_region(struct cxl_decoder *decoder);
+struct cxl_region *cxl_decoder_create_dynamic_ram_a_region(struct cxl_decoder *decoder);
struct cxl_decoder *cxl_decoder_get_by_name(struct cxl_ctx *ctx,
const char *ident);
struct cxl_memdev *cxl_decoder_get_memdev(struct cxl_decoder *decoder);
--
2.43.0