[PATCH] ACPI: NUMA: Add a node and memblk for each CFMWS not in SRAT

alison.schofield
2021-10-09T01:45:31Z

From: Alison Schofield <alison.schofield@intel.com>

During NUMA init, CXL memory defined in the SRAT Memory Affinity
subtable may be assigned to a NUMA node. Since there is no
requirement that the SRAT be comprehensive for CXL memory another
mechanism is needed to assign NUMA nodes to CXL memory not identified
in the SRAT.

Use the CXL Fixed Memory Window Structure's (CFMWS) of the ACPI CXL
Early Discovery Table (CEDT) to find all CXL memory ranges. Create a
NUMA node for each range that is not already assigned to a NUMA node.
Add a memblk attaching its host physical address range to the node.

Note that these ranges may not actually map any memory at boot time.
They may describe persistent capacity or may be present to enable
hot-plug.

Consumers can use phys_to_target_node() to discover the NUMA node.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
drivers/acpi/numa/srat.c | 58 ++++++++++++++++++++++++++++++++++++++++
drivers/cxl/acpi.c | 8 +++---
2 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
index b8795fc49097..568e033e6c3f 100644
--- a/drivers/acpi/numa/srat.c
+++ b/drivers/acpi/numa/srat.c
@@ -300,6 +300,61 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
}
#endif /* defined(CONFIG_X86) || defined (CONFIG_ARM64) */

+/* Add a NUMA node and memblk for each node-less CFMWS */
+static int __init acpi_parse_cfmws(struct acpi_table_header *acpi_cedt)
+{
+ struct acpi_cedt_cfmws *cfmws;
+ acpi_size len, cur = 0;
+ void *cedt_subtable;
+ int i, pxm, node;
+ u64 start, end;
+
+ /* Use fake PXM values starting after the max PXM found in the SRAT */
+ for (i = 0; i < MAX_PXM_DOMAINS - 1; i++)
+ if (node_to_pxm_map[i] > pxm)
+ pxm = node_to_pxm_map[i];
+ pxm++;
+
+ len = acpi_cedt->length - sizeof(*acpi_cedt);
+ cedt_subtable = acpi_cedt + 1;
+
+ while (cur < len) {
+ struct acpi_cedt_header *c = cedt_subtable + cur;
+
+ if (c->type != ACPI_CEDT_TYPE_CFMWS)
+ goto next;
+
+ cfmws = cedt_subtable + cur;
+ if (cfmws->header.length < sizeof(*cfmws)) {
+ pr_warn_once("CFMWS entry skipped:invalid length:%u\n",
+ cfmws->header.length);
+ goto next;
+ }
+
+ start = cfmws->base_hpa;
+ end = cfmws->base_hpa + cfmws->window_size;
+
+ /* Skip if the HPA is already assigned to a NUMA node */
+ node = phys_to_target_node(start);
+ if (node != NUMA_NO_NODE)
+ goto next;
+
+ node = acpi_map_pxm_to_node(pxm);
+ if (node == NUMA_NO_NODE) {
+ pr_err("ACPI NUMA: Too many proximity domains.\n");
+ return -EINVAL;
+ }
+ if (numa_add_memblk(node, start, end) < 0) {
+ pr_warn("ACPI NUMA: Failed to add memblk for CFMWS node %d [mem %#llx-%#llx]\n",
+ node, start, end);
+ }
+ pxm++;
+next:
+ cur += c->length;
+ }
+ return 0;
+}
+
static int __init acpi_parse_slit(struct acpi_table_header *table)
{
struct acpi_table_slit *slit = (struct acpi_table_slit *)table;
@@ -478,6 +533,9 @@ int __init acpi_numa_init(void)
/* SLIT: System Locality Information Table */
acpi_table_parse(ACPI_SIG_SLIT, acpi_parse_slit);

+ /* CEDT: CXL Early Discovery Table */
+ acpi_table_parse(ACPI_SIG_CEDT, acpi_parse_cfmws);
+
if (cnt < 0)
return cnt;
else if (!parsed_numa_memblks)
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index dadc7f64b9ff..3798841c3418 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -144,9 +144,11 @@ static void cxl_add_cfmws_decoders(struct device *dev,
cfmws->window_size - 1);
goto next;
}
- dev_dbg(dev, "add: %s range %#llx-%#llx\n",
- dev_name(&cxld->dev), cfmws->base_hpa,
- cfmws->base_hpa + cfmws->window_size - 1);
+ dev_dbg(dev, "add:%s node:%d range:%#llx-%#llx restrict:%#x\n",
+ dev_name(&cxld->dev),
+ phys_to_target_node(cxld->range.start),
+ cxld->range.start, cxld->range.end,
+ cfmws->restrictions);
next:
cur += c->length;
}
--
2.31.1