[PATCH v2] ACPI: NUMA: Add a node and memblk for each CFMWS not in SRAT

* [PATCH v2] ACPI: NUMA: Add a node and memblk for each CFMWS not in SRAT
@ 2021-10-18  3:07 alison.schofield
  2021-10-19  4:10 ` Ben Widawsky
  0 siblings, 1 reply; 3+ messages in thread
From: alison.schofield @ 2021-10-18  3:07 UTC (permalink / raw)
  To: Rafael J. Wysocki, Len Brown, Vishal Verma, Ira Weiny,
	Ben Widawsky, Dan Williams
  Cc: Alison Schofield, linux-cxl, linux-acpi

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 (CFMWS) of the ACPI CXL
Early Discovery Table (CEDT) to find all CXL memory ranges.
Create a NUMA node for each CFMWS 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>
---

Changes in v2:
- Use MAX_NUMNODES as max value when searching node_to_pxm_map() (0-day)
- Add braces around single statement for loop (coding style)
- Rename acpi_parse_cfmws() to acpi_cxl_cfmws_init to be more like other
  functions in this file doing similar work. 
- Comments: remove superflous and state importance of the init order,
  CFMWS after SRAT, (Ira, Dan)
- Add prototype for numa_add_memblk() (0-day)


 drivers/acpi/numa/srat.c | 70 ++++++++++++++++++++++++++++++++++++++++
 drivers/cxl/acpi.c       |  8 +++--
 include/linux/acpi.h     |  1 +
 3 files changed, 76 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
index b8795fc49097..4d26a4208af0 100644
--- a/drivers/acpi/numa/srat.c
+++ b/drivers/acpi/numa/srat.c
@@ -300,6 +300,67 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 }
 #endif /* defined(CONFIG_X86) || defined (CONFIG_ARM64) */
 
+static int __init acpi_cxl_cfmws_init(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;
+
+	/* Find the max PXM defined in the SRAT */
+	for (i = 0; i < MAX_NUMNODES - 1; i++) {
+		if (node_to_pxm_map[i] > pxm)
+			pxm = node_to_pxm_map[i];
+	}
+	/* Start assigning fake PXM values after the SRAT max PXM */
+	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 SRAT already described
+		 * the NUMA details for this HPA.
+		 */
+		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) {
+			/* CXL driver must handle the NUMA_NO_NODE case */
+			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 +539,15 @@ int __init acpi_numa_init(void)
 	/* SLIT: System Locality Information Table */
 	acpi_table_parse(ACPI_SIG_SLIT, acpi_parse_slit);
 
+	/*
+	 * CEDT: CXL Fixed Memory Window Structures (CFMWS)
+	 * must be parsed after the SRAT. It creates NUMA
+	 * Nodes for CXL memory ranges not already defined
+	 * in the SRAT and it assigns PXMs after the max PXM
+	 * defined in the SRAT.
+	 */
+	acpi_table_parse(ACPI_SIG_CEDT, acpi_cxl_cfmws_init);
+
 	if (cnt < 0)
 		return cnt;
 	else if (!parsed_numa_memblks)
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 54e9d4d2cf5f..02f765a494b1 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -122,9 +122,11 @@ static void cxl_add_cfmws_decoders(struct device *dev,
 				cfmws->base_hpa, cfmws->base_hpa +
 				cfmws->window_size - 1);
 		} else {
-			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\n",
+				dev_name(&cxld->dev),
+				phys_to_target_node(cxld->range.start),
+				cfmws->base_hpa,
+				cfmws->base_hpa + cfmws->window_size - 1);
 		}
 		cur += c->length;
 	}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 974d497a897d..f837fd715440 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -426,6 +426,7 @@ extern bool acpi_osi_is_win8(void);
 #ifdef CONFIG_ACPI_NUMA
 int acpi_map_pxm_to_node(int pxm);
 int acpi_get_node(acpi_handle handle);
+int __init numa_add_memblk(int nodeid, u64 start, u64 end);
 
 /**
  * pxm_to_online_node - Map proximity ID to online node

base-commit: 64570fbc14f8d7cb3fe3995f20e26bc25ce4b2cc
-- 
2.31.1


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