[PATCH v6 3/6] acpi/numa: Set the memory-side-cache size in memblocks

[Dan Williams]

From: Keith Busch <keith.busch@xxxxxxxxx>

Add memblock based enumeration of memory-side-cache of System RAM.
Detect the capability in early init through HMAT tables, and set the
size in the address range memblocks if a direct mapped side cache is
present.

Cc: <x86@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 arch/x86/Kconfig         |    1 +
 drivers/acpi/numa.c      |   32 ++++++++++++++++++++++++++++++++
 include/linux/memblock.h |   38 ++++++++++++++++++++++++++++++++++++++
 mm/Kconfig               |    3 +++
 mm/memblock.c            |   34 ++++++++++++++++++++++++++++++++++
 5 files changed, 108 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8689e794a43c..3f9c413d8eb5 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -171,6 +171,7 @@ config X86
 	select HAVE_KVM
 	select HAVE_LIVEPATCH			if X86_64
 	select HAVE_MEMBLOCK_NODE_MAP
+	select HAVE_MEMBLOCK_CACHE_INFO		if ACPI_NUMA
 	select HAVE_MIXED_BREAKPOINTS_REGS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index f5e09c39ff22..ec7e849f1c19 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -40,6 +40,12 @@ static int pxm_to_node_map[MAX_PXM_DOMAINS]
 static int node_to_pxm_map[MAX_NUMNODES]
 			= { [0 ... MAX_NUMNODES - 1] = PXM_INVAL };
 
+struct mem_cacheinfo {
+	phys_addr_t size;
+	bool direct_mapped;
+};
+static struct mem_cacheinfo side_cached_pxms[MAX_PXM_DOMAINS] __initdata;
+
 unsigned char acpi_srat_revision __initdata;
 int acpi_numa __initdata;
 
@@ -262,6 +268,8 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 	u64 start, end;
 	u32 hotpluggable;
 	int node, pxm;
+	u64 cache_size;
+	bool direct;
 
 	if (srat_disabled())
 		goto out_err;
@@ -308,6 +316,13 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 		pr_warn("SRAT: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
 			(unsigned long long)start, (unsigned long long)end - 1);
 
+	cache_size = side_cached_pxms[pxm].size;
+	direct = side_cached_pxms[pxm].direct_mapped;
+	if (cache_size &&
+	    memblock_set_sidecache(start, ma->length, cache_size, direct))
+		pr_warn("SRAT: Failed to mark side cached range [mem %#010Lx-%#010Lx] in memblock\n",
+			(unsigned long long)start, (unsigned long long)end - 1);
+
 	max_possible_pfn = max(max_possible_pfn, PFN_UP(end - 1));
 
 	return 0;
@@ -411,6 +426,18 @@ acpi_parse_memory_affinity(union acpi_subtable_headers * header,
 	return 0;
 }
 
+static int __init
+acpi_parse_cache(union acpi_subtable_headers *header, const unsigned long end)
+{
+	struct acpi_hmat_cache *c = (void *)header;
+	u32 attrs = (c->cache_attributes & ACPI_HMAT_CACHE_ASSOCIATIVITY) >> 8;
+
+	if (attrs == ACPI_HMAT_CA_DIRECT_MAPPED)
+		side_cached_pxms[c->memory_PD].direct_mapped = true;
+	side_cached_pxms[c->memory_PD].size += c->cache_size;
+	return 0;
+}
+
 static int __init acpi_parse_srat(struct acpi_table_header *table)
 {
 	struct acpi_table_srat *srat = (struct acpi_table_srat *)table;
@@ -460,6 +487,11 @@ int __init acpi_numa_init(void)
 					sizeof(struct acpi_table_srat),
 					srat_proc, ARRAY_SIZE(srat_proc), 0);
 
+		acpi_table_parse_entries(ACPI_SIG_HMAT,
+					 sizeof(struct acpi_table_hmat),
+					 ACPI_HMAT_TYPE_CACHE,
+					 acpi_parse_cache, 0);
+
 		cnt = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
 					    acpi_parse_memory_affinity, 0);
 	}
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index aee299a6aa76..29c3c88a5207 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -52,6 +52,8 @@ enum memblock_flags {
  * @size: size of the region
  * @flags: memory region attributes
  * @nid: NUMA node id
+ * @cache_size: size of memory side cache in bytes
+ * @direct_mapped: true if direct mapped cache associativity exists
  */
 struct memblock_region {
 	phys_addr_t base;
@@ -60,6 +62,10 @@ struct memblock_region {
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 	int nid;
 #endif
+#ifdef CONFIG_HAVE_MEMBLOCK_CACHE_INFO
+	phys_addr_t cache_size;
+	bool direct_mapped;
+#endif
 };
 
 /**
@@ -317,6 +323,38 @@ static inline int memblock_get_region_node(const struct memblock_region *r)
 }
 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
+#ifdef CONFIG_HAVE_MEMBLOCK_CACHE_INFO
+int memblock_set_sidecache(phys_addr_t base, phys_addr_t size,
+			   phys_addr_t cache_size, bool direct_mapped);
+
+static inline bool memblock_sidecache_direct_mapped(struct memblock_region *m)
+{
+	return m->direct_mapped;
+}
+
+static inline phys_addr_t memblock_sidecache_size(struct memblock_region *m)
+{
+	return m->cache_size;
+}
+#else
+static inline int memblock_set_sidecache(phys_addr_t base, phys_addr_t size,
+					 phys_addr_t cache_size,
+					 bool direct_mapped)
+{
+	return 0;
+}
+
+static inline phys_addr_t memblock_sidecache_size(struct memblock_region *m)
+{
+	return 0;
+}
+
+static inline bool memblock_sidecache_direct_mapped(struct memblock_region *m)
+{
+	return false;
+}
+#endif /* CONFIG_HAVE_MEMBLOCK_CACHE_INFO */
+
 /* Flags for memblock allocation APIs */
 #define MEMBLOCK_ALLOC_ANYWHERE	(~(phys_addr_t)0)
 #define MEMBLOCK_ALLOC_ACCESSIBLE	0
diff --git a/mm/Kconfig b/mm/Kconfig
index d85e39da47ae..c7944299a89e 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -142,6 +142,9 @@ config ARCH_DISCARD_MEMBLOCK
 config MEMORY_ISOLATION
 	bool
 
+config HAVE_MEMBLOCK_CACHE_INFO
+	bool
+
 #
 # Only be set on architectures that have completely implemented memory hotplug
 # feature. If you are not sure, don't touch it.
diff --git a/mm/memblock.c b/mm/memblock.c
index 9a2d5ae81ae1..8ebbc77f20c5 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -822,6 +822,40 @@ int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
 	return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0);
 }
 
+#ifdef CONFIG_HAVE_MEMBLOCK_CACHE_INFO
+/**
+ * memblock_set_sidecache - set the system memory cache info
+ * @base: base address of the region
+ * @size: size of the region
+ * @cache_size: system side cache size in bytes
+ * @direct: true if the cache has direct mapped associativity
+ *
+ * This function isolates region [@base, @base + @size), and saves the cache
+ * information.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_set_sidecache(phys_addr_t base, phys_addr_t size,
+			   phys_addr_t cache_size, bool direct_mapped)
+{
+	struct memblock_type *type = &memblock.memory;
+	int i, ret, start_rgn, end_rgn;
+
+	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
+	if (ret)
+		return ret;
+
+	for (i = start_rgn; i < end_rgn; i++) {
+		struct memblock_region *r = &type->regions[i];
+
+		r->cache_size = cache_size;
+		r->direct_mapped = direct_mapped;
+	}
+
+	return 0;
+}
+#endif
+
 /**
  * memblock_setclr_flag - set or clear flag for a memory region
  * @base: base address of the region