[PATCH v6 1/6] mm/memblock: Tag memblocks with crypto capabilities

[Martin Fernandez <martin.fernandez@eclypsium.com>]

Add the capability to mark regions of the memory memory_type able of
hardware memory encryption.

Also add the capability to query if all regions of a memory node are
able to do hardware memory encryption to call it when initializing the
nodes. Warn the user if a node has both encryptable and
non-encryptable regions.

Signed-off-by: Martin Fernandez <martin.fernandez@eclypsium.com>
---
 include/linux/memblock.h | 15 ++++++----
 mm/memblock.c            | 64 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 9dc7cb239d21..73edcce165a5 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -41,13 +41,15 @@ extern unsigned long long max_possible_pfn;
  * via a driver, and never indicated in the firmware-provided memory map as
  * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the
  * kernel resource tree.
+ * @MEMBLOCK_CRYPTO_CAPABLE: capable of hardware encryption
  */
 enum memblock_flags {
-	MEMBLOCK_NONE		= 0x0,	/* No special request */
-	MEMBLOCK_HOTPLUG	= 0x1,	/* hotpluggable region */
-	MEMBLOCK_MIRROR		= 0x2,	/* mirrored region */
-	MEMBLOCK_NOMAP		= 0x4,	/* don't add to kernel direct mapping */
-	MEMBLOCK_DRIVER_MANAGED = 0x8,	/* always detected via a driver */
+	MEMBLOCK_NONE		= 0x0,		/* No special request */
+	MEMBLOCK_HOTPLUG	= 0x1,		/* hotpluggable region */
+	MEMBLOCK_MIRROR		= 0x2,		/* mirrored region */
+	MEMBLOCK_NOMAP		= 0x4,		/* don't add to kernel direct mapping */
+	MEMBLOCK_DRIVER_MANAGED = 0x8,		/* always detected via a driver */
+	MEMBLOCK_CRYPTO_CAPABLE = 0x10,		/* capable of hardware encryption */
 };
 
 /**
@@ -121,6 +123,9 @@ int memblock_physmem_add(phys_addr_t base, phys_addr_t size);
 void memblock_trim_memory(phys_addr_t align);
 bool memblock_overlaps_region(struct memblock_type *type,
 			      phys_addr_t base, phys_addr_t size);
+bool memblock_node_is_crypto_capable(int nid);
+int memblock_mark_crypto_capable(phys_addr_t base, phys_addr_t size);
+int memblock_clear_crypto_capable(phys_addr_t base, phys_addr_t size);
 int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
 int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
 int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
diff --git a/mm/memblock.c b/mm/memblock.c
index 1018e50566f3..fcf79befeab3 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -191,6 +191,42 @@ bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
 	return i < type->cnt;
 }
 
+/**
+ * memblock_node_is_crypto_capable - get if whole node is capable
+ * of encryption
+ * @nid: number of node
+ *
+ * Iterate over all memory memblock_type and find if all regions under
+ * node @nid are capable of hardware encryption.
+ *
+ * Return:
+ * true if every region in memory memblock_type is capable of
+ * encryption, false otherwise.
+ */
+bool __init_memblock memblock_node_is_crypto_capable(int nid)
+{
+	struct memblock_region *region;
+	bool crypto_capable = false;
+	bool not_crypto_capable = false;
+
+	for_each_mem_region(region) {
+		if (memblock_get_region_node(region) == nid) {
+			crypto_capable =
+				crypto_capable ||
+				(region->flags & MEMBLOCK_CRYPTO_CAPABLE);
+			not_crypto_capable =
+				not_crypto_capable ||
+				!(region->flags & MEMBLOCK_CRYPTO_CAPABLE);
+		}
+	}
+
+	if (crypto_capable && not_crypto_capable)
+		pr_warn_once("Node %d has regions that are encryptable and regions that aren't",
+			     nid);
+
+	return !not_crypto_capable;
+}
+
 /**
  * __memblock_find_range_bottom_up - find free area utility in bottom-up
  * @start: start of candidate range
@@ -885,6 +921,34 @@ static int __init_memblock memblock_setclr_flag(phys_addr_t base,
 	return 0;
 }
 
+/**
+ * memblock_mark_crypto_capable - Mark memory regions capable of hardware
+ * encryption with flag MEMBLOCK_CRYPTO_CAPABLE.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_mark_crypto_capable(phys_addr_t base,
+						 phys_addr_t size)
+{
+	return memblock_setclr_flag(base, size, 1, MEMBLOCK_CRYPTO_CAPABLE);
+}
+
+/**
+ * memblock_clear_crypto_capable - Clear flag MEMBLOCK_CRYPTO for a
+ * specified region.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_clear_crypto_capable(phys_addr_t base,
+						  phys_addr_t size)
+{
+	return memblock_setclr_flag(base, size, 0, MEMBLOCK_CRYPTO_CAPABLE);
+}
+
 /**
  * memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
  * @base: the base phys addr of the region
-- 
2.30.2