[PATCH v2 1/5] Extend memblock to support memory encryption

[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.

Signed-off-by: Martin Fernandez <martin.fernandez@eclypsium.com>
---
 include/linux/memblock.h |  6 ++++
 mm/memblock.c            | 74 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 34de69b3b8ba..945af2cc7966 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -31,6 +31,7 @@ extern unsigned long long max_possible_pfn;
  * @MEMBLOCK_HOTPLUG: hotpluggable region
  * @MEMBLOCK_MIRROR: mirrored region
  * @MEMBLOCK_NOMAP: don't add to kernel direct mapping and treat as
+ * @MEMBLOCK_CRYPTO_CAPABLE: capable of hardware encryption
  * reserved in the memory map; refer to memblock_mark_nomap() description
  * for further details
  */
@@ -39,6 +40,7 @@ enum memblock_flags {
 	MEMBLOCK_HOTPLUG	= 0x1,	/* hotpluggable region */
 	MEMBLOCK_MIRROR		= 0x2,	/* mirrored region */
 	MEMBLOCK_NOMAP		= 0x4,	/* don't add to kernel direct mapping */
+	MEMBLOCK_CRYPTO_CAPABLE = 0x8,  /* capable of hardware encryption */
 };
 
 /**
@@ -102,6 +104,7 @@ static inline void memblock_discard(void) {}
 void memblock_allow_resize(void);
 int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid);
 int memblock_add(phys_addr_t base, phys_addr_t size);
+int memblock_add_crypto_capable(phys_addr_t base, phys_addr_t size);
 int memblock_remove(phys_addr_t base, phys_addr_t size);
 int memblock_free(phys_addr_t base, phys_addr_t size);
 int memblock_reserve(phys_addr_t base, phys_addr_t size);
@@ -111,6 +114,9 @@ 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 5096500b2647..805e0e43ec66 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -191,6 +191,27 @@ 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.
+ */
+bool __init_memblock memblock_node_is_crypto_capable(int nid)
+{
+	struct memblock_region *region;
+
+	for_each_mem_region(region) {
+		if ((memblock_get_region_node(region) == nid) &&
+		    !(region->flags & MEMBLOCK_CRYPTO_CAPABLE))
+			return false;
+	}
+
+	return true;
+}
+
 /**
  * __memblock_find_range_bottom_up - find free area utility in bottom-up
  * @start: start of candidate range
@@ -694,6 +715,31 @@ int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
 	return memblock_add_range(&memblock.memory, base, size, MAX_NUMNODES, 0);
 }
 
+/**
+ * memblock_add_crypto_capable - add new memblock region capable of
+ * hardware encryption
+ * @base: base address of the new region
+ * @size: size of the new region
+ *
+ * Add new memblock region [@base, @base + @size) to the "memory" type
+ * and set the MEMBLOCK_CRYPTO_CAPABLE flag. See memblock_add_range()
+ * description for mode details
+ *
+ * Return:
+ * 0 on success, -errno on failure.
+ */
+int __init_memblock memblock_add_crypto_capable(phys_addr_t base,
+						phys_addr_t size)
+{
+	const phys_addr_t end = base + size - 1;
+
+	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
+		     &base, &end, (void *)_RET_IP_);
+
+	return memblock_add_range(&memblock.memory, base, size, MAX_NUMNODES,
+				  MEMBLOCK_CRYPTO_CAPABLE);
+}
+
 /**
  * memblock_isolate_range - isolate given range into disjoint memblocks
  * @type: memblock type to isolate range for
@@ -884,6 +930,34 @@ 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