[PATCH v4 1/5] mm/memblock: Tag memblocks with crypto capabilities

Martin Fernandez
2021-12-16T19:23:09Z

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.

Signed-off-by: Martin Fernandez <martin.fernandez@eclypsium.com>
---
include/linux/memblock.h | 5 ++++
mm/memblock.c | 49 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 8adcf1fa8096..ec808ad93693 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -41,6 +41,7 @@ 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 */
@@ -48,6 +49,7 @@ enum memblock_flags {
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..61ec50647469 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
@@ -885,6 +906,34 @@ 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