[PATCH v6 5/6] x86/efi: Tag e820_entries as crypto capable from EFI memmap

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

Add a function to iterate over the EFI Memory Map and mark the regions
tagged with EFI_MEMORY_CPU_CRYPTO in the e820_table; and call it from
efi_init if add_efi_memmap is disabled.

Also modify do_add_efi_memmap to mark the regions there.

If add_efi_memmap is false, also check that the e820_table has enough
size to (possibly) store also the EFI memmap.

Signed-off-by: Martin Fernandez <martin.fernandez@eclypsium.com>
---
 arch/x86/platform/efi/efi.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 147c30a81f15..3efa1c620c75 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -184,6 +184,8 @@ static void __init do_add_efi_memmap(void)
 		}
 
 		e820__range_add(start, size, e820_type);
+		if (md->attribute & EFI_MEMORY_CPU_CRYPTO)
+			e820__range_set_crypto_capable(start, size);
 	}
 	e820__update_table(e820_table);
 }
@@ -441,6 +443,34 @@ static int __init efi_config_init(const efi_config_table_type_t *arch_tables)
 	return ret;
 }
 
+static void __init efi_mark_e820_regions_as_crypto_capable(void)
+{
+	efi_memory_desc_t *md;
+
+	/*
+	 * Calling e820__range_set_crypto_capable several times
+	 * creates a bunch of entries in the E820 table. They probably
+	 * will get merged when calling update_table but we need the
+	 * space there anyway
+	 */
+	if (efi.memmap.nr_map + e820_table->nr_entries >= E820_MAX_ENTRIES) {
+		pr_err_once("E820 table is not large enough to fit EFI memmap; not marking entries as crypto capable\n");
+		return;
+	}
+
+	for_each_efi_memory_desc(md) {
+		if (md->attribute & EFI_MEMORY_CPU_CRYPTO)
+			e820__range_set_crypto_capable(md->phys_addr,
+						       md->num_pages << EFI_PAGE_SHIFT);
+	}
+
+	/*
+	 * We added and modified regions so it's good to update the
+	 * table to merge/sort
+	 */
+	e820__update_table(e820_table);
+}
+
 void __init efi_init(void)
 {
 	if (IS_ENABLED(CONFIG_X86_32) &&
@@ -494,6 +524,13 @@ void __init efi_init(void)
 	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 	efi_clean_memmap();
 
+	/*
+	 * If add_efi_memmap then there is no need to mark the regions
+	 * again
+	 */
+	if (!add_efi_memmap)
+		efi_mark_e820_regions_as_crypto_capable();
+
 	if (efi_enabled(EFI_DBG))
 		efi_print_memmap();
 }
-- 
2.30.2