[PATCH v6 4/6] x86/e820: Tag e820_entry with crypto capabilities

Martin Fernandez
2022-02-03T16:44:17Z

Add a new enum for crypto capabilities.

Add a new member in e820_entry to hold whether an entry is able to do
hardware memory encryption or not.

Add a new function e820__range_set_crypto_capable to mark all the
entries in a range of addresses as encryptable. This will be called
when initializing EFI.

Change e820__update_table to handle merging and overlap problems
taking into account crypto_capable.

Signed-off-by: Martin Fernandez <martin.fernandez@eclypsium.com>
---
arch/x86/include/asm/e820/api.h | 1 +
arch/x86/include/asm/e820/types.h | 12 +++-
arch/x86/kernel/e820.c | 114 ++++++++++++++++++++++++++++--
3 files changed, 119 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index e8f58ddd06d9..4b3b01fafdd1 100644
--- a/arch/x86/include/asm/e820/api.h
+++ b/arch/x86/include/asm/e820/api.h
@@ -17,6 +17,7 @@ extern bool e820__mapped_all(u64 start, u64 end, enum e820_type type);
extern void e820__range_add (u64 start, u64 size, enum e820_type type);
extern u64 e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type);
extern u64 e820__range_remove(u64 start, u64 size, enum e820_type old_type, bool check_type);
+extern u64 e820__range_set_crypto_capable(u64 start, u64 size);

extern void e820__print_table(char *who);
extern int e820__update_table(struct e820_table *table);
diff --git a/arch/x86/include/asm/e820/types.h b/arch/x86/include/asm/e820/types.h
index 314f75d886d0..aef03c665f5e 100644
--- a/arch/x86/include/asm/e820/types.h
+++ b/arch/x86/include/asm/e820/types.h
@@ -46,6 +46,11 @@ enum e820_type {
E820_TYPE_RESERVED_KERN = 128,
};

+enum e820_crypto_capabilities {
+ E820_NOT_CRYPTO_CAPABLE = 0,
+ E820_CRYPTO_CAPABLE = 1,
+};
+
/*
* A single E820 map entry, describing a memory range of [addr...addr+size-1],
* of 'type' memory type:
@@ -53,9 +58,10 @@ enum e820_type {
* (We pack it because there can be thousands of them on large systems.)
*/
struct e820_entry {
- u64 addr;
- u64 size;
- enum e820_type type;
+ u64 addr;
+ u64 size;
+ enum e820_type type;
+ enum e820_crypto_capabilities crypto_capable;
} __attribute__((packed));

/*
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 89b78c6b345b..098882d02120 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -163,7 +163,9 @@ int e820__get_entry_type(u64 start, u64 end)
/*
* Add a memory region to the kernel E820 map.
*/
-static void __init __e820__range_add(struct e820_table *table, u64 start, u64 size, enum e820_type type)
+static void __init __e820__range_add(struct e820_table *table, u64 start,
+ u64 size, enum e820_type type,
+ enum e820_crypto_capabilities crypto_capable)
{
int x = table->nr_entries;

@@ -176,12 +178,13 @@ static void __init __e820__range_add(struct e820_table *table, u64 start, u64 si
table->entries[x].addr = start;
table->entries[x].size = size;
table->entries[x].type = type;
+ table->entries[x].crypto_capable = crypto_capable;
table->nr_entries++;
}

void __init e820__range_add(u64 start, u64 size, enum e820_type type)
{
- __e820__range_add(e820_table, start, size, type);
+ __e820__range_add(e820_table, start, size, type, E820_NOT_CRYPTO_CAPABLE);
}

static void __init e820_print_type(enum e820_type type)
@@ -211,6 +214,8 @@ void __init e820__print_table(char *who)
e820_table->entries[i].addr + e820_table->entries[i].size - 1);

e820_print_type(e820_table->entries[i].type);
+ if (e820_table->entries[i].crypto_capable == E820_CRYPTO_CAPABLE)
+ pr_cont("; crypto-capable");
pr_cont("\n");
}
}
@@ -327,6 +332,7 @@ int __init e820__update_table(struct e820_table *table)
unsigned long long last_addr;
u32 new_nr_entries, overlap_entries;
u32 i, chg_idx, chg_nr;
+ enum e820_crypto_capabilities current_crypto, last_crypto;

/* If there's only one memory region, don't bother: */
if (table->nr_entries < 2)
@@ -367,6 +373,7 @@ int __init e820__update_table(struct e820_table *table)
new_nr_entries = 0; /* Index for creating new map entries */
last_type = 0; /* Start with undefined memory type */
last_addr = 0; /* Start with 0 as last starting address */
+ last_crypto = E820_NOT_CRYPTO_CAPABLE;

/* Loop through change-points, determining effect on the new map: */
for (chg_idx = 0; chg_idx < chg_nr; chg_idx++) {
@@ -388,13 +395,19 @@ int __init e820__update_table(struct e820_table *table)
* 1=usable, 2,3,4,4+=unusable)
*/
current_type = 0;
+ current_crypto = E820_CRYPTO_CAPABLE;
for (i = 0; i < overlap_entries; i++) {
+ if (overlap_list[i]->crypto_capable < current_crypto)
+ current_crypto = overlap_list[i]->crypto_capable;
+
if (overlap_list[i]->type > current_type)
current_type = overlap_list[i]->type;
}

/* Continue building up new map based on this information: */
- if (current_type != last_type || e820_nomerge(current_type)) {
+ if (current_type != last_type ||
+ current_crypto != last_crypto ||
+ e820_nomerge(current_type)) {
if (last_type != 0) {
new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
/* Move forward only if the new size was non-zero: */
@@ -406,9 +419,12 @@ int __init e820__update_table(struct e820_table *table)
if (current_type != 0) {
new_entries[new_nr_entries].addr = change_point[chg_idx]->addr;
new_entries[new_nr_entries].type = current_type;
+ new_entries[new_nr_entries].crypto_capable = current_crypto;
+
last_addr = change_point[chg_idx]->addr;
}
last_type = current_type;
+ last_crypto = current_crypto;
}
}

@@ -505,6 +521,19 @@ struct e820_type_updater_data {
enum e820_type new_type;
};

+/**
+ * e820_crypto_updater_data - Helper type for
+ * __e820__range_update_crypto().
+ * @crypto_capable: crypto_capable parameter of
+ * __e820__range_update_crypto().
+ *
+ * This is intended to be used as the @data argument for the
+ * e820_entry_updater callbacks.
+ */
+struct e820_crypto_updater_data {
+ enum e820_crypto_capabilities crypto_capable;
+};
+
/**
* __e820__handle_intersected_range_update() - Helper function for
* __e820__handle_range_update().
@@ -615,7 +644,8 @@ __e820__handle_range_update(struct e820_table *table,
* of the current entry
*/
__e820__range_add(table, end, entry_end - end,
- entry->type);
+ entry->type,
+ entry->crypto_capable);

updated_size += size;
} else {
@@ -656,7 +686,7 @@ static void __init type_updater__new(struct e820_table *table, u64 new_start,
(struct e820_type_updater_data *)data;

__e820__range_add(table, new_start, new_size,
- type_updater_data->new_type);
+ type_updater_data->new_type, original->crypto_capable);
}

static u64 __init __e820__range_update(struct e820_table *table, u64 start,
@@ -686,6 +716,62 @@ static u64 __init __e820__range_update(struct e820_table *table, u64 start,
return __e820__handle_range_update(table, start, size, &updater, &data);
}

+static bool __init crypto_updater__should_update(const struct e820_entry *entry,
+ const void *data)
+{
+ struct e820_crypto_updater_data *crypto_updater_data =
+ (struct e820_crypto_updater_data *)data;
+
+ return crypto_updater_data->crypto_capable != entry->crypto_capable;
+}
+
+static void __init crypto_updater__update(struct e820_entry *entry,
+ const void *data)
+{
+ struct e820_crypto_updater_data *crypto_updater_data =
+ (struct e820_crypto_updater_data *)data;
+
+ entry->crypto_capable = crypto_updater_data->crypto_capable;
+}
+
+static void __init crypto_updater__new(struct e820_table *table, u64 new_start,
+ u64 new_size,
+ const struct e820_entry *original,
+ const void *data)
+{
+ struct e820_crypto_updater_data *crypto_updater_data =
+ (struct e820_crypto_updater_data *)data;
+
+ __e820__range_add(table, new_start, new_size, original->type,
+ crypto_updater_data->crypto_capable);
+}
+
+static u64 __init
+__e820__range_update_crypto(struct e820_table *table, u64 start, u64 size,
+ enum e820_crypto_capabilities crypto_capable)
+{
+ struct e820_entry_updater updater = {
+ .should_update = crypto_updater__should_update,
+ .update = crypto_updater__update,
+ .new = crypto_updater__new
+ };
+
+ struct e820_crypto_updater_data data = {
+ .crypto_capable = crypto_capable,
+ };
+
+ printk(KERN_DEBUG "e820: crypto update [mem %#018Lx-%#018Lx]", start,
+ start + size - 1);
+ pr_cont(" ==> ");
+ if (crypto_capable == E820_CRYPTO_CAPABLE)
+ pr_cont("crypto capable");
+ else
+ pr_cont("not crypto capable");
+ pr_cont("\n");
+
+ return __e820__handle_range_update(table, start, size, &updater, &data);
+}
+
static bool __init remover__should_update(const struct e820_entry *entry,
const void *data)
{
@@ -782,6 +868,22 @@ static u64 __init e820__range_update_kexec(u64 start, u64 size,
return __e820__range_update(e820_table_kexec, start, size, old_type, new_type);
}

+/**
+ * e820__range_set_crypto_capable() - Set %E820_CRYPTO_CAPABLE to a
+ * given range of addresses in e820_table.
+ * @start: Start of the range.
+ * @size: Size of the range.
+ *
+ * Set %E820_CRYPTO_CAPABLE to [@start, @start + @size) in e820_table.
+ *
+ * Return: The size updated.
+ */
+u64 __init e820__range_set_crypto_capable(u64 start, u64 size)
+{
+ return __e820__range_update_crypto(e820_table, start, size,
+ E820_CRYPTO_CAPABLE);
+}
+
void __init e820__update_table_print(void)
{
if (e820__update_table(e820_table))
@@ -1505,6 +1607,8 @@ void __init e820__memblock_setup(void)
continue;

memblock_add(entry->addr, entry->size);
+ if (entry->crypto_capable == E820_CRYPTO_CAPABLE)
+ memblock_mark_crypto_capable(entry->addr, entry->size);
}

/* Throw away partial pages: */
--
2.30.2