[PATCH v5 3/5] x86/e820: Tag e820_entry with crypto capabilities

From: Martin Fernandez
Date: Thu Jan 13 2022 - 16:31:08 EST

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_update_crypto similar to
__e820__range_update but to update crypto capabilities.

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

Add a function to mark a range as crypto, using
__e820__range_update_crypto in the background. This will be called
when initializing EFI.

Signed-off-by: Martin Fernandez <martin.fernandez@xxxxxxxxxxxxx>
---
arch/x86/include/asm/e820/api.h | 1 +
arch/x86/include/asm/e820/types.h | 12 +++-
arch/x86/kernel/e820.c | 112 ++++++++++++++++++++++++++++--
3 files changed, 115 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index e8f58ddd06d9..677dcbabcc8b 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_mark_as_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 bc0657f0deed..bbf67b77bd18 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;
}
}

@@ -497,8 +513,80 @@ __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_ty

/* New range is completely covered? */
if (entry->addr < start && entry_end > end) {
- __e820__range_add(table, start, size, new_type);
- __e820__range_add(table, end, entry_end - end, entry->type);
+ __e820__range_add(table, start, size, new_type, entry->crypto_capable);
+ __e820__range_add(table, end, entry_end - end, entry->type, entry->crypto_capable);
+ entry->size = start - entry->addr;
+ real_updated_size += size;
+ continue;
+ }
+
+ /* Partially covered: */
+ final_start = max(start, entry->addr);
+ final_end = min(end, entry_end);
+ if (final_start >= final_end)
+ continue;
+
+ __e820__range_add(table, final_start, final_end - final_start,
+ new_type, entry->crypto_capable);
+
+ real_updated_size += final_end - final_start;
+
+ /*
+ * Left range could be head or tail, so need to update
+ * its size first:
+ */
+ entry->size -= final_end - final_start;
+ if (entry->addr < final_start)
+ continue;
+
+ entry->addr = final_end;
+ }
+ return real_updated_size;
+}
+
+/*
+ * Update crypto capabilities in a range
+ */
+static u64 __init __e820__range_update_crypto(struct e820_table *table,
+ u64 start, u64 size,
+ enum e820_crypto_capabilities crypto_capable)
+{
+ u64 end;
+ unsigned int i;
+ u64 real_updated_size = 0;
+
+ if (size > (ULLONG_MAX - start))
+ size = ULLONG_MAX - start;
+
+ end = start + size;
+ printk(KERN_DEBUG "e820: update crypto capabilities [mem %#018Lx-%#018Lx] ", start, end - 1);
+ pr_cont(" ==> ");
+ if (crypto_capable == E820_CRYPTO_CAPABLE)
+ pr_cont("crypto capable");
+ else
+ pr_cont("not crypto capable");
+ pr_cont("\n");
+
+ for (i = 0; i < table->nr_entries; i++) {
+ struct e820_entry *entry = &table->entries[i];
+ u64 final_start, final_end;
+ u64 entry_end;
+ enum e820_type type = entry->type;
+
+ entry_end = entry->addr + entry->size;
+
+ /* Completely covered by new range? */
+ if (entry->addr >= start && entry_end <= end) {
+ entry->crypto_capable = crypto_capable;
+ real_updated_size += entry->size;
+ continue;
+ }
+
+ /* New range is completely covered? */
+ if (entry->addr < start && entry_end > end) {
+ __e820__range_add(table, start, size, type, crypto_capable);
+ __e820__range_add(table, end, entry_end - end,
+ type, entry->crypto_capable);
entry->size = start - entry->addr;
real_updated_size += size;
continue;
@@ -510,7 +598,8 @@ __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_ty
if (final_start >= final_end)
continue;

- __e820__range_add(table, final_start, final_end - final_start, new_type);
+ __e820__range_add(table, final_start, final_end - final_start,
+ type, crypto_capable);

real_updated_size += final_end - final_start;

@@ -527,6 +616,11 @@ __e820__range_update(struct e820_table *table, u64 start, u64 size, enum e820_ty
return real_updated_size;
}

+u64 __init e820__range_mark_as_crypto_capable(u64 start, u64 size)
+{
+ return __e820__range_update_crypto(e820_table, start, size, E820_CRYPTO_CAPABLE);
+}
+
u64 __init e820__range_update(u64 start, u64 size, enum e820_type old_type, enum e820_type new_type)
{
return __e820__range_update(e820_table, start, size, old_type, new_type);
@@ -572,7 +666,9 @@ u64 __init e820__range_remove(u64 start, u64 size, enum e820_type old_type, bool

/* Is the new range completely covered? */
if (entry->addr < start && entry_end > end) {
- e820__range_add(end, entry_end - end, entry->type);
+ __e820__range_add(e820_table, end, entry_end - end,
+ entry->type, entry->crypto_capable);
+
entry->size = start - entry->addr;
real_removed_size += size;
continue;
@@ -1322,6 +1418,8 @@ 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