diff mbox series

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

Message ID 20220113213027.457282-4-martin.fernandez@eclypsium.com
State New
Headers show
Series x86: Show in sysfs if a memory node is able to do encryption | expand

Commit Message

Martin Fernandez Jan. 13, 2022, 9:30 p.m. UTC 
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@eclypsium.com>
---
 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(-)

Comments

Dave Hansen Jan. 14, 2022, 6:17 p.m. UTC | #1 
On 1/13/22 1:30 PM, Martin Fernandez wrote:
> +/*
> + * 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)

This looks like an almost pure copy-and-paste of a 70-line function.
That's not the end of the world, but it does seem like a place where
refactoring is in order.

The rest of this series looks pretty straightforward, but this part in
particular is the most worrying.
Martin Fernandez Jan. 17, 2022, 12:42 p.m. UTC | #2 
On 1/14/22, Dave Hansen <dave.hansen@intel.com> wrote:
> On 1/13/22 1:30 PM, Martin Fernandez wrote:
>> +/*
>> + * 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)
>
> This looks like an almost pure copy-and-paste of a 70-line function.
> That's not the end of the world, but it does seem like a place where
> refactoring is in order.
>
> The rest of this series looks pretty straightforward, but this part in
> particular is the most worrying.
>

Yep, I'm not super happy with this either. I'll check it out to see
what we can do. Btw e820__range_remove is quite similiar too.
Martin Fernandez Jan. 26, 2022, 2:03 p.m. UTC | #3 
> On 1/14/22, Dave Hansen <dave.hansen@intel.com> wrote:
>> On 1/13/22 1:30 PM, Martin Fernandez wrote:
>>> +/*
>>> + * 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)
>>
>> This looks like an almost pure copy-and-paste of a 70-line function.
>> That's not the end of the world, but it does seem like a place where
>> refactoring is in order.

Introducing a for_each to iterate over the table is one of the
improvements I'm thinking of. Do you think it's a good idea to
introduce it in this patch (changing all the relevant for loops for
this new for_each) or should I do it in a separate patch?
diff mbox series

Patch

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: */