[Xen-devel] [PATCH v9 15/38] x86/boot/e820: Add support to determine the E820 type of an address

[Tom Lendacky <thomas.lendacky@xxxxxxx>]

Add a function that will return the E820 type associated with an address
range.

Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
 arch/x86/include/asm/e820/api.h |    2 ++
 arch/x86/kernel/e820.c          |   26 +++++++++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index a504adc..cd266d8 100644
--- a/arch/x86/include/asm/e820/api.h
+++ b/arch/x86/include/asm/e820/api.h
@@ -39,6 +39,8 @@
 extern void e820__reallocate_tables(void);
 extern void e820__register_nosave_regions(unsigned long limit_pfn);
 
+extern int  e820__get_entry_type(u64 start, u64 end);
+
 /*
  * Returns true iff the specified range [start,end) is completely contained 
inside
  * the ISA region.
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 532da61..71c11ad 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -96,7 +96,8 @@ bool e820__mapped_any(u64 start, u64 end, enum e820_type type)
  * Note: this function only works correctly once the E820 table is sorted and
  * not-overlapping (at least for the range specified), which is the case 
normally.
  */
-bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
+static struct e820_entry *__e820__mapped_all(u64 start, u64 end,
+                                            enum e820_type type)
 {
        int i;
 
@@ -122,9 +123,28 @@ bool __init e820__mapped_all(u64 start, u64 end, enum 
e820_type type)
                 * coverage of the desired range exists:
                 */
                if (start >= end)
-                       return 1;
+                       return entry;
        }
-       return 0;
+
+       return NULL;
+}
+
+/*
+ * This function checks if the entire range <start,end> is mapped with type.
+ */
+bool __init e820__mapped_all(u64 start, u64 end, enum e820_type type)
+{
+       return __e820__mapped_all(start, end, type);
+}
+
+/*
+ * This function returns the type associated with the range <start,end>.
+ */
+int e820__get_entry_type(u64 start, u64 end)
+{
+       struct e820_entry *entry = __e820__mapped_all(start, end, 0);
+
+       return entry ? entry->type : -EINVAL;
 }
 
 /*


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