linux-kernel - [tip:x86/mm] x86/boot/e820: Add support to determine the E820 type of an address

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Date:   Tue, 18 Jul 2017 03:52:41 -0700
From:   tip-bot for Tom Lendacky <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, dyoung@...hat.com,
        linux-kernel@...r.kernel.org, mst@...hat.com, rkrcmar@...hat.com,
        luto@...nel.org, toshi.kani@....com, arnd@...db.de,
        pbonzini@...hat.com, glider@...gle.com, peterz@...radead.org,
        thomas.lendacky@....com, bp@...e.de, konrad.wilk@...cle.com,
        aryabinin@...tuozzo.com, brijesh.singh@....com, mingo@...nel.org,
        hpa@...or.com, bp@...en8.de, torvalds@...ux-foundation.org,
        dvyukov@...gle.com, riel@...hat.com, matt@...eblueprint.co.uk,
        corbet@....net, lwoodman@...hat.com
Subject: [tip:x86/mm] x86/boot/e820: Add support to determine the E820 type
 of an address

Commit-ID:  d68baa3fa6e4d703fd0c7954ee5c739789e7242f
Gitweb:     http://git.kernel.org/tip/d68baa3fa6e4d703fd0c7954ee5c739789e7242f
Author:     Tom Lendacky <thomas.lendacky@....com>
AuthorDate: Mon, 17 Jul 2017 16:10:12 -0500
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 18 Jul 2017 11:38:01 +0200

x86/boot/e820: Add support to determine the E820 type of an address

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

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Cc: Alexander Potapenko <glider@...gle.com>
Cc: Andrey Ryabinin <aryabinin@...tuozzo.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brijesh Singh <brijesh.singh@....com>
Cc: Dave Young <dyoung@...hat.com>
Cc: Dmitry Vyukov <dvyukov@...gle.com>
Cc: Jonathan Corbet <corbet@....net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Larry Woodman <lwoodman@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@...hat.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Cc: Rik van Riel <riel@...hat.com>
Cc: Toshimitsu Kani <toshi.kani@....com>
Cc: kasan-dev@...glegroups.com
Cc: kvm@...r.kernel.org
Cc: linux-arch@...r.kernel.org
Cc: linux-doc@...r.kernel.org
Cc: linux-efi@...r.kernel.org
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/b797aaa588803bf33263d5dd8c32377668fa931a.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 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__setup_pci_gap(void);
 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 @@ EXPORT_SYMBOL_GPL(e820__mapped_any);
  * 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;
 }
 
 /*