x86/mm: Add Secure Memory Encryption (SME) support

Add support for Secure Memory Encryption (SME). This initial support
provides a Kconfig entry to build the SME support into the kernel and
defines the memory encryption mask that will be used in subsequent
patches to mark pages as encrypted.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/a6c34d16caaed3bc3e2d6f0987554275bd291554.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 781521b7cf9ef6b6766dac9249a3568f257c4fa8..ba7b93d08d00b441ecd1cba49cedaf6ba698c2e0 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1415,6 +1415,31 @@ config X86_DIRECT_GBPAGES
          supports them), so don't confuse the user by printing
          that we have them enabled.
 
+config ARCH_HAS_MEM_ENCRYPT
+       def_bool y
+
+config AMD_MEM_ENCRYPT
+       bool "AMD Secure Memory Encryption (SME) support"
+       depends on X86_64 && CPU_SUP_AMD
+       ---help---
+         Say yes to enable support for the encryption of system memory.
+         This requires an AMD processor that supports Secure Memory
+         Encryption (SME).
+
+config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
+       bool "Activate AMD Secure Memory Encryption (SME) by default"
+       default y
+       depends on AMD_MEM_ENCRYPT
+       ---help---
+         Say yes to have system memory encrypted by default if running on
+         an AMD processor that supports Secure Memory Encryption (SME).
+
+         If set to Y, then the encryption of system memory can be
+         deactivated with the mem_encrypt=off command line option.
+
+         If set to N, then the encryption of system memory can be
+         activated with the mem_encrypt=on command line option.
+
 # Common NUMA Features
 config NUMA
        bool "Numa Memory Allocation and Scheduler Support"

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
new file mode 100644 (file)
index 0000000..a105796
--- /dev/null
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -0,0 +1,30 @@
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __X86_MEM_ENCRYPT_H__
+#define __X86_MEM_ENCRYPT_H__
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+
+extern unsigned long sme_me_mask;
+
+#else  /* !CONFIG_AMD_MEM_ENCRYPT */
+
+#define sme_me_mask    0UL
+
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __X86_MEM_ENCRYPT_H__ */

diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 0fbdcb64f9f836c0556ca0abcca4c673aea143f0..a94a7b663d5fe6e061481c0586ad1c0f330f9978 100644 (file)
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -39,3 +39,4 @@ obj-$(CONFIG_X86_INTEL_MPX)   += mpx.o
 obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) += pkeys.o
 obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o
 
+obj-$(CONFIG_AMD_MEM_ENCRYPT)  += mem_encrypt.o

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
new file mode 100644 (file)
index 0000000..b99d469
--- /dev/null
+++ b/arch/x86/mm/mem_encrypt.c
@@ -0,0 +1,21 @@
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+
+/*
+ * Since SME related variables are set early in the boot process they must
+ * reside in the .data section so as not to be zeroed out when the .bss
+ * section is later cleared.
+ */
+unsigned long sme_me_mask __section(.data) = 0;
+EXPORT_SYMBOL_GPL(sme_me_mask);

diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
new file mode 100644 (file)
index 0000000..59769f7
--- /dev/null
+++ b/include/linux/mem_encrypt.h
@@ -0,0 +1,35 @@
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __MEM_ENCRYPT_H__
+#define __MEM_ENCRYPT_H__
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_ARCH_HAS_MEM_ENCRYPT
+
+#include <asm/mem_encrypt.h>
+
+#else  /* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
+
+#define sme_me_mask    0UL
+
+#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */
+
+static inline bool sme_active(void)
+{
+       return !!sme_me_mask;
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __MEM_ENCRYPT_H__ */