linux-kernel - [tip:x86/asm] x86/mm: Don't attempt to encrypt initrd under SEV

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Message-ID: <tip-682af54399b6111730aec0be63e5f6a3a3359a76@git.kernel.org>
Date:   Tue, 7 Nov 2017 06:43:40 -0800
From:   tip-bot for Tom Lendacky <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, linux-kernel@...r.kernel.org,
        brijesh.singh@....com, thomas.lendacky@....com, bp@...e.de,
        hpa@...or.com, bp@...en8.de, tglx@...utronix.de, luto@...nel.org
Subject: [tip:x86/asm] x86/mm: Don't attempt to encrypt initrd under SEV

Commit-ID:  682af54399b6111730aec0be63e5f6a3a3359a76
Gitweb:     https://git.kernel.org/tip/682af54399b6111730aec0be63e5f6a3a3359a76
Author:     Tom Lendacky <thomas.lendacky@....com>
AuthorDate: Fri, 20 Oct 2017 09:30:45 -0500
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue, 7 Nov 2017 15:35:55 +0100

x86/mm: Don't attempt to encrypt initrd under SEV

When SEV is active the initrd/initramfs will already have already been
placed in memory encrypted so do not try to encrypt it.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Tested-by: Borislav Petkov <bp@...e.de>
Cc: kvm@...r.kernel.org
Cc: Borislav Petkov <bp@...en8.de>
Cc: Andy Lutomirski <luto@...nel.org>
Link: https://lkml.kernel.org/r/20171020143059.3291-4-brijesh.singh@amd.com

---
 arch/x86/kernel/setup.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 0957dd7..507100a 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -380,9 +380,11 @@ static void __init reserve_initrd(void)
 	 * If SME is active, this memory will be marked encrypted by the
 	 * kernel when it is accessed (including relocation). However, the
 	 * ramdisk image was loaded decrypted by the bootloader, so make
-	 * sure that it is encrypted before accessing it.
+	 * sure that it is encrypted before accessing it. For SEV the
+	 * ramdisk will already be encrypted, so only do this for SME.
 	 */
-	sme_early_encrypt(ramdisk_image, ramdisk_end - ramdisk_image);
+	if (sme_active())
+		sme_early_encrypt(ramdisk_image, ramdisk_end - ramdisk_image);
 
 	initrd_start = 0;