linux-kernel - [Part1 PATCH v4 03/17] x86/mm: Don't attempt to encrypt initrd under SEV

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Date:   Sat, 16 Sep 2017 07:34:04 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org, kvm@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
        Andy Lutomirski <luto@...nel.org>,
        Tom Lendacky <thomas.lendacky@....com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [Part1 PATCH v4 03/17] x86/mm: Don't attempt to encrypt initrd under SEV

From: Tom Lendacky <thomas.lendacky@....com>

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

Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: linux-kernel@...r.kernel.org
Cc: x86@...nel.org
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....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 82559867e0a9..967155e63afe 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -368,9 +368,11 @@ 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;
 
-- 
2.9.5