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

[tip-bot for Tom Lendacky]

Commit-ID:  682af54399b6111730aec0be63e5f6a3a3359a76
Gitweb:     https://git.kernel.org/tip/682af54399b6111730aec0be63e5f6a3a3359a76
Author:     Tom Lendacky <thomas.lendacky@xxxxxxx>
AuthorDate: Fri, 20 Oct 2017 09:30:45 -0500
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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@xxxxxxx>
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Tested-by: Borislav Petkov <bp@xxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20171020143059.3291-4-brijesh.singh@xxxxxxx

---
 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;