linux-kernel - [RFC Part1 PATCH v3 04/17] x86/mm: Don't attempt to encrypt initrd under SEV

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Message-Id: <20170724190757.11278-5-brijesh.singh@amd.com>
Date:   Mon, 24 Jul 2017 14:07:44 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-efi@...r.kernel.org, linuxppc-dev@...ts.ozlabs.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>,
        Tony Luck <tony.luck@...el.com>,
        Piotr Luc <piotr.luc@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Reza Arbab <arbab@...ux.vnet.ibm.com>,
        David Howells <dhowells@...hat.com>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Laura Abbott <labbott@...hat.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Eric Biederman <ebiederm@...ssion.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Jonathan Corbet <corbet@....net>,
        Dave Airlie <airlied@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Arnd Bergmann <arnd@...db.de>, Tejun Heo <tj@...nel.org>,
        Christoph Lameter <cl@...ux.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [RFC Part1 PATCH v3 04/17] 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 encyrpted so do not try to encrypt it.

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 0bfe0c1..01d56a1 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -379,9 +379,11 @@ 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 encyrpted, 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;
 
-- 
2.9.4