linux-kernel - [PATCH 1/5] x86/boot/compressed/64: Introduce sev

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Date:   Mon, 19 Oct 2020 17:11:17 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     x86@...nel.org
Cc:     Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Kees Cook <keescook@...omium.org>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        Martin Radev <martin.b.radev@...il.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/5] x86/boot/compressed/64: Introduce sev_status

From: Joerg Roedel <jroedel@...e.de>

Introduce sev_status and initialize it together with sme_me_mask to have
an indicator which SEV features are enabled.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 arch/x86/boot/compressed/mem_encrypt.S | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
index dd07e7b41b11..0effd58f0095 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -71,6 +71,8 @@ SYM_FUNC_END(get_sev_encryption_bit)
 SYM_FUNC_START(set_sev_encryption_mask)
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 	push	%rbp
+	push	%rax
+	push	%rcx
 	push	%rdx
 
 	movq	%rsp, %rbp		/* Save current stack pointer */
@@ -81,10 +83,19 @@ SYM_FUNC_START(set_sev_encryption_mask)
 
 	bts	%rax, sme_me_mask(%rip)	/* Create the encryption mask */
 
+	/* Read sev_status */
+	movl	$MSR_AMD64_SEV, %ecx
+	rdmsr
+	shlq	$32, %rdx
+	orq	%rdx, %rax
+	movq	%rax, sev_status(%rip)
+
 .Lno_sev_mask:
 	movq	%rbp, %rsp		/* Restore original stack pointer */
 
 	pop	%rdx
+	pop	%rcx
+	pop	%rax
 	pop	%rbp
 #endif
 
@@ -96,5 +107,6 @@ SYM_FUNC_END(set_sev_encryption_mask)
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 	.balign	8
-SYM_DATA(sme_me_mask, .quad 0)
+SYM_DATA(sme_me_mask,		.quad 0)
+SYM_DATA(sev_status,		.quad 0)
 #endif
-- 
2.28.0