linux-kernel - [PATCH v12 08/46] x86/sev: Detect/setup SEV/SME features earlier in boot

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Message-ID: <20220307213356.2797205-9-brijesh.singh@amd.com>
Date:   Mon, 7 Mar 2022 15:33:18 -0600
From:   Brijesh Singh <brijesh.singh@....com>
To:     <x86@...nel.org>, <linux-kernel@...r.kernel.org>,
        <kvm@...r.kernel.org>, <linux-efi@...r.kernel.org>,
        <platform-driver-x86@...r.kernel.org>,
        <linux-coco@...ts.linux.dev>, <linux-mm@...ck.org>
CC:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        "H. Peter Anvin" <hpa@...or.com>, Ard Biesheuvel <ardb@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        "Vitaly Kuznetsov" <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        "Andy Lutomirski" <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Sergio Lopez <slp@...hat.com>, Peter Gonda <pgonda@...gle.com>,
        "Peter Zijlstra" <peterz@...radead.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        David Rientjes <rientjes@...gle.com>,
        Dov Murik <dovmurik@...ux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@....com>,
        Borislav Petkov <bp@...en8.de>,
        Michael Roth <michael.roth@....com>,
        Vlastimil Babka <vbabka@...e.cz>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        <brijesh.ksingh@...il.com>, <tony.luck@...el.com>,
        <marcorr@...gle.com>, <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Venu Busireddy <venu.busireddy@...cle.com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH v12 08/46] x86/sev: Detect/setup SEV/SME features earlier in boot

From: Michael Roth <michael.roth@....com>

sme_enable() handles feature detection for both SEV and SME. Future
patches will also use it for SEV-SNP feature detection/setup, which
will need to be done immediately after the first #VC handler is set up.
Move it now in preparation.

Reviewed-by: Venu Busireddy <venu.busireddy@...cle.com>
Signed-off-by: Michael Roth <michael.roth@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
 arch/x86/kernel/head64.c  |  3 ---
 arch/x86/kernel/head_64.S | 13 +++++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 4f5ecbbaae77..cbc285ddc4ac 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -192,9 +192,6 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	if (load_delta & ~PMD_PAGE_MASK)
 		for (;;);
 
-	/* Activate Secure Memory Encryption (SME) if supported and enabled */
-	sme_enable(bp);
-
 	/* Include the SME encryption mask in the fixup value */
 	load_delta += sme_get_me_mask();
 
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 9c63fc5988cd..9c2c3aff5ee4 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -69,6 +69,19 @@ SYM_CODE_START_NOALIGN(startup_64)
 	call	startup_64_setup_env
 	popq	%rsi
 
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	/*
+	 * Activate SEV/SME memory encryption if supported/enabled. This needs to
+	 * be done now, since this also includes setup of the SEV-SNP CPUID table,
+	 * which needs to be done before any CPUID instructions are executed in
+	 * subsequent code.
+	 */
+	movq	%rsi, %rdi
+	pushq	%rsi
+	call	sme_enable
+	popq	%rsi
+#endif
+
 	/* Now switch to __KERNEL_CS so IRET works reliably */
 	pushq	$__KERNEL_CS
 	leaq	.Lon_kernel_cs(%rip), %rax
-- 
2.25.1