linux-kernel - [PATCH v11 06/20] x86/sev: Handle failures from snp

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Message-ID: <20240731150811.156771-7-nikunj@amd.com>
Date: Wed, 31 Jul 2024 20:37:57 +0530
From: Nikunj A Dadhania <nikunj@....com>
To: <linux-kernel@...r.kernel.org>, <thomas.lendacky@....com>, <bp@...en8.de>,
	<x86@...nel.org>, <kvm@...r.kernel.org>
CC: <mingo@...hat.com>, <tglx@...utronix.de>, <dave.hansen@...ux.intel.com>,
	<pgonda@...gle.com>, <seanjc@...gle.com>, <pbonzini@...hat.com>,
	<nikunj@....com>
Subject: [PATCH v11 06/20] x86/sev: Handle failures from snp_init()

Address the ignored failures from snp_init() in sme_enable(). Add error
handling for scenarios where snp_init() fails to retrieve the SEV-SNP CC
blob or encounters issues while parsing the CC blob. This change ensures
that SNP guests will error out early, preventing delayed error reporting or
undefined behavior.

Signed-off-by: Nikunj A Dadhania <nikunj@....com>
---
 arch/x86/mm/mem_encrypt_identity.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index ac33b2263a43..e83b363c5e68 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -535,6 +535,13 @@ void __head sme_enable(struct boot_params *bp)
 	if (snp && !(msr & MSR_AMD64_SEV_SNP_ENABLED))
 		snp_abort();
 
+	/*
+	 * The SEV-SNP CC blob should be present and parsing CC blob should
+	 * succeed when SEV-SNP is enabled.
+	 */
+	if (!snp && (msr & MSR_AMD64_SEV_SNP_ENABLED))
+		snp_abort();
+
 	/* Check if memory encryption is enabled */
 	if (feature_mask == AMD_SME_BIT) {
 		if (!(bp->hdr.xloadflags & XLF_MEM_ENCRYPTION))
-- 
2.34.1