The following commit has been merged into the x86/sev branch of tip: Commit-ID: f75ff17fb48b1991d7a2822de5acc12bba240dc1 Gitweb: https://git.kernel.org/tip/f75ff17fb48b1991d7a2822de5acc12bba240dc1 Author: Nikunj A Dadhania <nikunj@xxxxxxx> AuthorDate: Wed, 09 Oct 2024 14:58:33 +05:30 Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx> CommitterDate: Wed, 16 Oct 2024 18:17:36 +02:00 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. Ensure that SNP guests will error out early, preventing delayed error reporting or undefined behavior. Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx> Link: https://lore.kernel.org/r/20241009092850.197575-3-nikunj@xxxxxxx --- arch/x86/mm/mem_encrypt_identity.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c index ac33b22..e6c7686 100644 --- a/arch/x86/mm/mem_encrypt_identity.c +++ b/arch/x86/mm/mem_encrypt_identity.c @@ -495,10 +495,10 @@ void __head sme_enable(struct boot_params *bp) unsigned int eax, ebx, ecx, edx; unsigned long feature_mask; unsigned long me_mask; - bool snp; + bool snp_en; u64 msr; - snp = snp_init(bp); + snp_en = snp_init(bp); /* Check for the SME/SEV support leaf */ eax = 0x80000000; @@ -531,8 +531,11 @@ void __head sme_enable(struct boot_params *bp) RIP_REL_REF(sev_status) = msr = __rdmsr(MSR_AMD64_SEV); feature_mask = (msr & MSR_AMD64_SEV_ENABLED) ? AMD_SEV_BIT : AMD_SME_BIT; - /* The SEV-SNP CC blob should never be present unless SEV-SNP is enabled. */ - if (snp && !(msr & MSR_AMD64_SEV_SNP_ENABLED)) + /* + * Any discrepancies between the presence of a CC blob and SNP + * enablement abort the guest. + */ + if (snp_en ^ !!(msr & MSR_AMD64_SEV_SNP_ENABLED)) snp_abort(); /* Check if memory encryption is enabled */
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