From: Brijesh Singh <brijesh.singh@xxxxxxx> Add CPU feature detection for Secure Encrypted Virtualization with Secure Nested Paging. This feature adds a strong memory integrity protection to help prevent malicious hypervisor-based attacks like data replay, memory re-mapping, and more. Link: https://lore.kernel.org/all/YrGINaPc3cojG6%2F3@xxxxxxx/ Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxxx> Signed-off-by: Ashish Kalra <Ashish.Kalra@xxxxxxx> Signed-off-by: Michael Roth <michael.roth@xxxxxxx> --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kernel/cpu/amd.c | 5 +++-- tools/arch/x86/include/asm/cpufeatures.h | 1 + 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 1419c4e04d45..480b4eaef310 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -420,6 +420,7 @@ #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ +#define X86_FEATURE_SEV_SNP (19*32+ 4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */ #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 860b60273df3..c7884198ad5b 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -558,8 +558,8 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) * SME feature (set in scattered.c). * If the kernel has not enabled SME via any means then * don't advertise the SME feature. - * For SEV: If BIOS has not enabled SEV then don't advertise the - * SEV and SEV_ES feature (set in scattered.c). + * For SEV: If BIOS has not enabled SEV then don't advertise SEV and + * any additional functionality based on it. * * In all cases, since support for SME and SEV requires long mode, * don't advertise the feature under CONFIG_X86_32. @@ -594,6 +594,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) clear_sev: setup_clear_cpu_cap(X86_FEATURE_SEV); setup_clear_cpu_cap(X86_FEATURE_SEV_ES); + setup_clear_cpu_cap(X86_FEATURE_SEV_SNP); } } diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h index b71f4f2ecdd5..e81606fcd2ab 100644 --- a/tools/arch/x86/include/asm/cpufeatures.h +++ b/tools/arch/x86/include/asm/cpufeatures.h @@ -417,6 +417,7 @@ #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ +#define X86_FEATURE_SEV_SNP (19*32+ 4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */ #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ -- 2.25.1
