Advertise the Zhaoxin SM2 instruction support to guests via CPUID 0xC0000001 EDX bits 0 (SM2) and 1 (SM2_EN). The SM2 instruction (encoding F2 0F A6 C0) implements the SM2 elliptic-curve public-key cryptography algorithm specified in GM/T 0003-2012; the hardware-level behavior is documented in the Zhaoxin GMI Instruction Set Reference, chapter 1 ("SM2"). The instruction multiplexes its sub-functions on the RDX[5:0] control word: encryption (subsection 1.1), decryption (1.2), signing (1.3), signature verification (1.4), the three key-exchange sub-operations of section 1.5 (1.5.1 SM2 key-pair generation, which the spec also uses for the initiator's ephemeral key; 1.5.2 responder shared-key derivation; 1.5.3 initiator shared-key derivation), and two preprocess steps for identity and message hashing (1.6.1 and 1.6.2). The instruction is user-mode and available in all CPU modes, with no associated MSR control. The SM2 and SM2_EN bits are redundant by hardware design (set or cleared together) and both serve purely as CPUID-level feature-presence reporting flags requiring no KVM emulation. Both bits are advertised because different software may probe either one when checking for SM2 availability. Signed-off-by: Ewan Hai --- arch/x86/kvm/cpuid.c | 2 ++ arch/x86/kvm/reverse_cpuid.h | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index e69156b54cff..1eb4b88aaa80 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1272,6 +1272,8 @@ void kvm_initialize_cpu_caps(void) kvm_cpu_cap_set(X86_FEATURE_NULL_SEL_CLR_BASE); kvm_cpu_cap_init(CPUID_C000_0001_EDX, + F(SM2), + F(SM2_EN), F(XSTORE), F(XSTORE_EN), F(XCRYPT), diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h index 657f5f743ed9..7b55110cc046 100644 --- a/arch/x86/kvm/reverse_cpuid.h +++ b/arch/x86/kvm/reverse_cpuid.h @@ -76,6 +76,10 @@ #define KVM_X86_FEATURE_TSA_SQ_NO KVM_X86_FEATURE(CPUID_8000_0021_ECX, 1) #define KVM_X86_FEATURE_TSA_L1_NO KVM_X86_FEATURE(CPUID_8000_0021_ECX, 2) +/* Zhaoxin/Centaur sub-features, CPUID level 0xC0000001 (EDX) */ +#define X86_FEATURE_SM2 KVM_X86_FEATURE(CPUID_C000_0001_EDX, 0) +#define X86_FEATURE_SM2_EN KVM_X86_FEATURE(CPUID_C000_0001_EDX, 1) + struct cpuid_reg { u32 function; u32 index; -- 2.34.1