diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 3ed134f823fe..b006e6707eb0 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -269,6 +269,7 @@ #define X86_FEATURE_AMD_IBPB (13*32+12) /* "" Indirect Branch Prediction Barrier */ #define X86_FEATURE_AMD_IBRS (13*32+14) /* "" Indirect Branch Restricted Speculation */ #define X86_FEATURE_AMD_STIBP (13*32+15) /* "" Single Thread Indirect Branch Predictors */ +#define X86_FEATURE_AMD_SSBD (13*32+24) /* "" Speculative Store Bypass Disable */ #define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */ #define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */ diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 363ca2335a44..e2895f3f39f8 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -523,18 +523,20 @@ static enum ssb_mitigation __init __ssb_select_mitigation(void) if (mode == SPEC_STORE_BYPASS_DISABLE) { setup_force_cpu_cap(X86_FEATURE_SPEC_STORE_BYPASS_DISABLE); /* - * Intel uses the SPEC CTRL MSR Bit(2) for this, while AMD uses - * a completely different MSR and bit dependent on family. + * Intel uses the SPEC CTRL MSR Bit(2) for this, while AMD may + * use a completely different MSR and bit dependent on family. */ switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: + case X86_VENDOR_AMD: + if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL)) { + x86_amd_ssb_disable(); + break; + } x86_spec_ctrl_base |= SPEC_CTRL_SSBD; x86_spec_ctrl_mask |= SPEC_CTRL_SSBD; wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); break; - case X86_VENDOR_AMD: - x86_amd_ssb_disable(); - break; } } diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 4b3093b77edf..492f9c98bf6e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -709,6 +709,12 @@ static void init_speculation_control(struct cpuinfo_x86 *c) set_cpu_cap(c, X86_FEATURE_STIBP); set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); } + + if (cpu_has(c, X86_FEATURE_AMD_SSBD)) { + set_cpu_cap(c, X86_FEATURE_SSBD); + set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL); + clear_cpu_cap(c, X86_FEATURE_VIRT_SSBD); + } } void get_cpu_cap(struct cpuinfo_x86 *c) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 6eb103c7cb4a..2ea5e8266269 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -343,7 +343,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, /* cpuid 0x80000008.ebx */ const u32 kvm_cpuid_8000_0008_ebx_x86_features = - F(AMD_IBPB) | F(AMD_IBRS) | F(VIRT_SSBD) | F(AMD_SSB_NO); + F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) | + F(AMD_SSB_NO); /* cpuid 0xC0000001.edx */ const u32 kvm_supported_word5_x86_features = @@ -607,7 +608,12 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, entry->ebx |= F(VIRT_SSBD); entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features; cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX); - if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD)) + /* + * The preference is to use SPEC CTRL MSR instead of the + * VIRT_SPEC MSR. + */ + if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) && + !boot_cpu_has(X86_FEATURE_AMD_SSBD)) entry->ebx |= F(VIRT_SSBD); break; } diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index 72f159f4d456..8c28926dc900 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -175,7 +175,7 @@ static inline bool guest_cpuid_has_spec_ctrl(struct kvm_vcpu *vcpu) struct kvm_cpuid_entry2 *best; best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0); - if (best && (best->ebx & bit(X86_FEATURE_AMD_IBRS))) + if (best && (best->ebx & (bit(X86_FEATURE_AMD_IBRS | bit(X86_FEATURE_AMD_SSBD))))) return true; best = kvm_find_cpuid_entry(vcpu, 7, 0); return best && (best->edx & (bit(X86_FEATURE_SPEC_CTRL) | bit(X86_FEATURE_SPEC_CTRL_SSBD))); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index acbde1249b6f..9194698bbc28 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3197,7 +3197,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) return 1; /* The STIBP bit doesn't fault even if it's not advertised */ - if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP)) + if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP | SPEC_CTRL_SSBD)) return 1; svm->spec_ctrl = data;