Hardware support for faulting on the cpuid instruction is not required to emulate it, because cpuid triggers a VM exit anyways. KVM handles the relevant MSRs (MSR_PLATFORM_INFO and MSR_MISC_FEATURES_ENABLE) and upon a cpuid-induced VM exit checks the cpuid faulting state and the CPL. kvm_require_cpl is even kind enough to inject the GP fault for us. Signed-off-by: Kyle Huey <khuey@xxxxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/cpuid.c | 3 +++ arch/x86/kvm/cpuid.h | 10 ++++++++++ arch/x86/kvm/x86.c | 25 +++++++++++++++++++++++++ 4 files changed, 40 insertions(+) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index bdde807..954f37c 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -592,16 +592,18 @@ struct kvm_vcpu_arch { u64 pat; unsigned switch_db_regs; unsigned long db[KVM_NR_DB_REGS]; unsigned long dr6; unsigned long dr7; unsigned long eff_db[KVM_NR_DB_REGS]; unsigned long guest_debug_dr7; + u64 msr_platform_info; + u64 msr_misc_features_enables; u64 mcg_cap; u64 mcg_status; u64 mcg_ctl; u64 mcg_ext_ctl; u64 *mce_banks; /* Cache MMIO info */ diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index afa7bbb..0109bc0 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -862,16 +862,19 @@ void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx) trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx); } EXPORT_SYMBOL_GPL(kvm_cpuid); void kvm_emulate_cpuid(struct kvm_vcpu *vcpu) { u32 function, eax, ebx, ecx, edx; + if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0)) + return; + function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX); ecx = kvm_register_read(vcpu, VCPU_REGS_RCX); kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx); kvm_register_write(vcpu, VCPU_REGS_RAX, eax); kvm_register_write(vcpu, VCPU_REGS_RBX, ebx); kvm_register_write(vcpu, VCPU_REGS_RCX, ecx); kvm_register_write(vcpu, VCPU_REGS_RDX, edx); kvm_x86_ops->skip_emulated_instruction(vcpu); diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index 35058c2..994aa01 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -200,9 +200,19 @@ static inline int guest_cpuid_stepping(struct kvm_vcpu *vcpu) best = kvm_find_cpuid_entry(vcpu, 0x1, 0); if (!best) return -1; return x86_stepping(best->eax); } +static inline bool supports_cpuid_fault(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.msr_platform_info & PLATINFO_CPUID_FAULT; +} + +static inline bool cpuid_fault_enabled(struct kvm_vcpu *vcpu) +{ + return vcpu->arch.msr_misc_features_enables & CPUID_FAULT_ENABLE; +} + #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3017de0..797d0b0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -986,16 +986,18 @@ static u32 emulated_msrs[] = { MSR_IA32_TSC_ADJUST, MSR_IA32_TSCDEADLINE, MSR_IA32_MISC_ENABLE, MSR_IA32_MCG_STATUS, MSR_IA32_MCG_CTL, MSR_IA32_MCG_EXT_CTL, MSR_IA32_SMBASE, + MSR_PLATFORM_INFO, + MSR_MISC_FEATURES_ENABLES, }; static unsigned num_emulated_msrs; bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer) { if (efer & efer_reserved_bits) return false; @@ -2269,16 +2271,30 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; vcpu->arch.osvw.length = data; break; case MSR_AMD64_OSVW_STATUS: if (!guest_cpuid_has_osvw(vcpu)) return 1; vcpu->arch.osvw.status = data; break; + case MSR_PLATFORM_INFO: + if (!msr_info->host_initiated || + data & ~PLATINFO_CPUID_FAULT || + (!(data & PLATINFO_CPUID_FAULT) && + cpuid_fault_enabled(vcpu))) + return 1; + vcpu->arch.msr_platform_info = data; + break; + case MSR_MISC_FEATURES_ENABLES: + if (data & ~CPUID_FAULT_ENABLE || + (data & CPUID_FAULT_ENABLE && !supports_cpuid_fault(vcpu))) + return 1; + vcpu->arch.msr_misc_features_enables = data; + break; default: if (msr && (msr == vcpu->kvm->arch.xen_hvm_config.msr)) return xen_hvm_config(vcpu, data); if (kvm_pmu_is_valid_msr(vcpu, msr)) return kvm_pmu_set_msr(vcpu, msr_info); if (!ignore_msrs) { vcpu_unimpl(vcpu, "unhandled wrmsr: 0x%x data 0x%llx\n", msr, data); @@ -2483,16 +2499,22 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; msr_info->data = vcpu->arch.osvw.length; break; case MSR_AMD64_OSVW_STATUS: if (!guest_cpuid_has_osvw(vcpu)) return 1; msr_info->data = vcpu->arch.osvw.status; break; + case MSR_PLATFORM_INFO: + msr_info->data = vcpu->arch.msr_platform_info; + break; + case MSR_MISC_FEATURES_ENABLES: + msr_info->data = vcpu->arch.msr_misc_features_enables; + break; default: if (kvm_pmu_is_valid_msr(vcpu, msr_info->index)) return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data); if (!ignore_msrs) { vcpu_unimpl(vcpu, "unhandled rdmsr: 0x%x\n", msr_info->index); return 1; } else { vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n", msr_info->index); @@ -7508,16 +7530,19 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) kvm_clear_async_pf_completion_queue(vcpu); kvm_async_pf_hash_reset(vcpu); vcpu->arch.apf.halted = false; if (!init_event) { kvm_pmu_reset(vcpu); vcpu->arch.smbase = 0x30000; + + vcpu->arch.msr_platform_info = PLATINFO_CPUID_FAULT; + vcpu->arch.msr_misc_features_enables = 0; } memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs)); vcpu->arch.regs_avail = ~0; vcpu->arch.regs_dirty = ~0; kvm_x86_ops->vcpu_reset(vcpu, init_event); } -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html